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<h1 class="TITLE"><a id="AEN2" name="AEN2">Slackware Linux Essentials</a></h1>
<p><img src="slackware_logo.png" align="CENTER" /></p>
<h3 class="AUTHOR"><a id="AEN30" name="AEN30"></a>Alan Hicks</h3>
<h3 class="AUTHOR"><a id="AEN43" name="AEN43"></a>Chris Lumens</h3>
<h3 class="AUTHOR"><a id="AEN47" name="AEN47"></a>David Cantrell</h3>
<h3 class="AUTHOR"><a id="AEN50" name="AEN50"></a>Logan Johnson</h3>
<p class="COPYRIGHT">Copyright © 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005
Slackware Linux, Inc.</p>
<div class="LEGALNOTICE"><a id="TRADEMARKS" name="TRADEMARKS"></a>
<p>Slackware Linux is a registered trademark of Patrick Volkerding and Slackware Linux,
Inc.</p>
<p>Linux is a registered trademark of Linus Torvalds.</p>
<p>America Online and AOL are registered trademarks of America Online, Inc. in the United
States and/or other countries.</p>
<p>Apple, FireWire, Mac, Macintosh, Mac OS, Quicktime, and TrueType are trademarks of
Apple Computer, Inc., registered in the United States and other countries.</p>
<p>IBM, AIX, EtherJet, Netfinity, OS/2, PowerPC, PS/2, S/390, and ThinkPad are trademarks
of International Business Machines Corporation in the United States, other countries, or
both.</p>
<p>IEEE, POSIX, and 802 are registered trademarks of Institute of Electrical and
Electronics Engineers, Inc. in the United States.</p>
<p>Intel, Celeron, EtherExpress, i386, i486, Itanium, Pentium, and Xeon are trademarks or
registered trademarks of Intel Corporation or its subsidiaries in the United States and
other countries.</p>
<p>Microsoft, IntelliMouse, MS-DOS, Outlook, Windows, Windows Media and Windows NT are
either registered trademarks or trademarks of Microsoft Corporation in the United States
and/or other countries.</p>
<p>Netscape and the Netscape Navigator are registered trademarks of Netscape
Communications Corporation in the U.S. and other countries.</p>
<p>Red Hat, RPM, are trademarks or registered trademarks of Red Hat, Inc. in the United
States and other countries.</p>
<p>XFree86 is a trademark of The XFree86 Project, Inc.</p>
<p>Many of the designations used by manufacturers and sellers to distinguish their
products are claimed as trademarks. Where those designations appear in this document, and
Slackware Linux, Inc. was aware of the trademark claim, the designations have been
followed by the “™” or the “®” symbol.</p>
</div>
<span class="ISBN">1-57176-338-4<br />
</span>
<div class="DOCFORAMTNAVI">[ <a href="./index.html">Split HTML</a> / <a
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</div>
<div class="TOC">
<dl>
<dt><b>Table of Contents</b></dt>
<dt><a href="#BOOK-PREFACE">Preface</a></dt>
<dt>1 <a href="#INTRODUCTION">An Introduction to Slackware Linux</a></dt>
<dd>
<dl>
<dt>1.1 <a href="#INTRODUCTION-LINUX">What is Linux?</a></dt>
<dd>
<dl>
<dt>1.1.1 <a href="#INTRODUCTION-LINUX-GNU">A Word on GNU</a></dt>
</dl>
</dd>
<dt>1.2 <a href="#INTRODUCTION-SLACKWARE">What is Slackware?</a></dt>
<dt>1.3 <a href="#INTRODUCTION-OPENSOURCE">Open Source and Free Software</a></dt>
</dl>
</dd>
<dt>2 <a href="#HELP">Help</a></dt>
<dd>
<dl>
<dt>2.1 <a href="#HELP-SYSTEM">System Help</a></dt>
<dd>
<dl>
<dt>2.1.1 <a href="#HELP-SYSTEM-MAN"><tt class="COMMAND">man</tt></a></dt>
<dt>2.1.2 <a href="#HELP-SYSTEM-DOC">The <tt class="FILENAME">/usr/doc</tt>
Directory</a></dt>
<dt>2.1.3 <a href="#HELP-SYSTEM-HOWTO">HOWTOs and mini-HOWTOs</a></dt>
</dl>
</dd>
<dt>2.2 <a href="#HELP-ONLINE">Online Help</a></dt>
<dd>
<dl>
<dt>2.2.1 <a href="#HELP-ONLINE-OFFICIAL">The Official Website and Help Forums</a></dt>
<dt>2.2.2 <a href="#HELP-ONLINE-EMAIL">E-mail Support</a></dt>
<dt>2.2.3 <a href="#HELP-ONLINE-NONOFFICIAL">Non-Official Websites and Help
Forums</a></dt>
</dl>
</dd>
</dl>
</dd>
<dt>3 <a href="#INSTALLATION">Installation</a></dt>
<dd>
<dl>
<dt>3.1 <a href="#INSTALLATION-GETTING">Getting Slackware</a></dt>
<dd>
<dl>
<dt>3.1.1 <a href="#AEN641">The Official Disc and Box Sets</a></dt>
<dt>3.1.2 <a href="#AEN683">Via the Internet</a></dt>
</dl>
</dd>
<dt>3.2 <a href="#INSTALLATION-REQUIREMENTS">System Requirements</a></dt>
<dd>
<dl>
<dt>3.2.1 <a href="#INSTALLATION-SOFTWARE-SERIES">The Software Series</a></dt>
<dt>3.2.2 <a href="#INSTALLATION-METHODS">Installation Methods</a></dt>
<dt>3.2.3 <a href="#INSTALLATION-INSTALLATION-METHODS-BOOTDISK">Boot Disk</a></dt>
<dt>3.2.4 <a href="#INSTALLATION-INSTALLATION-METHODS-ROOTDISK">Root Disk</a></dt>
<dt>3.2.5 <a href="#INSTALLATION-SUPPLEMENTAL-DISK">Supplemental Disk</a></dt>
<dt>3.2.6 <a href="#INSTALLATION-MAKING-THE-DISKS">Making the Disks</a></dt>
</dl>
</dd>
<dt>3.3 <a href="#INSTALLATION-PARTITIONING">Partitioning</a></dt>
<dt>3.4 <a href="#INSTALLATION-SETUP">The <tt class="COMMAND">setup</tt> Program</a></dt>
<dd>
<dl>
<dt>3.4.1 <a href="#AEN993">HELP</a></dt>
<dt>3.4.2 <a href="#AEN1001">KEYMAP</a></dt>
<dt>3.4.3 <a href="#AEN1013">ADDSWAP</a></dt>
<dt>3.4.4 <a href="#AEN1023">TARGET</a></dt>
<dt>3.4.5 <a href="#AEN1035">SOURCE</a></dt>
<dt>3.4.6 <a href="#AEN1054">SELECT</a></dt>
<dt>3.4.7 <a href="#AEN1062">INSTALL</a></dt>
<dt>3.4.8 <a href="#AEN1100">CONFIGURE</a></dt>
</dl>
</dd>
</dl>
</dd>
<dt>4 <a href="#SYSTEM-CONFIGURATION">System Configuration</a></dt>
<dd>
<dl>
<dt>4.1 <a href="#SYSTEM-CONFIGURATION-OVERVIEW">System Overview</a></dt>
<dd>
<dl>
<dt>4.1.1 <a href="#SYSTEM-CONFIGURATION-LAYOUT">File System Layout</a></dt>
<dt>4.1.2 <a href="#SYSTEM-CONFIGURATION-FINDING">Finding Files</a></dt>
<dt>4.1.3 <a href="#SYSTEM-CONFIGURATION-RCD">The <tt class="FILENAME">/etc/rc.d</tt>
Directory</a></dt>
</dl>
</dd>
<dt>4.2 <a href="#SYSTEM-CONFIGURATION-KERNEL">Selecting a Kernel</a></dt>
<dd>
<dl>
<dt>4.2.1 <a href="#AEN1581">The <tt class="FILENAME">/kernels</tt> Directory on the
Slackware CD-ROM</a></dt>
<dt>4.2.2 <a href="#SYSTEM-CONFIGURATION-KERNEL-COMPILE">Compiling a Kernel from
Source</a></dt>
<dt>4.2.3 <a href="#SYSTEM-CONFIGURATION-KERNEL-MODULES">Using Kernel Modules</a></dt>
</dl>
</dd>
</dl>
</dd>
<dt>5 <a href="#NETWORK-CONFIGURATION">Network Configuration</a></dt>
<dd>
<dl>
<dt>5.1 <a href="#NETWORK-CONFIGURATION-NETCONFIG">Introduction: netconfig is your
friend.</a></dt>
<dt>5.2 <a href="#NETWORK-CONFIGURATION-HARDWARE">Network Hardware Configuration</a></dt>
<dd>
<dl>
<dt>5.2.1 <a href="#NETWORK-CONFIGURATION-HARDWARE-MODULES">Loading Network
Modules</a></dt>
<dt>5.2.2 <a href="#NETWORK-CONFIGURATION-HARDWARE-LAN">LAN (10/100/1000Base-T and
Base-2) cards</a></dt>
<dt>5.2.3 <a href="#NETWORK-CONFIGURATION-HARDWARE-MODEMS">Modems</a></dt>
<dt>5.2.4 <a href="#NETWORK-CONFIGURATION-HARDWARE-PCMCIA">PCMCIA</a></dt>
</dl>
</dd>
<dt>5.3 <a href="#NETWORK-CONFIGURATION-TCPIP">TCP/IP Configuration</a></dt>
<dd>
<dl>
<dt>5.3.1 <a href="#NETWORK-CONFIGURATION-TCPIP-DHCP">DHCP</a></dt>
<dt>5.3.2 <a href="#NETWORK-CONFIGURATION-TCPIP-STATIC">Static IP</a></dt>
<dt>5.3.3 <a href="#NETWORK-CONFIGURATION-TCPIP-CONF"><tt
class="FILENAME">/etc/rc.d/rc.inet1.conf</tt></a></dt>
<dt>5.3.4 <a href="#NETWORK-CONFIGURATION-TCPIP-RESOLVER"><tt
class="FILENAME">/etc/resolv.conf</tt></a></dt>
<dt>5.3.5 <a href="#NETWORK-CONFIGURATION-TCPIP-HOSTS"><tt
class="FILENAME">/etc/hosts</tt></a></dt>
</dl>
</dd>
<dt>5.4 <a href="#NETWORK-CONFIGURATION-PPP">PPP</a></dt>
<dd>
<dl>
<dt>5.4.1 <a href="#AEN1954"><tt class="COMMAND">pppsetup</tt></a></dt>
<dt>5.4.2 <a href="#AEN1969"><tt class="FILENAME">/etc/ppp</tt></a></dt>
</dl>
</dd>
<dt>5.5 <a href="#NETWORK-CONFIGURATION-WIRELESS">Wireless</a></dt>
<dd>
<dl>
<dt>5.5.1 <a href="#AEN2033">Hardware Support</a></dt>
<dt>5.5.2 <a href="#AEN2044">Configure the Wireless Settings</a></dt>
<dt>5.5.3 <a href="#AEN2101">Configure the Network</a></dt>
</dl>
</dd>
<dt>5.6 <a href="#NETWORK-CONFIGURATION-NFS">Network File Systems</a></dt>
<dd>
<dl>
<dt>5.6.1 <a href="#NETWORK-CONFIGURATION-NSF-SMB">SMB/Samba/CIFS</a></dt>
<dt>5.6.2 <a href="#NETWORK-CONFIGURATION-NFS-NFS">Network File System (NFS)</a></dt>
</dl>
</dd>
</dl>
</dd>
<dt>6 <a href="#X-WINDOW-SYSTEM">X Configuration</a></dt>
<dd>
<dl>
<dt>6.1 <a href="#X-WINDOW-SYSTEM-XORGCONFIG"><tt
class="COMMAND">xorgconfig</tt></a></dt>
<dt>6.2 <a href="#X-WINDOW-SYSTEM-XORGSETUP"><tt class="COMMAND">xorgsetup</tt></a></dt>
<dt>6.3 <a href="#X-WINDOW-SYSTEM-XINITRC">xinitrc</a></dt>
<dt>6.4 <a href="#X-WINDOW-SYSTEM-XWMCONFIG"><tt class="COMMAND">xwmconfig</tt></a></dt>
<dt>6.5 <a href="#X-WINDOW-SYSTEM-XDM"><tt class="COMMAND">xdm</tt></a></dt>
</dl>
</dd>
<dt>7 <a href="#BOOTING">Booting</a></dt>
<dd>
<dl>
<dt>7.1 <a href="#BOOTING-LILO">LILO</a></dt>
<dt>7.2 <a href="#BOOTING-LOADLIN">LOADLIN</a></dt>
<dt>7.3 <a href="#BOOTING-DUAL">Dual Booting</a></dt>
<dd>
<dl>
<dt>7.3.1 <a href="#BOOTING-DUAL-WINDOWS">Windows</a></dt>
<dt>7.3.2 <a href="#BOOTING-DUAL-LINUX">Linux</a></dt>
</dl>
</dd>
</dl>
</dd>
<dt>8 <a href="#SHELL">The Shell</a></dt>
<dd>
<dl>
<dt>8.1 <a href="#SHELL-USERS">Users</a></dt>
<dd>
<dl>
<dt>8.1.1 <a href="#AEN2678">Logging In</a></dt>
<dt>8.1.2 <a href="#AEN2693">Root: The Superuser</a></dt>
</dl>
</dd>
<dt>8.2 <a href="#SHELL-COMMAND-LINE">The Command Line</a></dt>
<dd>
<dl>
<dt>8.2.1 <a href="#SHELL-COMMAND-LINE-RUNNING">Running Programs</a></dt>
<dt>8.2.2 <a href="#SHELL-COMMAND-LINE-WILDCARD">Wildcard Matching</a></dt>
<dt>8.2.3 <a href="#SHELL-COMMAND-LINE-PIPING">Input/Output Redirection and
Piping</a></dt>
</dl>
</dd>
<dt>8.3 <a href="#SHELL-BASH">The Bourne Again Shell (bash)</a></dt>
<dd>
<dl>
<dt>8.3.1 <a href="#SHELL-BASH-ENVIRONMENT">Environment Variables</a></dt>
<dt>8.3.2 <a href="#SHELL-BASH-TAB">Tab Completion</a></dt>
</dl>
</dd>
<dt>8.4 <a href="#SHELL-VT">Virtual Terminals</a></dt>
<dd>
<dl>
<dt>8.4.1 <a href="#AEN3024">Screen</a></dt>
</dl>
</dd>
</dl>
</dd>
<dt>9 <a href="#FILESYSTEM-STRUCTURE">Filesystem Structure</a></dt>
<dd>
<dl>
<dt>9.1 <a href="#FILESYSTEM-STRUCTURE-OWNERSHIP">Ownership</a></dt>
<dt>9.2 <a href="#FILESYSTEM-STRUCTURE-PERMISSIONS">Permissions</a></dt>
<dt>9.3 <a href="#FILESYSTEM-STRUCTURE-LINKS">Links</a></dt>
<dt>9.4 <a href="#FILESYSTEM-STRUCTURE-MOUNTING">Mounting Devices</a></dt>
<dd>
<dl>
<dt>9.4.1 <a href="#AEN3319"><tt class="FILENAME">fstab</tt></a></dt>
<dt>9.4.2 <a href="#AEN3340"><tt class="COMMAND">mount</tt> and <tt
class="COMMAND">umount</tt></a></dt>
</dl>
</dd>
<dt>9.5 <a href="#FILESYSTEM-STRUCTURE-NFS">NFS Mounts</a></dt>
</dl>
</dd>
<dt>10 <a href="#FILE-COMMANDS">Handling Files and Directories</a></dt>
<dd>
<dl>
<dt>10.1 <a href="#FILE-COMMANDS-NAVIGATION">Navigation : <tt class="COMMAND">ls</tt>,
<tt class="COMMAND">cd</tt>, and <tt class="COMMAND">pwd</tt></a></dt>
<dd>
<dl>
<dt>10.1.1 <a href="#AEN3398"><tt class="COMMAND">ls</tt></a></dt>
<dt>10.1.2 <a href="#AEN3436"><tt class="COMMAND">cd</tt></a></dt>
<dt>10.1.3 <a href="#AEN3463"><tt class="COMMAND">pwd</tt></a></dt>
</dl>
</dd>
<dt>10.2 <a href="#FILE-COMMANDS-PAGERS">Pagers: <tt class="COMMAND">more</tt>, <tt
class="COMMAND">less</tt>, and <tt class="COMMAND">most</tt></a></dt>
<dd>
<dl>
<dt>10.2.1 <a href="#AEN3491"><tt class="COMMAND">more</tt></a></dt>
<dt>10.2.2 <a href="#AEN3518"><tt class="COMMAND">less</tt></a></dt>
<dt>10.2.3 <a href="#AEN3539"><tt class="COMMAND">most</tt></a></dt>
</dl>
</dd>
<dt>10.3 <a href="#FILE-COMMANDS-OUTPUT">Simple Output: <tt class="COMMAND">cat</tt> and
<tt class="COMMAND">echo</tt></a></dt>
<dd>
<dl>
<dt>10.3.1 <a href="#AEN3559"><tt class="COMMAND">cat</tt></a></dt>
<dt>10.3.2 <a href="#AEN3603"><tt class="COMMAND">echo</tt></a></dt>
</dl>
</dd>
<dt>10.4 <a href="#FILE-COMMANDS-CREATION">Creation: <tt class="COMMAND">touch</tt> and
<tt class="COMMAND">mkdir</tt></a></dt>
<dd>
<dl>
<dt>10.4.1 <a href="#AEN3619"><tt class="COMMAND">touch</tt></a></dt>
<dt>10.4.2 <a href="#AEN3639"><tt class="COMMAND">mkdir</tt></a></dt>
</dl>
</dd>
<dt>10.5 <a href="#FILE-COMMANDS-COPYMOVE">Copy and Move</a></dt>
<dd>
<dl>
<dt>10.5.1 <a href="#FILE-COMMANDS-COPYMOVE-CP"><tt class="COMMAND">cp</tt></a></dt>
<dt>10.5.2 <a href="#AEN3712"><tt class="COMMAND">mv</tt></a></dt>
</dl>
</dd>
<dt>10.6 <a href="#FILE-COMMANDS-DELETION">Deletion: <tt class="COMMAND">rm</tt> and <tt
class="COMMAND">rmdir</tt></a></dt>
<dd>
<dl>
<dt>10.6.1 <a href="#AEN3733"><tt class="COMMAND">rm</tt></a></dt>
<dt>10.6.2 <a href="#AEN3764"><tt class="COMMAND">rmdir</tt></a></dt>
</dl>
</dd>
<dt>10.7 <a href="#FILE-COMMANDS-LINK">Aliasing files with <tt
class="COMMAND">ln</tt></a></dt>
</dl>
</dd>
<dt>11 <a href="#PROCESS-CONTROL">Process Control</a></dt>
<dd>
<dl>
<dt>11.1 <a href="#PROCESS-CONTROL-BACKGROUNDING">Backgrounding</a></dt>
<dt>11.2 <a href="#PROCESS-CONTROL-FOREGROUNDING">Foregrounding</a></dt>
<dt>11.3 <a href="#PROCESS-CONTROL-PS"><tt class="COMMAND">ps</tt></a></dt>
<dt>11.4 <a href="#PROCESS-CONTROL-KILL"><tt class="COMMAND">kill</tt></a></dt>
<dt>11.5 <a href="#PROCESS-CONTROL-TOP"><tt class="COMMAND">top</tt></a></dt>
</dl>
</dd>
<dt>12 <a href="#ESSENTIAL-SYSADMIN">Essential System Administration</a></dt>
<dd>
<dl>
<dt>12.1 <a href="#ESSENTIAL-SYSADMIN-USERS">Users and Groups</a></dt>
<dd>
<dl>
<dt>12.1.1 <a href="#ESSENTIAL-SYSADMIN-USERS-SCRIPTS">Supplied Scripts</a></dt>
<dt>12.1.2 <a href="#ESSENTIAL-SYSADMIN-USERS-PASSWDS">Changing Passwords</a></dt>
<dt>12.1.3 <a href="#ESSENTIAL-SYSADMIN-USERS-CHANGING">Changing User
Information</a></dt>
</dl>
</dd>
<dt>12.2 <a href="#ESSENTIAL-SYSADMIN-HARDUSERS">Users and Groups, the Hard Way</a></dt>
<dt>12.3 <a href="#ESSENTIAL-SYSADMIN-SHUTDOWN">Shutting Down Properly</a></dt>
</dl>
</dd>
<dt>13 <a href="#BASIC-NETWORK-COMMANDS">Basic Network Commands</a></dt>
<dd>
<dl>
<dt>13.1 <a href="#BASIC-NETWORK-COMMANDS-PING"><tt class="COMMAND">ping</tt></a></dt>
<dt>13.2 <a href="#BASIC-NETWORK-COMMANDS-TRACEROUTE"><tt
class="COMMAND">traceroute</tt></a></dt>
<dt>13.3 <a href="#BASIC-NETWORK-COMMANDS-DNS">DNS Tools</a></dt>
<dd>
<dl>
<dt>13.3.1 <a href="#AEN4475"><tt class="COMMAND">host</tt></a></dt>
<dt>13.3.2 <a href="#AEN4487"><tt class="COMMAND">nslookup</tt></a></dt>
<dt>13.3.3 <a href="#AEN4496"><tt class="COMMAND">dig</tt></a></dt>
</dl>
</dd>
<dt>13.4 <a href="#BASIC-NETWORK-COMMANDS-FINGER"><tt
class="COMMAND">finger</tt></a></dt>
<dt>13.5 <a href="#BASIC-NETWORK-COMMANDS-TELNET"><tt
class="COMMAND">telnet</tt></a></dt>
<dd>
<dl>
<dt>13.5.1 <a href="#AEN4593">The other use of telnet</a></dt>
</dl>
</dd>
<dt>13.6 <a href="#BASIC-NETWORK-COMMANDS-SSH">The Secure shell</a></dt>
<dt>13.7 <a href="#BASIC-NETWORK-COMMANDS-EMAIL">email</a></dt>
<dd>
<dl>
<dt>13.7.1 <a href="#BASIC-NETWORK-COMMANDS-EMAIL-PINE"><tt
class="COMMAND">pine</tt></a></dt>
<dt>13.7.2 <a href="#BASIC-NETWORK-COMMANDS-EMAIL-ELM"><tt
class="COMMAND">elm</tt></a></dt>
<dt>13.7.3 <a href="#BASIC-NETWORK-COMMANDS-EMAIL-MUTT"><tt
class="COMMAND">mutt</tt></a></dt>
<dt>13.7.4 <a href="#BASIC-NETWORK-COMMANDS-EMAIL-NAIL"><tt
class="COMMAND">nail</tt></a></dt>
</dl>
</dd>
<dt>13.8 <a href="#BASIC-NETWORK-COMMANDS-WEB">Browsers</a></dt>
<dd>
<dl>
<dt>13.8.1 <a href="#AEN4776"><tt class="COMMAND">lynx</tt></a></dt>
<dt>13.8.2 <a href="#AEN4813"><tt class="COMMAND">links</tt></a></dt>
<dt>13.8.3 <a href="#AEN4831"><tt class="COMMAND">wget</tt></a></dt>
</dl>
</dd>
<dt>13.9 <a href="#BASIC-NETWORK-COMMANDS-FTP">FTP Clients</a></dt>
<dd>
<dl>
<dt>13.9.1 <a href="#AEN4871"><tt class="COMMAND">ftp</tt></a></dt>
<dt>13.9.2 <a href="#BASIC-NETWORK-COMMANDS-FTP-NCFTP"><tt
class="COMMAND">ncftp</tt></a></dt>
</dl>
</dd>
<dt>13.10 <a href="#BASIC-NETWORK-COMMANDS-TALK">Talking to Other People</a></dt>
<dd>
<dl>
<dt>13.10.1 <a href="#AEN4989"><tt class="COMMAND">wall</tt></a></dt>
<dt>13.10.2 <a href="#AEN5006"><tt class="COMMAND">talk</tt></a></dt>
<dt>13.10.3 <a href="#AEN5033"><tt class="COMMAND">ytalk</tt></a></dt>
</dl>
</dd>
</dl>
</dd>
<dt>14 <a href="#SECURITY">Security</a></dt>
<dd>
<dl>
<dt>14.1 <a href="#SECURITY-DISABLE">Disabling Services</a></dt>
<dd>
<dl>
<dt>14.1.1 <a href="#AEN5081">Services started from <tt
class="COMMAND">inetd</tt></a></dt>
<dt>14.1.2 <a href="#AEN5102">Services started from init scripts</a></dt>
</dl>
</dd>
<dt>14.2 <a href="#SECURITY-HOST">Host Access Control</a></dt>
<dd>
<dl>
<dt>14.2.1 <a href="#SECURITY-HOST-IPTABLES"><tt class="COMMAND">iptables</tt></a></dt>
<dt>14.2.2 <a href="#SECURITY-HOST-TCPWRAPPERS"><tt
class="COMMAND">tcpwrappers</tt></a></dt>
</dl>
</dd>
<dt>14.3 <a href="#SECURITY-CURRENT">Keeping Current</a></dt>
<dd>
<dl>
<dt>14.3.1 <a href="#SECURITY-CURRENT-LIST"><var class="LITERAL">slackware-security</var>
mailing list</a></dt>
<dt>14.3.2 <a href="#SECURITY-CURRENT-PATCHES">The <tt class="FILENAME">/patches</tt>
directory</a></dt>
</dl>
</dd>
</dl>
</dd>
<dt>15 <a href="#ARCHIVE-FILES">Archive Files</a></dt>
<dd>
<dl>
<dt>15.1 <a href="#ARCHIVE-FILES-GZIP"><tt class="COMMAND">gzip</tt></a></dt>
<dt>15.2 <a href="#ARCHIVE-FILES-BZIP2"><tt class="COMMAND">bzip2</tt></a></dt>
<dt>15.3 <a href="#ARCHIVE-FILES-TAR"><tt class="COMMAND">tar</tt></a></dt>
<dt>15.4 <a href="#ARCHIVE-FILES-ZIP"><tt class="COMMAND">zip</tt></a></dt>
</dl>
</dd>
<dt>16 <a href="#VI">Vi</a></dt>
<dd>
<dl>
<dt>16.1 <a href="#VI-STARTING">Starting vi</a></dt>
<dt>16.2 <a href="#VI-MODES">Modes</a></dt>
<dd>
<dl>
<dt>16.2.1 <a href="#VI-MODES-COMMAND-MODE">Command Mode</a></dt>
<dt>16.2.2 <a href="#VI-MODES-INSET-MODE">Insert Mode</a></dt>
</dl>
</dd>
<dt>16.3 <a href="#VI-OPENING-FILES">Opening Files</a></dt>
<dt>16.4 <a href="#VI-SAVING-FILES">Saving Files</a></dt>
<dt>16.5 <a href="#VI-QUITTING-VI">Quitting vi</a></dt>
<dt>16.6 <a href="#VI-CONFIGURATION">vi Configuration</a></dt>
<dt>16.7 <a href="#VI-KEYS">Vi Keys</a></dt>
</dl>
</dd>
<dt>17 <a href="#EMACS">Emacs</a></dt>
<dd>
<dl>
<dt>17.1 <a href="#EMACS-STARTING">Starting emacs</a></dt>
<dd>
<dl>
<dt>17.1.1 <a href="#EMACS-COMMAND-KEYS">Command Keys</a></dt>
</dl>
</dd>
<dt>17.2 <a href="#EMACS-BUFFERS">Buffers</a></dt>
<dt>17.3 <a href="#EMACS-MODES">Modes</a></dt>
<dd>
<dl>
<dt>17.3.1 <a href="#EMACS-OPENING-FILES">Opening files</a></dt>
</dl>
</dd>
<dt>17.4 <a href="#EMACS-BASIC-EDITING">Basic Editing</a></dt>
<dt>17.5 <a href="#EMACS-SAVING-FILES">Saving Files</a></dt>
<dd>
<dl>
<dt>17.5.1 <a href="#EMACS-QUITING">Quitting Emacs</a></dt>
</dl>
</dd>
</dl>
</dd>
<dt>18 <a href="#PACKAGE-MANAGEMENT">Slackware Package Management</a></dt>
<dd>
<dl>
<dt>18.1 <a href="#PACKAGE-MANAGEMENT-OVERVIEW">Overview of Package Format</a></dt>
<dt>18.2 <a href="#PACKAGE-MANAGEMENT-PACKAGE-UTILITIES">Package Utilities</a></dt>
<dd>
<dl>
<dt>18.2.1 <a href="#PACKAGE-MANAGEMENT-PACKAGE-UTILITIES-PKGTOOL">pkgtool</a></dt>
<dt>18.2.2 <a href="#PACKAGE-MANAGEMENT-PACKAGE-UTILITIES-INSTALLPKG">installpkg</a></dt>
<dt>18.2.3 <a href="#PACKAGE-MANAGEMENT-PACKAGE-UTILITIES-REMOVEPKG">removepkg</a></dt>
<dt>18.2.4 <a href="#PACKAGE-MANAGEMENT-PACKAGE-UTILITIES-UPGRADEPKG">upgradepkg</a></dt>
<dt>18.2.5 <a href="#PACKAGE-MANAGEMENT-PACKAGE-UTILITIES-RPM"><tt
class="COMMAND">rpm2tgz</tt>/<tt class="COMMAND">rpm2targz</tt></a></dt>
</dl>
</dd>
<dt>18.3 <a href="#PACKAGE-MANAGEMENT-MAKING-PACKAGES">Making Packages</a></dt>
<dd>
<dl>
<dt>18.3.1 <a href="#PACKAGE-MANAGEMENT-EXPLODEPKG"><tt
class="COMMAND">explodepkg</tt></a></dt>
<dt>18.3.2 <a href="#PACKAGE-MANAGEMENT-MAKEPKG"><tt
class="COMMAND">makepkg</tt></a></dt>
<dt>18.3.3 <a href="#PACKAGE-MANAGEMENT-SLACKBUILD-SCRIPTS">SlackBuild Scripts</a></dt>
</dl>
</dd>
<dt>18.4 <a href="#PACKAGE-MANAGEMENT-MAKING-TAGS-AND-TAGFILES">Making Tags and Tagfiles
(for setup)</a></dt>
</dl>
</dd>
<dt>19 <a href="#ZIPSLACK">ZipSlack</a></dt>
<dd>
<dl>
<dt>19.1 <a href="#ZIPSLACK-WHAT">What is ZipSlack?</a></dt>
<dd>
<dl>
<dt>19.1.1 <a href="#ZIPSLACK-ADVANTAGES">Advantages</a></dt>
<dt>19.1.2 <a href="#ZIPSLACK-DISADVANTAGES">Disadvantages</a></dt>
</dl>
</dd>
<dt>19.2 <a href="#ZIPSLACK-GETTING">Getting ZipSlack</a></dt>
<dd>
<dl>
<dt>19.2.1 <a href="#ZIPSLACK-INSTALLATION">Installation</a></dt>
</dl>
</dd>
<dt>19.3 <a href="#ZIPSLACK-BOOTING">Booting ZipSlack</a></dt>
</dl>
</dd>
<dt><a href="#GLOSSARY">Glossary</a></dt>
<dt>A. <a href="#GPL">The GNU General Public License</a></dt>
<dd>
<dl>
<dt>A.1. <a href="#AEN7088">Preamble</a></dt>
<dt>A.2. <a href="#AEN7098">TERMS AND CONDITIONS</a></dt>
<dt>A.3. <a href="#AEN7162">How to Apply These Terms to Your New Programs</a></dt>
</dl>
</dd>
</dl>
</div>
<div class="LOT">
<dl class="LOT">
<dt><b>List of Tables</b></dt>
<dt>2-1. <a href="#AEN409">Man Page Sections</a></dt>
<dt>3-1. <a href="#AEN661">Slackware Linux, Inc. Contact Information</a></dt>
<dt>3-2. <a href="#AEN706">System Requirements</a></dt>
<dt>3-3. <a href="#AEN746">Software Series</a></dt>
<dt>9-1. <a href="#AEN3142">Octal Permission Values</a></dt>
<dt>13-1. <a href="#AEN4883"><tt class="COMMAND">ftp</tt> commands</a></dt>
<dt>16-1. <a href="#AEN5773">Movement</a></dt>
<dt>16-2. <a href="#AEN5808">Editing</a></dt>
<dt>16-3. <a href="#AEN5848">Searching</a></dt>
<dt>16-4. <a href="#AEN5882">Saving and Quitting</a></dt>
<dt>17-1. <a href="#TABLE-EMACS-BASIC-EDITING">Basic Emacs Editing Commands</a></dt>
<dt>18-1. <a href="#AEN6446"><tt class="COMMAND">installpkg</tt> Options</a></dt>
<dt>18-2. <a href="#AEN6491"><tt class="COMMAND">removepkg</tt> Options</a></dt>
<dt>18-3. <a href="#AEN6621">Tagfile Status Options</a></dt>
</dl>
</div>
<div class="LOT">
<dl class="LOT">
<dt><b>List of Figures</b></dt>
<dt>4-1. <a href="#SYSTEM-CONFIGURATION-MAKE-MENUCONFIG">Kernel Configuration
Menu</a></dt>
<dt>6-1. <a href="#X-WINDOW-SYSTEM-1"><tt class="COMMAND">xorgconfig</tt> Mouse
Configuration</a></dt>
<dt>6-2. <a href="#X-WINDOW-SYSTEM-2"><tt class="COMMAND">xorgconfig</tt> Horizontal
Sync</a></dt>
<dt>6-3. <a href="#X-WINDOW-SYSTEM-3"><tt class="COMMAND">xorgconfig</tt> Vertical
Sync</a></dt>
<dt>6-4. <a href="#X-WINDOW-SYSTEM-4"><tt class="COMMAND">xorgconfig</tt> Video
Card</a></dt>
<dt>6-5. <a href="#FIG-X-WINDOW-SYSTEM-XWMCONFIG">Desktop Configuration with <tt
class="COMMAND">xorgconfig</tt></a></dt>
<dt>7-1. <a href="#BOOTING-SETUP-LILO"><tt class="COMMAND">liloconfig</tt></a></dt>
<dt>7-2. <a href="#BOOTING-LILO-EXPERT"><tt class="COMMAND">liloconfig</tt> Expert
Menu</a></dt>
<dt>11-1. <a href="#FIG-PROCESS-CONTROL-PS-SHORT">Basic <tt class="COMMAND">ps</tt>
output</a></dt>
<dt>13-1. <a href="#FIG-BASIC-NETWORK-COMMANDS-TELNET-WEB">Telnetting to a
webserver</a></dt>
<dt>13-2. <a href="#FIG-BASIC-NETWORK-COMMANDS-EMAIL-PINE">The Pine main menu</a></dt>
<dt>13-3. <a href="#FIG-BASIC-NETWORK-COMMANDS-EMAIL-ELM">Elm main screen</a></dt>
<dt>13-4. <a href="#FIG-BASIC-NETWORK-COMMANDS-EMAIL-MUTT">Mutt main screen</a></dt>
<dt>13-5. <a href="#FIG-BASIC-NETWORK-COMMANDS-WEB-LYNX">Lynx default start page</a></dt>
<dt>13-6. <a href="#FIG-BASIC-NETWORK-COMMANDS-WEB-LINKS">Links, with the file menu
open</a></dt>
<dt>13-7. <a href="#FIG-BASIC-NETWORK-COMMANDS-TALK-TALK">Two users in a <tt
class="COMMAND">talk</tt> session</a></dt>
<dt>13-8. <a href="#FIG-BASIC-NETWORK-COMMANDS-TALK-YTALK">Two users in a <tt
class="COMMAND">ytalk</tt> session</a></dt>
<dt>16-1. <a href="#FIG-VI-VIM-SPLITEDIT">A vi session.</a></dt>
<dt>18-1. <a href="#PKGTOOL-MAIN-MENU">Pkgtool's main menu.</a></dt>
<dt>18-2. <a href="#PKGTOOL-VIEW-MODE">Pkgtool view mode</a></dt>
</dl>
</div>
<div class="LOT">
<dl class="LOT">
<dt><b>List of Examples</b></dt>
<dt>8-1. <a href="#EX-SHELL-BASH-ENVIRONMENT">Listing Environment Variables with <tt
class="COMMAND">set</tt></a></dt>
</dl>
</div>
<div class="PREFACE">
<hr />
<h1><a id="BOOK-PREFACE" name="BOOK-PREFACE"></a>Preface</h1>
<h2 class="BRIDGEHEAD"><a id="PREFACE-AUDIENCE" name="PREFACE-AUDIENCE"></a>Intended
Audience</h2>
<p>The Slackware Linux operating system is a powerful platform for Intel-based computers.
It is designed to be stable, secure, and functional as both a high-end server and
powerful workstation.</p>
<p>This book is designed to get you started with the Slackware Linux operating system.
It's not meant to cover every single aspect of the distribution, but rather to show what
it is capable of and give you a basic working knowledge of the system.</p>
<p>As you gain experience with Slackware Linux, we hope you find this book to be a handy
reference. We also hope you'll lend it to all of your friends when they come asking about
that cool Slackware Linux operating system you're running.</p>
<p>While this book may not an edge-of-your-seat novel, we certainly tried to make it as
entertaining as possible. With any luck, we'll get a movie deal. Of course, we also hope
you are able to learn from it and find it useful.</p>
<p>And now, on with the show.</p>
<h2 class="BRIDGEHEAD"><a id="PREFACE-CHANGES" name="PREFACE-CHANGES"></a>Changes from
the First Edition</h2>
<p>This second edition is the culmination of years of hard work by the dedicated members
of the Slackware Documentation Project. The following are the major changes in this new
edition:</p>
<ul>
<li>
<p><a href="#INSTALLATION">Chapter 3</a>, Installation, has been modified with new
screenshots of the installer, and reflects changes in disk-sets, and CD installation.</p>
</li>
<li>
<p><a href="#SYSTEM-CONFIGURATION">Chapter 4</a>, System Configuration, has been updated
with new information about Linux 2.6.x kernels.</p>
</li>
<li>
<p><a href="#NETWORK-CONFIGURATION">Chapter 5</a>, Network Configuration, has been
expanded with further explanation of Samba, NFS, and DHCP. A section on wireless
networking has also been added. This chapter now reflects major changes in how Slackware
handles network setup.</p>
</li>
<li>
<p><a href="#X-WINDOW-SYSTEM">Chapter 6</a>, X Window System, has been substantially
rewritten for Xorg based systems. This chapter now also covers the xdm graphical login
manager.</p>
</li>
<li>
<p><a href="#BASIC-NETWORK-COMMANDS">Chapter 13</a>, Basic Network Commands, has been
enhanced with information about additional network utilities.</p>
</li>
<li>
<p><a href="#SECURITY">Chapter 14</a>, Security, is a new chapter with this edition. It
explains how to keep a Slackware Linux system secure.</p>
</li>
<li>
<p><a href="#EMACS">Chapter 17</a>, Emacs, is a new chapter with this edition. It
describes how to use Emacs, a powerful editor for Unix.</p>
</li>
<li>
<p><a href="#PACKAGE-MANAGEMENT">Chapter 18</a>, Package Management, has been updated
with information about SlackBuild scripts.</p>
</li>
<li>
<p>There are many other changes, both minor and major, to reflect changes in Slackware as
it has matured.</p>
</li>
</ul>
<h2 class="BRIDGEHEAD"><a id="PREFACE-ORGANIZATION"
name="PREFACE-ORGANIZATION"></a>Organization of this Book</h2>
<div class="VARIABLELIST">
<dl>
<dt><a href="#INTRODUCTION">Chapter 1</a>, Introduction</dt>
<dd>
<p>Provides introductory material on Linux, Slackware, and the Open Source and Free
Software Movements.</p>
</dd>
<dt><a href="#HELP">Chapter 2</a>, Help</dt>
<dd>
<p>Describes the help resources available on a Slackware Linux system and online.</p>
</dd>
<dt><a href="#INSTALLATION">Chapter 3</a>, Installation</dt>
<dd>
<p>Describes the installation process step-by-step with screenshots to provide an
illustrative walk-through.</p>
</dd>
<dt><a href="#SYSTEM-CONFIGURATION">Chapter 4</a>, System Configuration</dt>
<dd>
<p>Describes the important configuration files and covers kernel recompilation.</p>
</dd>
<dt><a href="#NETWORK-CONFIGURATION">Chapter 5</a>, Network Configuration</dt>
<dd>
<p>Describes how to connect a Slackware Linux machine to a network. Covers TCP/IP,
PPP/dial-up, wireless networking, and more.</p>
</dd>
<dt><a href="#X-WINDOW-SYSTEM">Chapter 6</a>, The X Window System</dt>
<dd>
<p>Describes how to setup and use the graphical X Window System in Slackware.</p>
</dd>
<dt><a href="#BOOTING">Chapter 7</a>, Booting</dt>
<dd>
<p>Describes the process by which a computer boots into Slackware Linux. Also covers
dual-booting with Microsoft Windows operating systems.</p>
</dd>
<dt><a href="#SHELL">Chapter 8</a>, The Shell</dt>
<dd>
<p>Describes the powerful command line interface for Linux.</p>
</dd>
<dt><a href="#FILESYSTEM-STRUCTURE">Chapter 9</a>, Filesystem Structure</dt>
<dd>
<p>Describes the filesystem structure, including file ownership, permission, and
linking.</p>
</dd>
<dt><a href="#FILE-COMMANDS">Chapter 10</a>, Handling Files and Directories</dt>
<dd>
<p>Describes the commands used to manipulate files and directories from the command line
interface.</p>
</dd>
<dt><a href="#PROCESS-CONTROL">Chapter 11</a>, Process Control</dt>
<dd>
<p>Describes the powerful Linux process management commands used to manage multiple
running applications.</p>
</dd>
<dt><a href="#ESSENTIAL-SYSADMIN">Chapter 12</a>, Essential System Administration</dt>
<dd>
<p>Describes basic system administration tasks such as adding and removing users,
shutting down the system properly, and more.</p>
</dd>
<dt><a href="#BASIC-NETWORK-COMMANDS">Chapter 13</a>, Basic Network Commands</dt>
<dd>
<p>Describes the collection of network clients included with Slackware.</p>
</dd>
<dt><a href="#SECURITY">Chapter 14</a>, Security</dt>
<dd>
<p>Describes many different tools available to help keep your Slackware system secure,
including <tt class="COMMAND">iptables</tt> and <tt class="COMMAND">tcpwrappers</tt>.</p>
</dd>
<dt><a href="#ARCHIVE-FILES">Chapter 15</a>, Archive Files</dt>
<dd>
<p>Describes the different compression and archive utilities available for Linux.</p>
</dd>
<dt><a href="#VI">Chapter 16</a>, vi</dt>
<dd>
<p>Describes the powerful <tt class="COMMAND">vi</tt> text editor.</p>
</dd>
<dt><a href="#EMACS">Chapter 17</a>, Emacs</dt>
<dd>
<p>Describes the powerful <tt class="COMMAND">Emacs</tt> text editor.</p>
</dd>
<dt><a href="#PACKAGE-MANAGEMENT">Chapter 18</a>, Slackware Package Management</dt>
<dd>
<p>Describes the Slackware package utilities and the process used to create custom
packages and tagfiles.</p>
</dd>
<dt><a href="#ZIPSLACK">Chapter 19</a>, ZipSlack</dt>
<dd>
<p>Describes the ZipSlack version of Linux that can be used from Windows without
requiring an installation.</p>
</dd>
<dt><a href="#GPL">Appendix A</a>, The GNU General Public License</dt>
<dd>
<p>Describes the license terms under which Slackware Linux and this book can be copied
and distributed.</p>
</dd>
</dl>
</div>
<h2 class="BRIDGEHEAD"><a id="PREFACE-CONV" name="PREFACE-CONV"></a>Conventions used in
this book</h2>
<p>To provide a consistent and easy to read text, several conventions are followed
throughout the book.</p>
<h3 class="BRIDGEHEAD"><a id="PREFACE-CONV-TYPOGRAPHIC"
name="PREFACE-CONV-TYPOGRAPHIC"></a>Typographic Conventions</h3>
<div class="VARIABLELIST">
<dl>
<dt><span class="emphasis"><i class="EMPHASIS">Italic</i></span></dt>
<dd>
<p>An <span class="emphasis"><i class="EMPHASIS">italic</i></span> font is used for
commands, emphasized text, and the first usage of technical terms.</p>
</dd>
<dt><var class="VARNAME">Monospace</var></dt>
<dd>
<p>A <var class="VARNAME">monospaced</var> font is used for error messages, commands,
environment variables, names of ports, hostnames, user names, group names, device names,
variables, and code fragments.</p>
</dd>
<dt><b class="APPLICATION">Bold</b></dt>
<dd>
<p>A <b class="APPLICATION">bold</b> font is used for user input in examples.</p>
</dd>
</dl>
</div>
<h3 class="BRIDGEHEAD"><a id="PREFACE-CONV-COMMANDS"
name="PREFACE-CONV-COMMANDS"></a>User Input</h3>
<p>Keys are shown in <b class="KEYCAP">bold</b> to stand out from other text. Key
combinations that are meant to be typed simultaneously are shown with `<var
class="LITERAL">+</var>' between the keys, such as:</p>
<p><b class="KEYCAP">Ctrl</b>+<b class="KEYCAP">Alt</b>+<b class="KEYCAP">Del</b></p>
<p>Meaning the user should type the <b class="KEYCAP">Ctrl</b>, <b
class="KEYCAP">Alt</b>, and <b class="KEYCAP">Del</b> keys at the same time.</p>
<p>Keys that are meant to be typed in sequence will be separated with commas, for
example:</p>
<p><b class="KEYCAP">Ctrl</b>+<b class="KEYCAP">X</b>, <b class="KEYCAP">Ctrl</b>+<b
class="KEYCAP">S</b></p>
<p>Would mean that the user is expected to type the <b class="KEYCAP">Ctrl</b> and <b
class="KEYCAP">X</b> keys simultaneously and then to type the <b class="KEYCAP">Ctrl</b>
and <b class="KEYCAP">S</b> keys simultaneously.</p>
<h3 class="BRIDGEHEAD"><a id="PREFACE-CONV-EXAMPLES"
name="PREFACE-CONV-EXAMPLES"></a>Examples</h3>
<p>Examples starting with <tt class="DEVICENAME">E:\></tt> indicate a <span
class="TRADEMARK">MS-DOS</span>® command. Unless otherwise noted, these commands may
be executed from a “Command Prompt” window in a modern <span
class="TRADEMARK">Microsoft</span>® <span class="TRADEMARK">Windows</span>®
environment.</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">D:\></samp> <kbd class="USERINPUT">rawrite a: bare.i</kbd>
</pre>
</td>
</tr>
</table>
<p>Examples starting with <samp class="PROMPT">#</samp> indicate a command that must be
invoked as the superuser in Slackware. You can login as <tt class="USERNAME">root</tt> to
type the command, or login as your normal account and use <span
class="CITEREFENTRY"><span class="REFENTRYTITLE">su</span>(1)</span> to gain superuser
privileges.</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">#</samp> <kbd class="USERINPUT">dd if=bare.i of=/dev/fd0</kbd>
</pre>
</td>
</tr>
</table>
<p>Examples starting with <samp class="PROMPT">%</samp> indicate a command that should be
invoked from a normal user account. Unless otherwise noted, C-shell syntax is used for
setting environment variables and other shell commands.</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">top</kbd>
</pre>
</td>
</tr>
</table>
<h2 class="BRIDGEHEAD"><a id="PREFACE-ACKNOWLEDGEMENTS"
name="PREFACE-ACKNOWLEDGEMENTS"></a>Acknowledgments</h2>
<p>This project is the accumulation of months of work by many dedicated individuals. It
would not have been possible for me to produce this work in a vacuum. Many people deserve
our thanks for their selfless acts: Keith Keller for his work on wireless networking,
Joost Kremers for his great work in single-handedly writing the emacs section, Simon
Williams for the security chapter, Jurgen Phillippaerts for basic networking commands,
Cibao Cu Ali G Colibri for the inspiration and a good kick in the pants. Countless others
have sent in suggestions and fixes. An incomplete list includes: Jacob Anhoej, John Yast,
Sally Welch, Morgan Landry, and Charlie Law. I'd also like to thank Keith Keller for
hosting the mailing list for this project, as well as Carl Inglis for the initial web
hosting. Last but not least, I'd like to thank Patrick J. Volkerding for Slackware Linux,
and David Cantrell, Logan Johnson, and Chris Lumens for Slackware Linux Essentials 1st
Edition. Without their initial framework, none of this would have ever happened. Many
others have contributed in small and large ways to this project and have not been listed.
I hope they will forgive me for a poor memory.</p>
<p>Alan Hicks, May 2005</p>
</div>
<div class="CHAPTER">
<hr />
<h1><a id="INTRODUCTION" name="INTRODUCTION"></a>Chapter 1 An Introduction to Slackware
Linux</h1>
<div class="SECT1">
<h2 class="SECT1"><a id="INTRODUCTION-LINUX" name="INTRODUCTION-LINUX">1.1 What is
Linux?</a></h2>
<p>Linus Torvalds started Linux, an operating system kernel, as a personal project in
1991. He started the project because he wanted to run a Unix-based operating system
without spending a lot of money. In addition, he wanted to learn the ins and outs of the
386 processor. Linux was released free of charge to the public so that anyone could study
it and make improvements under the General Public License. (See <a
href="#INTRODUCTION-OPENSOURCE">Section 1.3</a> and <a href="#GPL">Appendix A</a> for an
explanation of the license.) Today, Linux has grown into a major player in the operating
system market. It has been ported to run on a variety of system architectures, including
HP/Compaq's Alpha, Sun's SPARC and UltraSPARC, and Motorola's PowerPC chips (through
Apple Macintosh and IBM RS/6000 computers.) Hundreds, if not thousands, of programmers
all over the world now develop Linux. It runs programs like Sendmail, Apache, and BIND,
which are very popular software used to run Internet servers. It's important to remember
that the term “Linux” really refers to the kernel - the core of the operating
system. This core is responsible for controlling your computer's processor, memory, hard
drives, and peripherals. That's all Linux really does: It controls the operations of your
computer and makes sure that all of its programs behave. Various companies and
individuals bundle the kernel and various programs together to make an operating system.
We call each bundle a Linux distribution.</p>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="INTRODUCTION-LINUX-GNU" name="INTRODUCTION-LINUX-GNU">1.1.1 A
Word on GNU</a></h3>
<p>The Linux kernel project began as a solo endeavor by Linus Torvalds in 1991, but as
Isaac Newton once said, “If I have seen further, it is by standing on the shoulders
of giants.” When Linus Torvalds began the kernel the Free Software Foundation had
already established the idea of collaborative software. They entitled their effort GNU, a
recursive acronym that means simply “GNU's Not Unix”. GNU software ran atop
the Linux kernel from day 1. Their compiler <tt class="COMMAND">gcc</tt> was used to
compile the kernel. Today many GNU tools from <tt class="COMMAND">gcc</tt> to <tt
class="COMMAND">gnutar</tt> are still at the basis of every major Linux distribution. For
this reason many of the Free Software Foundation's proponents fervently state that their
work should be given the same credit as the Linux kernel. They strongly suggest that all
Linux distributions should refer to themselves as GNU/Linux distributions.</p>
<p>This is the topic of many flamewars, surpassed only by the ancient vi versus emacs
holy war. The purpose of this book is not to fan the fires of this heated discussion, but
rather to clarify the terminology for neophytes. When one sees GNU/Linux it means a Linux
distribution. When one sees Linux they can either be referring to the kernel, or to a
distribution. It can be rather confusing. Typically the term GNU/Linux isn't used because
it's a mouth full.</p>
</div>
</div>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="INTRODUCTION-SLACKWARE" name="INTRODUCTION-SLACKWARE">1.2 What
is Slackware?</a></h2>
<p>Slackware, started by Patrick Volkerding in late 1992, and initially released to the
world on July 17, 1993, was the first Linux distribution to achieve widespread use.
Volkerding first learned of Linux when he needed an inexpensive LISP interpreter for a
project. One of the few distributions available at the time was SLS Linux from Soft
Landing Systems. Volkerding used SLS Linux, fixing bugs as he found them. Eventually, he
decided to merge all of these bugfixes into his own private distribution that he and his
friends could use. This private distribution quickly gained popularity, so Volkerding
decided to name it Slackware and make it publicly available. Along the way, Patrick added
new things to Slackware; a user friendly installation program based on a menuing system,
as well as the concept of package management, which allows users to easily add, remove,
or upgrade software packages on their systems.</p>
<p>There are many reasons why Slackware is Linux's oldest living distribution. It does
not try to emulate Windows, it tries to be as Unix-like as possible. It does not try to
cover up processes with fancy, point-and-click GUIs (Graphical User Interfaces). Instead,
it puts users in control by letting them see exactly what's going on. Its development is
not rushed to meet deadlines-each version comes out when it is ready.</p>
<p>Slackware is for people who enjoy learning and tweaking their system to do exactly
what they want. Slackware's stability and simplicity are why people will continue to use
it for years to come. Slackware currently enjoys a reputation as a solid server and a
no-nonsense workstation. You can find Slackware desktops running nearly any window
manager or desktop environment, or none at all. Slackware servers power businesses,
acting in every capacity that a server can be used in. Slackware users are among the most
satisfied Linux users. Of course, we'd say that. :^)</p>
</div>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="INTRODUCTION-OPENSOURCE" name="INTRODUCTION-OPENSOURCE">1.3 Open
Source and Free Software</a></h2>
<p>Within the Linux community, there are two major ideological movements at work. The
Free Software movement (which we'll get into in a moment) is working toward the goal of
making all software free of intellectual property restrictions. Followers of this
movement believe these restrictions hamper technical improvement and work against the
good of the community. The Open Source movement is working toward most of the same goals,
but takes a more pragmatic approach to them. Followers of this movement prefer to base
their arguments on the economic and technical merits of making source code freely
available, rather than the moral and ethical principles that drive the Free Software
Movement.</p>
<p>At the other end of the spectrum are groups that wish to maintain tighter controls
over their software.</p>
<p>The Free Software movement is headed by the Free Software Foundation, a fund-raising
organization for the GNU project. Free software is more of an ideology. The oft-used
expression is “free as in speech, not free as in beer”. In essence, free
software is an attempt to guarantee certain rights for both users and developers. These
freedoms include the freedom to run the program for any reason, to study and modify the
source code, to redistribute the source, and to share any modifications you make. In
order to guarantee these freedoms, the GNU General Public License (GPL) was created. The
GPL, in brief, provides that anyone distributing a compiled program which is licensed
under the GPL must also provide source code, and is free to make modifications to the
program as long as those modifications are also made available in source code form. This
guarantees that once a program is “opened” to the community, it cannot be
“closed” except by consent of every author of every piece of code (even the
modifications) within it. Most Linux programs are licensed under the GPL.</p>
<p>It is important to note that the GPL does not say anything about price. As odd as it
may sound, you can charge for free software. The “free” part is in the
liberties you have with the source code, not in the price you pay for the software.
(However, once someone has sold you, or even given you, a compiled program licensed under
the GPL they are obligated to provide its source code as well.)</p>
<p>Another popular license is the BSD license. In contrast to the GPL, the BSD license
gives no requirement for the release of a program's source code. Software released under
the BSD license allows redistribution in source or binary form provided only a few
conditions are met. The author's credentials cannot be used as a sort of advertisement
for the program. It also indemnifies the author from liability for damages that may arise
from the use of the software. Much of the software included in Slackware Linux is BSD
licensed.</p>
<p>At the forefront of the younger Open Source movement, the Open Source Initiative is an
organization that solely exists to gain support for open source software, that is,
software that has the source code available as well as the ready-to-run program. They do
not offer a specific license, but instead they support the various types of open source
licenses available.</p>
<p>The idea behind the OSI is to get more companies behind open source by allowing them
to write their own open source licenses and have those licenses certified by the Open
Source Initiative. Many companies want to release source code, but do not want to use the
GPL. Since they cannot radically change the GPL, they are offered the opportunity to
provide their own license and have it certified by this organization.</p>
<p>While the Free Software Foundation and the Open Source Initiative work to help each
other, they are not the same thing. The Free Software Foundation uses a specific license
and provides software under that license. The Open Source Initiative seeks support for
all open source licenses, including the one from the Free Software Foundation. The
grounds on which each argues for making source code freely available sometimes divides
the two movements, but the fact that two ideologically diverse groups are working toward
the same goal lends credence to the efforts of each.</p>
</div>
</div>
<div class="CHAPTER">
<hr />
<h1><a id="HELP" name="HELP"></a>Chapter 2 Help</h1>
<p>Often there are times when you might need help with a specific command, setting up a
program, or getting a piece of hardware to work. Maybe you simply want to understand a
given command better, or see what other options are available to use with it. Luckily,
there are a variety of ways that you can get the help you're looking for. When you
install Slackware you have the option of installing packages from the “F”
series which includes FAQs and HOWTOs. Programs also come with help about their options,
configuration files, and usage.</p>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="HELP-SYSTEM" name="HELP-SYSTEM">2.1 System Help</a></h2>
<div class="SECT2">
<h3 class="SECT2"><a id="HELP-SYSTEM-MAN" name="HELP-SYSTEM-MAN">2.1.1 <tt
class="COMMAND">man</tt></a></h3>
<p>The <tt class="COMMAND">man</tt> command (short for “manual”) is the
traditional form of online documentation in Unix and Linux operating systems. Comprised
of specially formatted files, the “man pages”, are written for the vast
majority of commands and are distributed with the software itself. Executing <tt
class="COMMAND">man somecommand</tt> will display the man page for (naturally) the
command specified, in our example this would be the imaginary program <tt
class="COMMAND">somecommand</tt>.</p>
<p>As you might imagine, the amount of man pages can quickly add up, becoming overly
confusing and seriously complicated, even for an advanced user. So, for this reason, man
pages are grouped into enumerated sections. This system has been around for a very long
time; enough so that you will often see commands, programs, and even programming library
functions referred to with their man section number.</p>
<p>For example:</p>
<p>You might see a reference to <tt class="COMMAND">man</tt>(1). The numbering tells you
that “<tt class="COMMAND">man</tt>” is documented in section 1 (user
commands); you can specify that you want the section 1 man page for “man”
with the command <tt class="COMMAND">man 1 man</tt>. Specifying the section that man
should look in is useful in the case of multiple items with the same name.</p>
<div class="TABLE"><a id="AEN409" name="AEN409"></a>
<p><b>Table 2-1. Man Page Sections</b></p>
<table border="0" frame="void" width="100%" class="CALSTABLE">
<col width="25%" />
<col width="75%" />
<thead>
<tr>
<th>Section</th>
<th>Contents</th>
</tr>
</thead>
<tbody>
<tr>
<td>Section 1</td>
<td>user commands (intro only)</td>
</tr>
<tr>
<td>Section 2</td>
<td>system calls</td>
</tr>
<tr>
<td>Section 3</td>
<td>C library calls</td>
</tr>
<tr>
<td>Section 4</td>
<td>devices (e.g., <tt class="FILENAME">hd</tt>, <tt class="FILENAME">sd</tt>)</td>
</tr>
<tr>
<td>Section 5</td>
<td>file formats and protocols (e.g., wtmp, <tt class="FILENAME">/etc/passwd</tt>,
nfs)</td>
</tr>
<tr>
<td>Section 6</td>
<td>games (intro only)</td>
</tr>
<tr>
<td>Section 7</td>
<td>conventions, macro packages, etc. (e.g., nroff, ascii)</td>
</tr>
<tr>
<td>Section 8</td>
<td>system administration (intro only)</td>
</tr>
</tbody>
</table>
</div>
<p>In addition to <tt class="COMMAND">man</tt>(1), there are the commands <tt
class="COMMAND">whatis</tt>(1) and <tt class="COMMAND">apropos</tt>(1) available to you,
whose shared purpose is to make it easier to find information in the man system.</p>
<p>The command <tt class="COMMAND">whatis</tt> gives a very brief description of system
commands, somewhat in the style of a pocket command reference.</p>
<p>Example:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">whatis whatis</kbd>
whatis (1) - search the whatis database for complete words
</pre>
</td>
</tr>
</table>
<p>The command <tt class="COMMAND">apropos</tt> is used to search for a man page
containing a given keyword.</p>
<p>Example:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">apropos wav</kbd>
cdda2wav (1) - a sampling utility that dumps CD audio data into wav sound files
netwave_cs (4) - Xircom Creditcard Netwave device driver
oggdec (1) - simple decoder, Ogg Vorbis file to PCM audio file (WAV or RAW)
wavelan (4) - AT&T GIS WaveLAN ISA device driver
wavelan_cs (4) - AT&T GIS WaveLAN PCMCIA device driver
wvlan_cs (4) - Lucent WaveLAN/IEEE 802.11 device driver
</pre>
</td>
</tr>
</table>
<p>If you'd like further information on any of these commands, read their man pages for
the details. ;)</p>
</div>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="HELP-SYSTEM-DOC" name="HELP-SYSTEM-DOC">2.1.2 The <tt
class="FILENAME">/usr/doc</tt> Directory</a></h3>
<p>The source for most packages that we build comes with some sort of documentation:
README files, usage instructions, license files, etc. Any sort of documentation that
comes with the source is included and installed on your system in the <tt
class="FILENAME">/usr/doc</tt> directory. Each program will (usually) install its own
documentation in the order of:</p>
<p><tt class="FILENAME">/usr/doc/<var
class="REPLACEABLE">$program-$version</var></tt></p>
<p>Where <var class="REPLACEABLE">$program</var> is the name of the program you are
wanting to read about, and <var class="REPLACEABLE">$version</var> is (obviously) the
appropriate version of software package installed on your system.</p>
<p>For example, to read the documentation for the command <tt class="COMMAND">man</tt>(1)
you would want to <tt class="COMMAND">cd</tt> to:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">cd /usr/doc/man-<var
class="REPLACEABLE">$version</var></kbd>
</pre>
</td>
</tr>
</table>
<p>If reading the appropriate man page(s) doesn't provide you with enough information, or
address what you're looking for in particular, the <tt class="FILENAME">/usr/doc</tt>
directory should be your next stop.</p>
</div>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="HELP-SYSTEM-HOWTO" name="HELP-SYSTEM-HOWTO">2.1.3 HOWTOs and
mini-HOWTOs</a></h3>
<p>It is in the truest spirit of the Open Source community that brings us to the
HOWTO/mini-HOWTO collection. These files are exactly what they sound like - documents and
guides describing how to do stuff. If you installed the HOWTO collection, the HOWTOs will
be installed to <tt class="FILENAME">/usr/doc/Linux-HOWTOs</tt> and the mini-HOWTOs to
<tt class="FILENAME">/usr/doc/Linux-mini-HOWTOs</tt>.</p>
<p>Also included in the same package series is a collection of FAQs, which is an acronym
which stands for</p>
<div class="INFORMALTABLE"><a id="AEN497" name="AEN497"></a>
<table border="0" frame="void" class="CALSTABLE">
<col />
<tbody>
<tr>
<td><span class="emphasis"><i class="EMPHASIS">F</i></span>requently</td>
</tr>
<tr>
<td><span class="emphasis"><i class="EMPHASIS">A</i></span>sked</td>
</tr>
<tr>
<td><span class="emphasis"><i class="EMPHASIS">Q</i></span>uestions</td>
</tr>
</tbody>
</table>
</div>
<p>These documents are written in a “Question and answer” style for
(surprise) Frequently Asked Questions. The FAQs can often be a very useful place to look
if you're just looking for a “Quick Fix” to something. If you decide to
install the FAQs during setup, you will find them installed to the <tt
class="FILENAME">/usr/doc/Linux-FAQs</tt> directory.</p>
<p>These files are well worth reading whenever you're not quite sure how to proceed with
something. They cover an amazing range of topics, more often than not in a surprisingly
detailed manner. Good stuff!</p>
</div>
</div>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="HELP-ONLINE" name="HELP-ONLINE">2.2 Online Help</a></h2>
<p>In addition to the documentation provided and installable with the Slackware Linux
Operating System, there are a vast multitude of online resources available for you to
learn from as well.</p>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="HELP-ONLINE-OFFICIAL" name="HELP-ONLINE-OFFICIAL">2.2.1 The
Official Website and Help Forums</a></h3>
<p><a href="http://www.slackware.com" target="_top">The Official Slackware
Website</a></p>
<p>The Official Slackware Linux website is sometimes out of date, but still contains
information relevant to the latest Slackware versions. At one time an active help forum
existed there before a horde of trolls, troublemakers, and whiners descended on the
forum. Maintaining the forum was beginning to be too much work, and so Pat shut it down.
One can find that old forum back up and running complete with searchable archives of the
old data at <a href="http://www.userlocal.com/phorum/"
target="_top">http://www.userlocal.com/phorum/</a>.</p>
<p>After the forums were taken down on <a href="http://slackware.com"
target="_top">http://slackware.com</a>, several other sites sprang up that offered forum
support for Slackware. After much thought, Pat chose to endorse <a
href="www.linuxquestions.org" target="_top">www.linuxquestions.org</a> as the official
forum for Slackware Linux.</p>
</div>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="HELP-ONLINE-EMAIL" name="HELP-ONLINE-EMAIL">2.2.2 E-mail
Support</a></h3>
<p>Everyone who purchases an official CD set is entitled to free installation support via
e-mail from the developer. That having been said, please keep in mind that we, the
developers, (and a vast majority of users) of Slackware are of “The Old
School”. That means that we prefer to help those who have a sincere interest and
are willing to help themselves in the process. We will always do our best to help
everyone who emails us with support questions. However, Please check your documentation
and the website (especially the FAQs and maybe some of the forums listed below) before
e-mailing. You may get a faster answer that way, and the less e-mail we have to answer,
obviously the sooner we will be of assistance to those that need it.</p>
<p>The e-mail address for technical support is: <var
class="LITERAL">support@slackware.com</var>. Other e-mail addresses and contact
information are listed on the website.</p>
<div class="SECT3">
<hr />
<h4 class="SECT3"><a id="AEN535" name="AEN535">2.2.2.1 Slackware Linux Project Mailing
Lists</a></h4>
<p>We have several mailing lists, available in digest and normal forms. Check the
instructions for how to subscribe.</p>
<p>To subscribe to a mailing list, email:</p>
<p><var class="LITERAL">majordomo@slackware.com</var></p>
<p>with the phrase “<var class="LITERAL">subscribe <var class="REPLACEABLE">[name
of list]</var></var>” in the body of the email. The list choices are described
below (use one the names below for the name of the list).</p>
<p>Archives of the mailing list can be found on Slackware's website at:</p>
<p><var class="LITERAL">http://slackware.com/lists/archive/</var></p>
<div class="VARIABLELIST">
<dl>
<dt><var class="LITERAL">slackware-announce</var></dt>
<dd>
<p>The <var class="LITERAL">slackware-announce</var> mailing list is for announcements of
new versions, major updates and other general information.</p>
</dd>
<dt><var class="LITERAL">slackware-security</var></dt>
<dd>
<p>The <var class="LITERAL">slackware-security</var> mailing list is for announcements
relating to security issues. Any exploits or other vulnerabilities directly pertaining to
Slackware will get posted to this list immediately.</p>
</dd>
</dl>
</div>
<p>These lists are also available in digest format. This means that you get one large
message per day instead of several messages throughout the day. Since the slackware
mailing lists do not allow users to post, and the lists are such low traffic, most users
find little advantage in the digest lists. Still, they are available if you want them by
subscribing to <var class="LITERAL">slackware-announce-digest</var> or <var
class="LITERAL">slackware-security-digest</var>.</p>
</div>
</div>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="HELP-ONLINE-NONOFFICIAL" name="HELP-ONLINE-NONOFFICIAL">2.2.3
Non-Official Websites and Help Forums</a></h3>
<div class="SECT3">
<h4 class="SECT3"><a id="AEN571" name="AEN571">2.2.3.1 Websites</a></h4>
<div class="VARIABLELIST">
<dl>
<dt><a href="http://www.google.com" target="_top">Google</a></dt>
<dd>
<p>The Kung-Fu Master of Search Engines. When you absolutely, positively gotta find every
last kernel of information on a subject: Accept no substitutes.</p>
</dd>
<dt><a href="http://www.google.com/linux" target="_top">Google:Linux</a></dt>
<dd>
<p>Linux-Specific searches</p>
</dd>
<dt><a href="http://www.google.com/bsd" target="_top">Google:BSD</a></dt>
<dd>
<p>BSD-Specific searches. Slackware is so generic as a Unix work-a-like operating system
that one can as often as not find very detailed information that is almost 100% relevant
to Slackware here. Many times a BSD search reveals far more technical information than
the often PR-related Linux searches.</p>
</dd>
<dt><a href="http://groups.google.com" target="_top">Google:Groups</a></dt>
<dd>
<p>Search through decades of Usenet posts for your pearls of wisdom.</p>
</dd>
<dt><a href="http://userlocal.com" target="_top">http://userlocal.com</a></dt>
<dd>
<p>A virtual treasure-trove of knowledge, good advice, first-hand experience and
interesting articles. Often the first place you'll hear about new developments in the
world of Slackware.</p>
</dd>
</dl>
</div>
</div>
<div class="SECT3">
<hr />
<h4 class="SECT3"><a id="AEN601" name="AEN601">2.2.3.2 Web-based Resources</a></h4>
<div class="VARIABLELIST">
<dl>
<dt><a href="http://www.linuxquestions.org/questions/forumdisplay.php?forumid=14"
target="_top">linuxquestions.org</a></dt>
<dd>
<p>The officially sanctioned web-forum for Slackware users.</p>
</dd>
<dt><a href="http://forums.linuxiso.org/viewforum.php?f=25" target="_top">LinuxISO.org
Slackware Forum</a></dt>
<dd>
<p>“A place to download and get help with Linux.”</p>
</dd>
<dt><a href="http://wombat.san-francisco.ca.us/perl/fom"
target="_top">alt.os.linux.slackware FAQ</a></dt>
<dd>
<p>Another FAQ</p>
</dd>
</dl>
</div>
</div>
<div class="SECT3">
<hr />
<h4 class="SECT3"><a id="AEN620" name="AEN620">2.2.3.3 Usenet Groups (NNTP)</a></h4>
<p>Usenet has long been a place for geeks to gather and help one another. There are few
newsgroups dedicated to Slackware Linux, but they tend to be filled with very
knowledgeable people.</p>
<p><var class="LITERAL">alt.os.linux.slackware</var></p>
<p><var class="LITERAL">alt.os.linux.slackware</var>, better known as aols (not to be
confused with <span class="TRADEMARK">AOL</span>®!) is one of the most active places
to find technical help with Slackware problems. Like every Usenet newsgroup, a few
unhelpful participants (“trolls”) can mar the experience with constant
arguing. Learning to ignore the trolls and identifying the truly helpful people is key to
making the most of this resource.</p>
</div>
</div>
</div>
</div>
<div class="CHAPTER">
<hr />
<h1><a id="INSTALLATION" name="INSTALLATION"></a>Chapter 3 Installation</h1>
<p>Before you can use Slackware Linux, you'll have to obtain and install it. Getting
Slackware is as easy as purchasing it or downloading it for free over the Internet.
Installing it is also easy as long as you have some basic knowledge about your computer
and are willing to learn a few other things. The installation program itself is very much
a step-by-step process. Because of this, you can be up and running very quickly. In fact,
Slackware boasts one of the lowest installation times of any full-featured Linux
distribution.</p>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="INSTALLATION-GETTING" name="INSTALLATION-GETTING">3.1 Getting
Slackware</a></h2>
<div class="SECT2">
<h3 class="SECT2"><a id="AEN641" name="AEN641">3.1.1 The Official Disc and Box
Sets</a></h3>
<p>The official Slackware Linux CD set is available from Slackware Linux, Inc. The CD set
consists of 4 discs. The first disk contains all the software needed for a basic server
install, and the X window system. The second cd is a “live” cd; that is, a
bootable cd that installs into RAM and gives you a temporary installation to play around
with or do a data or machine rescue. This cd also contains a few packages such as the KDE
and GNOME desktop environments. A few other goodies are included on the second cd
including many non-vital packages in the “extra” folder. The third and fourth
CDs contain the source code to all of Slackware, along with the original edition of this
book.</p>
<p>One may also purchase a boxed set that includes the 4 discs and a copy of this book,
as well as lots of neat Slackware gear to show off your geek pride. CD subscriptions are
available at a reduced rate also.</p>
<p>The preferred method for shopping for Slackware merchandise is online at the Slackware
store.</p>
<p><a href="http://store.slackware.com" target="_top">http://store.slackware.com</a></p>
<p>You can also call or e-mail your order in.</p>
<div class="TABLE"><a id="AEN661" name="AEN661"></a>
<p><b>Table 3-1. Slackware Linux, Inc. Contact Information</b></p>
<table border="0" frame="void" class="CALSTABLE">
<col width="1*" />
<col width="2*" />
<thead>
<tr>
<th>Method</th>
<th>Contact Details</th>
</tr>
</thead>
<tbody>
<tr>
<td>Telephone</td>
<td>1-(925) 674-0783</td>
</tr>
<tr>
<td>Website</td>
<td>http://store.slackware.com</td>
</tr>
<tr>
<td>Email</td>
<td>orders@slackware.com</td>
</tr>
<tr>
<td>Postal</td>
<td>1164 Claremont Drive, Brentwood, CA 94513</td>
</tr>
</tbody>
</table>
</div>
</div>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="AEN683" name="AEN683">3.1.2 Via the Internet</a></h3>
<p>Slackware Linux is also freely available over the Internet. You may email in your
support questions, but higher priority will be given to those who have purchased the
official CD set. With that said, we get a lot of e-mails and our time is rather limited.
Before e-mailing for support consider reading <a href="#HELP">Chapter 2</a> first.</p>
<p>The official Slackware Linux Project website is located at:</p>
<p><a href="http://www.slackware.com/" target="_top">http://www.slackware.com/</a></p>
<p>The primary FTP location for Slackware Linux is:</p>
<p><a href="ftp://ftp.slackware.com/pub/slackware/"
target="_top">ftp://ftp.slackware.com/pub/slackware/</a></p>
<p>Bear in mind that our ftp site, while open for general use, does not have unlimited
bandwidth. Please consider using a mirror near you to download Slackware. An incomplete
list of mirrors can be found on our site at <a href="http://www.slackware.com/getslack"
target="_top">http://www.slackware.com/getslack</a>.</p>
</div>
</div>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="INSTALLATION-REQUIREMENTS" name="INSTALLATION-REQUIREMENTS">3.2
System Requirements</a></h2>
<p>An easy Slackware installation requires, at minimum, the following:</p>
<div class="TABLE"><a id="AEN706" name="AEN706"></a>
<p><b>Table 3-2. System Requirements</b></p>
<table border="0" frame="void" class="CALSTABLE">
<col />
<col />
<thead>
<tr>
<th>Hardware</th>
<th>Requirement</th>
</tr>
</thead>
<tbody>
<tr>
<td>Processor</td>
<td>586</td>
</tr>
<tr>
<td>RAM</td>
<td>32 MB</td>
</tr>
<tr>
<td>Disk Space</td>
<td>1GB</td>
</tr>
<tr>
<td>Media Drive</td>
<td>4x CD-ROM</td>
</tr>
</tbody>
</table>
</div>
<p>If you have the bootable CD, you will probably not need a floppy drive. Of course, it
stands to reason that if you don't possess a CD-ROM drive, you will need a floppy drive
to do a network install. A network card is required for an NFS install. See the section
called NFS for more information.</p>
<p>The disk space requirement is somewhat tricky. The 1GB recommendation is usually safe
for a minimal install, but if you do a full install, you will need around two gigabytes
of available hard disk space plus additional space for personal files.. Most users don't
do a full install. In fact, many run Slackware on as little as 100MB of hard disk
space.</p>
<p>Slackware can be installed to systems with less RAM, smaller hard drives, and weaker
CPUs, but doing so will require a little elbow grease. If you're up for a little work,
take a look at the <tt class="FILENAME">LOWMEM.TXT</tt> file in the distribution tree for
a few helpful hints.</p>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="INSTALLATION-SOFTWARE-SERIES"
name="INSTALLATION-SOFTWARE-SERIES">3.2.1 The Software Series</a></h3>
<p>For reasons of simplicity, Slackware has historically been divided into software
series. Once called “disk sets” because they were designed for floppy-based
installation, the software series are now used primarily to categorize the packages
included in Slackware. Today, floppy installation is no longer possible.</p>
<p>The following is a brief description of each software series.</p>
<div class="TABLE"><a id="AEN746" name="AEN746"></a>
<p><b>Table 3-3. Software Series</b></p>
<table border="0" frame="void" class="CALSTABLE">
<col width="1*" />
<col width="4*" />
<thead>
<tr>
<th>Series</th>
<th>Contents</th>
</tr>
</thead>
<tbody>
<tr>
<td>A</td>
<td>The base system. Contains enough software to get up and running and have a text
editor and basic communication program.</td>
</tr>
<tr>
<td>AP</td>
<td>Various applications that do not require the X Window System.</td>
</tr>
<tr>
<td>D</td>
<td>Program development tools. Compilers, debuggers, interpreters, and man pages are all
here.</td>
</tr>
<tr>
<td>E</td>
<td>GNU Emacs.</td>
</tr>
<tr>
<td>F</td>
<td>FAQs, HOWTOs, and other miscellaneous documentation.</td>
</tr>
<tr>
<td>GNOME</td>
<td>The GNOME desktop environment.</td>
</tr>
<tr>
<td>K</td>
<td>The source code for the Linux kernel.</td>
</tr>
<tr>
<td>KDE</td>
<td>The K Desktop Environment. An X environment which shares a lot of look-and-feel
features with MacOS and Windows. The Qt library, which KDE requires, is also in this
series.</td>
</tr>
<tr>
<td>KDEI</td>
<td>Internationalization packages for the KDE desktop.</td>
</tr>
<tr>
<td>L</td>
<td>Libraries. Dynamically linked libraries required by many other programs.</td>
</tr>
<tr>
<td>N</td>
<td>Networking programs. Daemons, mail programs, telnet, news readers, and so on.</td>
</tr>
<tr>
<td>T</td>
<td>teTeX document formatting system.</td>
</tr>
<tr>
<td>TCL</td>
<td>The Tool Command Language. Tk, TclX, and TkDesk.</td>
</tr>
<tr>
<td>X</td>
<td>The base X Window System.</td>
</tr>
<tr>
<td>XAP</td>
<td>X Applications that are not part of a major desktop environment (for example,
Ghostscript and Netscape).</td>
</tr>
<tr>
<td>Y</td>
<td>BSD Console games</td>
</tr>
</tbody>
</table>
</div>
</div>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="INSTALLATION-METHODS" name="INSTALLATION-METHODS">3.2.2
Installation Methods</a></h3>
<div class="SECT3">
<h4 class="SECT3"><a id="INSTALLATION-INSTALLATION-METHODS-FLOPPY"
name="INSTALLATION-INSTALLATION-METHODS-FLOPPY">3.2.2.1 Floppy</a></h4>
<p>While it was once possible to install all of Slackware Linux from floppy disks, the
increasing size of software packages (indeed, of some individual programs) has forced the
abandonment of the floppy install. As late as Slackware version 7.1 a partial install was
possible using floppy disks. The A and N series could be nearly entirely installed,
providing a base system from which to install the rest of the distribution. If you are
considering a floppy install (typically on older hardware), it is typically recommended
to find another way, or use an older release. Slackware 4.0 is still very popular for
this reason, as is 7.0.</p>
<p>Please note that floppy disks are still required for a CD-ROM install if you do not
have a bootable CD, as well as for an NFS install.</p>
</div>
<div class="SECT3">
<hr />
<h4 class="SECT3"><a id="INSTALLATION-INSTALLLATION-METHODS-CDROM"
name="INSTALLATION-INSTALLLATION-METHODS-CDROM">3.2.2.2 CD-ROM</a></h4>
<p>If you have the bootable CD, available in the official disc set published by Slackware
Linux, Inc. (see the section called Getting Slackware), a CD-based installation will be a
bit simpler for you. If not, you will need to boot from floppies. Also, if you have
special hardware that makes usage of the kernel on the bootable CD problematic, you may
need to use specialized floppies.</p>
<p>As of Slackware version 8.1, a new method is used for creating the bootable CDs, which
does not work as well with certain flaky BIOS chips (it is worth noting that most all
Linux CDs suffer from this these days). If that is the case, we recommend booting from a
floppy disk.</p>
<p><a href="#INSTALLATION-INSTALLATION-METHODS-BOOTDISK">Section 3.2.3</a> and <a
href="#INSTALLATION-SUPPLEMENTAL-DISK">Section 3.2.5</a> provide information on choosing
and creating floppies from which to boot, should this be necessary.</p>
</div>
<div class="SECT3">
<hr />
<h4 class="SECT3"><a id="AEN823" name="AEN823">3.2.2.3 NFS</a></h4>
<p>NFS (the Network File System) is a way of making filesystems available to remote
machines. An NFS install allows you to install Slackware from another computer on your
network. The machine from which you are installing needs to be configured to export the
Slackware distribution tree to the machine to which you're installing. This, of course,
involves some knowledge of NFS, which is covered in <a
href="#NETWORK-CONFIGURATION-NFS">Section 5.6</a>.</p>
<p>It is possible to perform an NFS install via such methods as PLIP (over a parallel
port), SLIP, and PPP (though not over a modem connection). However, we recommend the use
of a network card if available. After all, installing an operating system through your
printer port is going to be a very, very slow process.</p>
</div>
</div>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="INSTALLATION-INSTALLATION-METHODS-BOOTDISK"
name="INSTALLATION-INSTALLATION-METHODS-BOOTDISK">3.2.3 Boot Disk</a></h3>
<p>The boot disk is the floppy you actually boot from to begin the installation. It
contains a compressed kernel image which is used to control the hardware during
installation. Therefore, it is very much required (unless you're booting from CD, as is
discussed in the section called CD-ROM). The boot disks are located in the <tt
class="FILENAME">bootdisks/</tt> directory in the distribution tree.</p>
<p>There are more Slackware boot disks than you can shake a stick at (which is to say
about 16). A complete list of boot disks, with a description of each, is available in the
Slackware distribution tree in the file <tt class="FILENAME">bootdisks/README.TXT</tt>.
However, most people are able to use the <tt class="FILENAME">bare.i</tt> (for IDE
devices) or <tt class="FILENAME">scsi.s</tt> (for SCSI devices) boot disk image.</p>
<p>See <a href="#INSTALLATION-MAKING-THE-DISKS">Section 3.2.6</a> for instructions on
making a disk from an image.</p>
<p>After booting, you will be prompted to insert the root disk. We recommend that you
just humor the boot disk and play along.</p>
</div>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="INSTALLATION-INSTALLATION-METHODS-ROOTDISK"
name="INSTALLATION-INSTALLATION-METHODS-ROOTDISK">3.2.4 Root Disk</a></h3>
<p>The root disks contain the setup program and a filesystem which is used during
installation. They are also required. The root disk images are located in the directory
rootdisks in the distribution tree. You'll have to make two root disks from the <tt
class="FILENAME">install.1</tt> and <tt class="FILENAME">install.2</tt> images. Here you
can also find the <tt class="FILENAME">network.dsk</tt>, <tt
class="FILENAME">pcmcia.dsk</tt>, <tt class="FILENAME">rescue.dsk</tt>, and <tt
class="FILENAME">sbootmgr.dsk</tt> disks.</p>
</div>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="INSTALLATION-SUPPLEMENTAL-DISK"
name="INSTALLATION-SUPPLEMENTAL-DISK">3.2.5 Supplemental Disk</a></h3>
<p>A supplemental disk is needed if you are performing an NFS install or installing to a
system with PCMCIA devices. Supplemental disks are in the rootdsks directory in the
distribution tree, with the filenames <tt class="FILENAME">network.dsk</tt> and <tt
class="FILENAME">pcmcia.dsk</tt>. Recently other supplemental disks such as <tt
class="FILENAME">rescue.dsk</tt> and <tt class="FILENAME">sbootmgr.dsk</tt> have been
added. The rescue disk is a small floppy root image that runs in a 4MB RAM drive. It
includes some basic networking utilities and the vi editor for quick fixes on busted
machines. The <tt class="FILENAME">sbootmgr.dsk</tt> disk is used to boot other devices.
Boot off this disk if your bootable CD-ROM drive doesn't want to boot the Slackware CDs.
It will prompt you for different things to boot and may offer a convenient way to work
around a buggy BIOS.</p>
<p>The root disk will instruct you on the use of supplemental disks when it is
loaded.</p>
</div>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="INSTALLATION-MAKING-THE-DISKS"
name="INSTALLATION-MAKING-THE-DISKS">3.2.6 Making the Disks</a></h3>
<p>Once you've selected a boot disk image, you need to put it on a floppy. The process is
slightly different depending on which operating system you're using to make the disks. If
you're running Linux (or pretty much any Unix-like OS) you'll need to use the <tt
class="COMMAND">dd</tt>(1) command. Assuming <tt class="FILENAME">bare.i</tt> is your
disk image file and your floppy drive is <tt class="FILENAME">/dev/fd0</tt>, the command
to make a <tt class="FILENAME">bare.i</tt> floppy is:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">dd if=bare.i of=/dev/fd0</kbd>
</pre>
</td>
</tr>
</table>
<p>If you're running a Microsoft OS, you'll need to use the <tt
class="FILENAME">RAWRITE.EXE</tt> program, which is included in the distribution tree in
the same directories as the floppy images. Again assuming that <tt
class="FILENAME">bare.i</tt> is your disk image file and your floppy drive is <tt
class="FILENAME">A:</tt>, open a DOS prompt and type the following:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
C:\ <kbd class="USERINPUT">rawrite a: bare.i</kbd>
</pre>
</td>
</tr>
</table>
</div>
</div>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="INSTALLATION-PARTITIONING" name="INSTALLATION-PARTITIONING">3.3
Partitioning</a></h2>
<p>After booting from your preferred media, you will need to partition your hard disk.
The disk partition is where the Linux filesystem will be created and is where Slackware
will be installed. At the very minimum we recommend creating two partitions; one for your
root filesystem (<tt class="FILENAME">/</tt>) and one for swap space.</p>
<p>After the root disk finishes loading, it will present you with a login prompt. Log in
as root (there is no password). At the shell prompt, run either <tt
class="COMMAND">cfdisk</tt>(8) or <tt class="COMMAND">fdisk</tt>(8). The <tt
class="COMMAND">cfdisk</tt> program provides a more user-friendly interface than the
regular <tt class="COMMAND">fdisk</tt> program, but does lack some features. We will
briefly explain the <tt class="COMMAND">fdisk</tt> program below.</p>
<p>Begin by running <tt class="COMMAND">fdisk</tt> for your hard disk. In Linux, the hard
disks do not have drive letters, but are represented by a file. The first IDE hard disk
(primary master) is <tt class="FILENAME">/dev/hda</tt>, the primary slave is <tt
class="FILENAME">/dev/hdb</tt>, and so on. SCSI disks follow the same type system, but
are in the form of <tt class="FILENAME">/dev/sd<var class="REPLACEABLE">X</var></tt>. You
will need to start <tt class="COMMAND">fdisk</tt> and pass it your hard disk:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">#</samp> <kbd class="USERINPUT">fdisk /dev/hda</kbd>
</pre>
</td>
</tr>
</table>
<p>Like all good Unix programs, <tt class="COMMAND">fdisk</tt> gives you a prompt
(thought you were getting a menu, right?). The first thing you should do is examine your
current partitions. We do that by typing <kbd class="USERINPUT">p</kbd> at the <tt
class="COMMAND">fdisk</tt> prompt:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
Command (m for help): <kbd class="USERINPUT">p</kbd>
</pre>
</td>
</tr>
</table>
<p>This will display all sorts of information about your current partitions. Most people
pick a free drive to install to and then remove any existing partitions on it to create
room for the Linux partitions.</p>
<div class="WARNING">
<table class="WARNING" width="100%" border="0">
<tr>
<td width="25" align="CENTER" valign="TOP"><img src="./imagelib/admon/warning.png"
hspace="5" alt="Warning" /></td>
<td align="LEFT" valign="TOP">
<p>IT IS VERY IMPORTANT THAT YOU BACK UP ANY INFORMATION YOU WANT TO SAVE BEFORE
DESTROYING THE PARTITION IT LIVES ON.</p>
</td>
</tr>
</table>
</div>
<p>There is no easy way to recover from deleting a partition, so always back up before
playing with them.</p>
<p>Looking at the table of partition information you should see a partition number, the
size of the partition, and its type. There's more information, but don't worry about that
for now. We are going to delete all of the partitions on this drive to create the Linux
ones. We run the <kbd class="USERINPUT">d</kbd> command to delete those:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
Command (m for help): <kbd class="USERINPUT">d</kbd>
Partition number (1-4): <kbd class="USERINPUT">1</kbd>
</pre>
</td>
</tr>
</table>
<p>This process should be continued for each of the partitions. After deleting the
partitions we are ready to create the Linux ones. We have decided to create one partition
for our root filesystem and one for swap. It is worth noting that Unix partitioning
schemes are the subject of many flame wars, and that most users will tell you the best
way to do it. At a minimum, you should create one partition for <tt
class="FILENAME">/</tt> and one for swap. Over time, you'll develop a method that works
well for you.</p>
<p>I use two basic partition schemes. The first is for a desktop. I make 4 partitions,
<tt class="FILENAME">/</tt>, <tt class="FILENAME">/home</tt>, <tt
class="FILENAME">/usr/local</tt>, and swap. This lets me re-install or upgrade the entire
installation under <tt class="FILENAME">/</tt> without wiping out my data files under
/home or my custom compiled applications under <tt class="FILENAME">/usr/local</tt>. For
servers, I often replace the <tt class="FILENAME">/usr/local</tt> partition with a <tt
class="FILENAME">/var</tt> partition. Many different servers store information on that
partition and having it kept separate from <tt class="FILENAME">/</tt> has certain
performance benefits. For now, we're sticking with just two partitions: <tt
class="FILENAME">/</tt> and swap.</p>
<p>Now we create the partitions with the <kbd class="USERINPUT">n</kbd> command:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
Command (m for help): <kbd class="USERINPUT">n</kbd>
Command action
e extended
p primary partition (1-4)
<kbd class="USERINPUT">p</kbd>
Partition number (1-4):<kbd class="USERINPUT">1</kbd>
First cylinder (0-1060, default 0):<kbd class="USERINPUT">0</kbd>
Last cylinder or +size or +sizeM or +sizeK (0-1060, default 1060):<kbd
class="USERINPUT">+64M</kbd>
</pre>
</td>
</tr>
</table>
<p>You need to make sure you create primary partitions. The first partition is going to
be our swap partition. We tell fdisk to make partition number 1 a primary partition. We
start it at cylinder 0 and for the ending cylinder we type +64M. This will give us a 64
megabyte partition for swap. (The size of the swap partition you need actually depends on
the amount of RAM you have. It is conventional wisdom that a swap space double the size
of your RAM should be created.) Then we define primary partition number 2 starting at the
first available cylinder and going all the way to the end of the drive.</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
Command (m for help):<kbd class="USERINPUT">n</kbd>
Command action
e extended
p primary partition (1-4)
<kbd class="USERINPUT">p</kbd>
Partition number (1-4):<kbd class="USERINPUT">2</kbd>
First cylinder (124-1060, default 124):<kbd class="USERINPUT">124</kbd>
Last cylinder or +size or +sizeM or +sizeK (124-1060, default 1060):<kbd
class="USERINPUT">1060</kbd>
</pre>
</td>
</tr>
</table>
<p>We are almost done. We need to change the type of the first partition to type 82
(Linux swap). Type <kbd class="USERINPUT">t</kbd> to change the type, select the first
partition, and type <var class="LITERAL">82</var>. Before writing your changes to the
disk, you should look at the new partition table one last time. Use the <kbd
class="USERINPUT">p</kbd> in <tt class="COMMAND">fdisk</tt> to display the partition
table. If everything looks good, type <kbd class="USERINPUT">w</kbd> to write your
changes to the disk and quit <tt class="COMMAND">fdisk</tt>.</p>
</div>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="INSTALLATION-SETUP" name="INSTALLATION-SETUP">3.4 The <tt
class="COMMAND">setup</tt> Program</a></h2>
<p>Once you have created your partitions, you are ready to install Slackware. The next
step in the installation process is running the <tt class="COMMAND">setup</tt>(8)
program. To do so, simply type <tt class="COMMAND">setup</tt> at the shell prompt. <tt
class="COMMAND">setup</tt> is a menu-driven system for actually installing the Slackware
packages and configuring your system.</p>
<div class="INFORMALFIGURE"><a id="AEN981" name="AEN981"></a>
<p><img src="installation/setup-program-w.png" /></p>
</div>
<p>The setup process goes something like this: You step through each option in the <tt
class="COMMAND">setup</tt> program, in the order they are listed. (Of course, you are
free to do things in almost any order you choose, but chances are it isn't going to work
out very well.) Menu items are selected using the up and down arrow keys, and the
“Okay” and “Cancel” buttons can be chosen by using the left and
right arrow keys. Alternatively, each option has a corresponding key, which is
highlighted in the option name. Options which are flaggable (those indicated with a <var
class="LITERAL">[X]</var>) are toggled using the spacebar.</p>
<p>Of course, all of that is described in the “help” section of <tt
class="COMMAND">setup</tt>, but we believe in giving our readers their money's worth.</p>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="AEN993" name="AEN993">3.4.1 HELP</a></h3>
<p>If this is your first time installing Slackware, you might want to take a look at the
help screen. It will give a description of each part of <tt class="COMMAND">setup</tt>
(much like the one we're writing now, but less involved) and instructions for navigating
the rest of the install.</p>
<div class="INFORMALFIGURE"><a id="AEN997" name="AEN997"></a>
<p><img src="installation/setup-help-w.png" /></p>
</div>
</div>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="AEN1001" name="AEN1001">3.4.2 KEYMAP</a></h3>
<p>If you require a keymap other than the United States “qwerty” layout, you
may want to take a look at this section. It offers a number of alternate layouts for your
keyboarding enjoyment.</p>
<div class="INFORMALFIGURE"><a id="AEN1009" name="AEN1009"></a>
<p><img src="installation/setup-keymap-w.png" /></p>
</div>
</div>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="AEN1013" name="AEN1013">3.4.3 ADDSWAP</a></h3>
<div class="INFORMALFIGURE"><a id="AEN1015" name="AEN1015"></a>
<p><img src="installation/setup-swap-w.png" /></p>
</div>
<p>If you created a swap partition (back in <a href="#INSTALLATION-PARTITIONING">Section
3.3</a>), this section will allow you to enable it. It will autodetect and display the
swap partitions on your hard drive, allowing you to select one to format and enable.</p>
</div>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="AEN1023" name="AEN1023">3.4.4 TARGET</a></h3>
<div class="INFORMALFIGURE"><a id="AEN1025" name="AEN1025"></a>
<p><img src="installation/setup-target-w.png" /></p>
</div>
<p>The target section is where your other (non-swap) partitions are formatted and mapped
to filesystem mount points. A list of the partitions on your hard disk will be displayed.
For each partition, you will be given the option of whether to format that partition or
not. Depending on the kernel used, you can choose between reiserfs (the default), ext3,
ext2, jfs, and xfs. Most people use either reiserfs or ext3. In the near future we may
see support for reiserfs4 slip in.</p>
<p>The first option in the target section is the selection of a partition on which to
install your root (<tt class="FILENAME">/</tt>) filesystem. After that, you will be able
to map other partitions to filesystems as you choose. (For instance, you may want your
third partition, say <tt class="FILENAME">/dev/hda3</tt>, to be your home filesystem.
This is just an example; map the partitions as you see fit.)</p>
</div>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="AEN1035" name="AEN1035">3.4.5 SOURCE</a></h3>
<p>The source section is where you select the source media from which you are installing
Slackware. Currently there are four sources to choose from. These are CD-ROM, NFS, or a
premounted directory.</p>
<div class="INFORMALFIGURE"><a id="AEN1038" name="AEN1038"></a>
<p><img src="installation/setup-source-w.png" /></p>
</div>
<p>The CD-ROM selection enables a CD-ROM based installation. It will offer the option of
scanning for a CD-ROM drive or displaying a list from which you can pick your drive type.
Make sure you have the Slackware CD in your drive before allowing it to scan.</p>
<p>The NFS selection prompts for your network information and the network information for
your NFS server. The NFS server must be set up in advance. Also note that you cannot use
hostnames, you must use the IP addresses for both your machine and the NFS server (there
is no name resolver on the setup disk). Naturally you must have used the <tt
class="FILENAME">network.dsk</tt> floppy to add support for your network controller.</p>
<p>The premounted directory offers the most flexibility. You can use this method to
install from things such as Jaz disks, NFS mounts over PLIP, and FAT filesystems. Mount
the filesystem to a location of your choosing before running setup, then specify that
location here.</p>
</div>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="AEN1054" name="AEN1054">3.4.6 SELECT</a></h3>
<p>The select option allows you to select the software series that you wish to install.
These series are described in <a href="#INSTALLATION-SOFTWARE-SERIES">Section 3.2.1</a>.
Please note that you must install the A series to have a working base system. All other
series are optional.</p>
<div class="INFORMALFIGURE"><a id="AEN1058" name="AEN1058"></a>
<p><img src="installation/setup-select-w.png" /></p>
</div>
</div>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="AEN1062" name="AEN1062">3.4.7 INSTALL</a></h3>
<p>Assuming that you have gone through the “target”, “source”,
and “select” options, the <var class="OPTION">install</var> option will allow
you to select packages from your chosen software series. If not, it will prompt you to go
back and complete the other sections of the setup program. This option allows you to
select from six different installation methods: <var class="OPTION">full</var>, <var
class="OPTION">newbie</var>, <var class="OPTION">menu</var>, <var
class="OPTION">expert</var>, <var class="OPTION">custom</var>, and <var
class="OPTION">tag path</var>.</p>
<div class="INFORMALFIGURE"><a id="AEN1077" name="AEN1077"></a>
<p><img src="installation/setup-install-w.png" /></p>
</div>
<p>The <var class="OPTION">full</var> option will install every package from all the
software series that you chose in the “select” section. There is no further
prompting. This is the easiest installation method, since you do not need to make any
decisions on the actual packages to install. Of course, this option also takes up the
most hard drive space.</p>
<p>The next option is <var class="OPTION">newbie</var>. This option installs all of the
required packages in the selected series. For all other packages, it offers a prompt
where you can select “Yes”, “No”, or “Skip”. Yes and
No do the obvious, while Skip will go ahead to the next software series. Additionally,
you will see a description and size requirement for each package to help you decide if
you need it. We recommend this option for new users, as it ensures that you get all the
required packages installed. However, it is a little slow because of the prompting.</p>
<p><var class="OPTION">Menu</var> is a faster and more advanced version of the newbie
option. For each series, a menu is displayed, from which you can select all the
non-required packages you want to install. Required packages are not displayed on this
menu.</p>
<p>For the more advanced user, install offers the <var class="OPTION">expert</var>
option. This allows you complete control over what packages get installed. You can
deselect packages that are absolutely required, resulting in a broken system. On the
other hand, you can control exactly what goes onto your system. Simply select the
packages from each series that you want installed. This is not recommended for the new
user, as it is quite easy to shoot yourself in the foot.</p>
<p>The <var class="OPTION">custom</var> and <var class="OPTION">tag path</var> options
are also for advanced users. These options allow you to install based upon custom tag
files that you created in the distribution tree. This is useful for installing to large
numbers of machines fairly quickly. For more information on using tag files, see <a
href="#PACKAGE-MANAGEMENT-MAKING-TAGS-AND-TAGFILES">Section 18.4</a>.</p>
<p>After selecting your installation method, one of a few things will happen. If you
selected full or menu, a menu screen will appear, allowing you to select the packages to
be installed. If you selected full, packages will immediately start getting installed to
the target. If you selected newbie, packages will be installed until an optional package
is reached.</p>
<p>Note that it is possible to run out of space while installing. If you selected too
many packages for the amount of free space on the target device, you will have problems.
The safest thing to do is to select some software and add more later, if you need it.
This can easily be done using Slackware's package management tools. For this information,
see <a href="#PACKAGE-MANAGEMENT">Chapter 18</a>.</p>
</div>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="AEN1100" name="AEN1100">3.4.8 CONFIGURE</a></h3>
<p>The configure section allows you to do some basic system configuration, now that the
packages have been installed. What you see here depends in large part upon which software
you have installed. You will, however, always see the following:</p>
<div class="SECT3">
<hr />
<h4 class="SECT3"><a id="AEN1103" name="AEN1103">3.4.8.1 Kernel selection</a></h4>
<p>Here you will be asked to select a kernel to install. You can install the kernel from
the boot disk you used to install, the Slackware CD-ROM, or from another floppy which you
(always thinking ahead) have prepared. Or you can elect to skip, in which case the
default kernel will be installed and play will continue to the dealer's left.</p>
<div class="INFORMALFIGURE"><a id="AEN1106" name="AEN1106"></a>
<p><img src="installation/setup-kernel-w.png" /></p>
</div>
</div>
<div class="SECT3">
<hr />
<h4 class="SECT3"><a id="AEN1110" name="AEN1110">3.4.8.2 Make a boot disk</a></h4>
<p>Making a boot disk for future use is probably a good idea. You will have the option of
formatting a floppy and then creating one of two types of boot disk. The first type, <var
class="OPTION">simple</var>, simply (go figure) writes a kernel to the floppy. A more
flexible (and highly recommended) option is <var class="OPTION">lilo</var>, which will of
course create a lilo boot disk. See LILO in <a href="#BOOTING-LILO">Section 7.1</a> for
more information. Of course, you may also choose to simply <var
class="LITERAL">continue</var>, in which case no boot disk will be made.</p>
<div class="INFORMALFIGURE"><a id="AEN1119" name="AEN1119"></a>
<p><img src="installation/setup-bootdisk-w.png" /></p>
</div>
</div>
<div class="SECT3">
<hr />
<h4 class="SECT3"><a id="AEN1123" name="AEN1123">3.4.8.3 Modem</a></h4>
<p>You will be prompted for modem information. More specifically, you will be asked
whether you have a modem, and if so, what serial port it is on.</p>
<div class="INFORMALFIGURE"><a id="AEN1128" name="AEN1128"></a>
<p><img src="installation/setup-modem-w.png" /></p>
</div>
<p>These next configuration subsections may or may not appear, depending on whether or
not you installed their corresponding packages.</p>
</div>
<div class="SECT3">
<hr />
<h4 class="SECT3"><a id="AEN1133" name="AEN1133">3.4.8.4 Timezone</a></h4>
<p>This one's pretty straightforward: you will be asked what time zone you are in. If you
operate on Zulu time, we are very sorry; the (extremely long) list is alphabetically
ordered, and you're at the bottom.</p>
<div class="INFORMALFIGURE"><a id="AEN1138" name="AEN1138"></a>
<p><img src="installation/setup-timezone-w.png" /></p>
</div>
</div>
<div class="SECT3">
<hr />
<h4 class="SECT3"><a id="AEN1142" name="AEN1142">3.4.8.5 Mouse</a></h4>
<p>This subsection simply asks what kind of mouse you have, and whether you want <tt
class="COMMAND">gpm</tt>(8) console mouse support enabled on bootup.</p>
<div class="INFORMALFIGURE"><a id="AEN1148" name="AEN1148"></a>
<p><img src="installation/setup-mouse-w.png" /></p>
</div>
</div>
<div class="SECT3">
<hr />
<h4 class="SECT3"><a id="AEN1152" name="AEN1152">3.4.8.6 Hardware clock</a></h4>
<p>This subsection asks if your computer's hardware clock is set to Coordinated Universal
Time (UTC or GMT). Most PCs are not, so you should probably say no.</p>
<div class="INFORMALFIGURE"><a id="AEN1155" name="AEN1155"></a>
<p><img src="installation/setup-hardware-clock-w.png" /></p>
</div>
</div>
<div class="SECT3">
<hr />
<h4 class="SECT3"><a id="AEN1159" name="AEN1159">3.4.8.7 Font</a></h4>
<p>The font subsection allows you to choose from a list of custom console fonts.</p>
<div class="INFORMALFIGURE"><a id="AEN1164" name="AEN1164"></a>
<p><img src="installation/setup-font-w.png" /></p>
</div>
</div>
<div class="SECT3">
<hr />
<h4 class="SECT3"><a id="AEN1168" name="AEN1168">3.4.8.8 LILO</a></h4>
<p>Here you are prompted for installation of LILO (the LInux LOader; see <a
href="#BOOTING-LILO">Section 7.1</a> for more information).</p>
<div class="INFORMALFIGURE"><a id="AEN1174" name="AEN1174"></a>
<p><img src="installation/setup-lilo-w.png" /></p>
</div>
<p>If Slackware is to be the only operating system on your computer, <var
class="OPTION">simple</var> should work just fine for you. If you are dual-booting, the
<var class="OPTION">expert</var> option is a better choice. See <a
href="#BOOTING-DUAL">Section 7.3</a> for more information on dual-booting. The third
option, <var class="OPTION">do not install</var>, is not recommended unless you know what
you're doing and have a very good reason for not installing LILO. If you are performing
an expert install, you will be given a choice as to where LILO will be put. You may place
LILO in the MBR (Master Boot Record) of your hard drive, in the superblock of your root
Linux partition, or on a floppy disk.</p>
</div>
<div class="SECT3">
<hr />
<h4 class="SECT3"><a id="AEN1183" name="AEN1183">3.4.8.9 Network</a></h4>
<p>The network configuration subsection is actually <tt class="COMMAND">netconfig</tt>.
See <a href="#NETWORK-CONFIGURATION-NETCONFIG">Section 5.1</a> for more information.</p>
</div>
<div class="SECT3">
<hr />
<h4 class="SECT3"><a id="AEN1190" name="AEN1190">3.4.8.10 X Window Manager</a></h4>
<p>This subsection will allow you to choose a default window manager for X. See <a
href="#X-WINDOW-SYSTEM">Chapter 6</a> for more details on X and window managers.</p>
<div class="INFORMALFIGURE"><a id="AEN1198" name="AEN1198"></a>
<p><img src="installation/setup-xwmconfig-w.png" /></p>
</div>
<p>No matter which packages you installed, the last thing configure will do is ask you
whether you want to go ahead and set a <tt class="USERNAME">root</tt> password. For
security reasons, this is probably a good idea; however, like almost everything else in
Slackware, this is your call.</p>
</div>
</div>
</div>
</div>
<div class="CHAPTER">
<hr />
<h1><a id="SYSTEM-CONFIGURATION" name="SYSTEM-CONFIGURATION"></a>Chapter 4 System
Configuration</h1>
<p>Before you can configure the more advanced parts of your system, it's a good idea to
learn how the system is organized and what commands can be used to search for files and
programs. It's also good to know if you need to compile a custom kernel and what the
steps for doing that are. This chapter will familiarize you with system organization and
configuration files. Then, you can move on to configuring the more advanced parts of the
system.</p>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="SYSTEM-CONFIGURATION-OVERVIEW"
name="SYSTEM-CONFIGURATION-OVERVIEW">4.1 System Overview</a></h2>
<p>It's important to understand how a Linux system is put together before diving into the
various configuration aspects. A Linux system is significantly different from a DOS,
Windows, or Macintosh system (with the exception of the Unix-based Mac OS X), but these
sections will help you get acquainted with the layout so that you can easily configure
your system to meet your needs.</p>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="SYSTEM-CONFIGURATION-LAYOUT"
name="SYSTEM-CONFIGURATION-LAYOUT">4.1.1 File System Layout</a></h3>
<p>The first noticeable difference between Slackware Linux and a DOS or Windows system is
the filesystem. For starters, we do not use drive letters to denote different partitions.
Under Linux, there is one main directory. You can relate this to the <tt
class="DEVICENAME">C:</tt> drive under DOS. Each partition on your system is mounted to a
directory on the main directory. It's kind of like an ever-expanding hard disk.</p>
<p>We call the main directory the root directory, and it's denoted with a single slash
(<tt class="FILENAME">/</tt>). This concept may seem strange, but it actually makes life
easy for you when you want to add more space. For example, let's say you run out of space
on the drive that has <tt class="FILENAME">/home</tt> on it. Most people install
Slackware and make one big root drive. Well, since a partition can be mounted to any
directory, you can simply go to the store and pick up a new hard drive and mount it to
<tt class="FILENAME">/home</tt>. You've now grafted on some more space to your system.
And all without having to move many things around.</p>
<p>Below, you will find descriptions of the major top level directories under
Slackware.</p>
<div class="VARIABLELIST">
<dl>
<dt><tt class="FILENAME">bin</tt></dt>
<dd>
<p>Essential user programs are stored here. These represent the bare minimum set of
programs required for a user to use the system. Things like the shell and the filesystem
commands (<tt class="COMMAND">ls</tt>, <tt class="COMMAND">cp</tt>, and so on) are stored
here. The <tt class="FILENAME">/bin</tt> directory usually doesn't receive modification
after installation. If it does, it's usually in the form of package upgrades that we
provide.</p>
</dd>
<dt><tt class="FILENAME">boot</tt></dt>
<dd>
<p>Files that are used by the Linux Loader (LILO). This directory also receives little
modification after an installation. The kernel is stored here as of Slackware 8.1. In
earlier releases of Slackware, the kernel was simply stored under <tt
class="FILENAME">/</tt> , but common practice is to put the kernel and related files here
to facilitate dual-booting.</p>
</dd>
<dt><tt class="FILENAME">dev</tt></dt>
<dd>
<p>Everything in Linux is treated as a file, even hardware devices like serial ports,
hard disks, and scanners. In order to access these devices, a special file called a
device node has to be present. All device nodes are stored in the <tt
class="FILENAME">/dev</tt> directory. You will find this to be true across many Unix-like
operating systems.</p>
</dd>
<dt><tt class="FILENAME">etc</tt></dt>
<dd>
<p>This directory holds system configuration files. Everything from the X Window
configuration file, the user database, to the system startup scripts. The system
administrator will become quite familiar with this directory over time.</p>
</dd>
<dt><tt class="FILENAME">home</tt></dt>
<dd>
<p>Linux is a multiuser operating system. Each user on the system is given an account and
a unique directory for personal files. This directory is called the user's home
directory. The <tt class="FILENAME">/home</tt> directory is provided as the default
location for user home directories.</p>
</dd>
<dt><tt class="FILENAME">lib</tt></dt>
<dd>
<p>System libraries that are required for basic operation are stored here. The C library,
the dynamic loader, the ncurses library, and kernel modules are among the things stored
here.</p>
</dd>
<dt><tt class="FILENAME">mnt</tt></dt>
<dd>
<p>This directory contains temporary mount points for working on hard disks or removable
drives. Here you'll find mount points for your CD-ROM and floppy drives.</p>
</dd>
<dt><tt class="FILENAME">opt</tt></dt>
<dd>
<p>Optional software packages. The idea behind <tt class="FILENAME">/opt</tt> is that
each software package installs to <tt class="FILENAME">/opt/<var
class="REPLACEABLE">software-package</var></tt>, which makes it easy to remove later.
Slackware distributes some things in <tt class="FILENAME">/opt</tt> (such as KDE in <tt
class="FILENAME">/opt/kde</tt>), but you are free to add anything you want to <tt
class="FILENAME">/opt</tt>.</p>
</dd>
<dt><tt class="FILENAME">proc</tt></dt>
<dd>
<p>This is a unique directory. It's not really part of the filesystem, but a virtual
filesystem that provides access to kernel information. Various pieces of information that
the kernel wants you to know are conveyed to you through files in the <tt
class="FILENAME">/proc</tt> directory. You can also send information to the kernel
through some of these files. Try doing <tt class="COMMAND">cat /proc/cpuinfo</tt>.</p>
</dd>
<dt><tt class="FILENAME">root</tt></dt>
<dd>
<p>The system administrator is known as <tt class="USERNAME">root</tt> on the system. <tt
class="USERNAME">root</tt>'s home directory is kept in <tt class="FILENAME">/root</tt>
instead of <tt class="FILENAME">/home/root</tt>. The reason is simple. What if <tt
class="FILENAME">/home</tt> was a different partition from <tt class="FILENAME">/</tt>
and it could not be mounted? <tt class="USERNAME">root</tt> would naturally want to log
in and repair the problem. If his home directory was on the damaged filesystem, it would
make it difficult for him to log in.</p>
</dd>
<dt><tt class="FILENAME">sbin</tt></dt>
<dd>
<p>Essential programs that are run by <tt class="USERNAME">root</tt> and during the
system bootup process are kept here. Normal users will not run programs in this
directory.</p>
</dd>
<dt><tt class="FILENAME">tmp</tt></dt>
<dd>
<p>The temporary storage location. All users have read and write access to this
directory.</p>
</dd>
<dt><tt class="FILENAME">usr</tt></dt>
<dd>
<p>This is the big directory on a Linux system. Everything else pretty much goes here,
programs, documentation, the kernel source code, and the X Window system. This is the
directory to which you will most likely be installing programs.</p>
</dd>
<dt><tt class="FILENAME">var</tt></dt>
<dd>
<p>System log files, cache data, and program lock files are stored here. This is the
directory for frequently-changing data.</p>
</dd>
</dl>
</div>
<p>You should now have a good feel for which directories contain what on the filesystem.
More detailed information about the filesystem layout is available in the hier(7) man
page. The next section will help you find specific files easily, so you don't have to do
it by hand.</p>
</div>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="SYSTEM-CONFIGURATION-FINDING"
name="SYSTEM-CONFIGURATION-FINDING">4.1.2 Finding Files</a></h3>
<p>You now know what each major directory holds, but it still doesn't really help you
find things. I mean, you could go looking through directories, but there are quicker
ways. There are four main file search commands available in Slackware.</p>
<div class="SECT3">
<hr />
<h4 class="SECT3"><a id="AEN1329" name="AEN1329">4.1.2.1 <tt
class="COMMAND">which</tt></a></h4>
<p>The first is the <tt class="COMMAND">which</tt>(1) command. <tt
class="COMMAND">which</tt> is usually used to locate a program quickly. It just searches
your <tt class="ENVAR">PATH</tt> and returns the first instance it finds and the
directory path to it. Take this example:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">which bash</kbd>
/bin/bash
</pre>
</td>
</tr>
</table>
<p>From that you see that <tt class="COMMAND">bash</tt> is in the <tt
class="FILENAME">/bin</tt> directory. This is a very limited command for searching, since
it only searches your <tt class="ENVAR">PATH</tt>.</p>
</div>
<div class="SECT3">
<hr />
<h4 class="SECT3"><a id="AEN1347" name="AEN1347">4.1.2.2 <tt
class="COMMAND">whereis</tt></a></h4>
<p>The <tt class="COMMAND">whereis</tt>(1) command works similar to <tt
class="COMMAND">which</tt>, but can also search for man pages and source files. A <tt
class="COMMAND">whereis</tt> search for <tt class="COMMAND">bash</tt> should return
this:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">whereis bash</kbd>
bash: /bin/bash /usr/bin/bash /usr/man/man1/bash.1.gz
</pre>
</td>
</tr>
</table>
<p>This command not only told us where the actual program is located, but also where the
online documentation is stored. Still, this command is limited. What if you wanted to
search for a specific configuration file? You can't use <tt class="COMMAND">which</tt> or
<tt class="COMMAND">whereis</tt> for that.</p>
</div>
<div class="SECT3">
<hr />
<h4 class="SECT3"><a id="AEN1363" name="AEN1363">4.1.2.3 <tt
class="COMMAND">find</tt></a></h4>
<p>The <tt class="COMMAND">find</tt>(1) command allows the user to search the filesystem
with a rich collection of search predicates. Users may specify a search with filename
wildcards, ranges of modification or creation times, or other advanced properties. For
example, to search for the default <tt class="FILENAME">xinitrc</tt> file on the system,
the following command could be used.</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">find / -name xinitrc</kbd>
/var/X11R6/lib/xinit/xinitrc
</pre>
</td>
</tr>
</table>
<p><tt class="COMMAND">find</tt> will take a while to run, since it has to traverse the
entire root directory tree. And if this command is run as a normal user, there will be
permission denied error messages for directories that only <tt class="USERNAME">root</tt>
can see. But <tt class="COMMAND">find</tt> found our file, so that's good. If only it
could be a bit faster...</p>
</div>
<div class="SECT3">
<hr />
<h4 class="SECT3"><a id="AEN1378" name="AEN1378">4.1.2.4 <tt
class="COMMAND">slocate</tt></a></h4>
<p>The <tt class="COMMAND">slocate</tt>(1) command searches the entire filesystem, just
like the find command can do, but it searches a database instead of the actual
filesystem. The database is set to automatically update every morning, so you have a
somewhat fresh listing of files on your system. You can manually run <tt
class="COMMAND">updatedb</tt>(1) to update the slocate database (before running <tt
class="COMMAND">updatedb</tt> by hand, you must first <tt class="COMMAND">su</tt> to the
<tt class="USERNAME">root</tt> user). Here's an example of <tt
class="COMMAND">slocate</tt> in action:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd
class="USERINPUT">slocate xinitrc</kbd> # we don't have to go to the root
/var/X11R6/lib/xinit/xinitrc
/var/X11R6/lib/xinit/xinitrc.fvwm2
/var/X11R6/lib/xinit/xinitrc.openwin
/var/X11R6/lib/xinit/xinitrc.twm
</pre>
</td>
</tr>
</table>
<p>We got more than what we were looking for, and quickly too. With these commands, you
should be able to find whatever you're looking for on your Linux system.</p>
</div>
</div>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="SYSTEM-CONFIGURATION-RCD" name="SYSTEM-CONFIGURATION-RCD">4.1.3
The <tt class="FILENAME">/etc/rc.d</tt> Directory</a></h3>
<p>The system initialization files are stored in the <tt class="FILENAME">/etc/rc.d</tt>
directory. Slackware uses the BSD-style layout for its initialization files as opposed to
System V init scripts, which tend to make configuration changes much more difficult
without using a program specifically designed for that purpose. In BSD-init scripts, each
runlevel is given a single rc file. In System V, each runlevel is given its own
directory, each containing numerous init scripts. This provides an organized structure
that is easy to maintain.</p>
<p>There are several categories of initialization files. These are system startup,
runlevels, network initialization, and System V compatibility. As per tradition, we'll
lump everything else into another category.</p>
<div class="SECT3">
<hr />
<h4 class="SECT3"><a id="AEN1406" name="AEN1406">4.1.3.1 System Startup</a></h4>
<p>The first program to run under Slackware besides the Linux kernel is <tt
class="COMMAND">init</tt>(8). This program reads the <tt
class="FILENAME">/etc/inittab</tt>(5) file to see how to run the system. It runs the <tt
class="FILENAME">/etc/rc.d/rc.S</tt> script to prepare the system before going into your
desired runlevel. The <tt class="FILENAME">rc.S</tt> file enables your virtual memory,
mounts your filesystems, cleans up certain log directories, initializes Plug and Play
devices, loads kernel modules, configures PCMCIA devices, sets up serial ports, and runs
System V init scripts (if found). Obviously <tt class="FILENAME">rc.S</tt> has a lot on
its plate, but here are some scripts in <tt class="FILENAME">/etc/rc.d</tt> that <tt
class="FILENAME">rc.S</tt> will call on to complete its work:</p>
<div class="VARIABLELIST">
<dl>
<dt><tt class="FILENAME">rc.S</tt></dt>
<dd>
<p>This is the actual system initialization script.</p>
</dd>
<dt><tt class="FILENAME">rc.modules</tt></dt>
<dd>
<p>Loads kernel modules. Things like your network card, PPP support, and other things are
loaded here. If this script finds <tt class="FILENAME">rc.netdevice</tt>, it will run
that as well.</p>
</dd>
<dt><tt class="FILENAME">rc.pcmcia</tt></dt>
<dd>
<p>Probes for and configures any PCMCIA devices that you might have on your system. This
is most useful for laptop users, who probably have a PCMCIA modem or network card.</p>
</dd>
<dt><tt class="FILENAME">rc.serial</tt></dt>
<dd>
<p>Configures your serial ports by running the appropriate <tt
class="COMMAND">setserial</tt> commands.</p>
</dd>
<dt><tt class="FILENAME">rc.sysvinit</tt></dt>
<dd>
<p>Looks for System V init scripts for the desired runlevel and runs them. This is
discussed in more detail below.</p>
</dd>
</dl>
</div>
</div>
<div class="SECT3">
<hr />
<h4 class="SECT3"><a id="AEN1454" name="AEN1454">4.1.3.2 Runlevel Initialization
Scripts</a></h4>
<p>After system initialization is complete, <tt class="COMMAND">init</tt> moves on to
runlevel initialization. A runlevel describes the state that your machine will be running
in. Sound redundant? Well, the runlevel tells <tt class="COMMAND">init</tt> if you will
be accepting multiuser logins or just a single user, whether or not you want network
services, and if you will be using the X Window System or <tt
class="COMMAND">agetty</tt>(8) to handle logins. The files below define the different
runlevels in Slackware Linux.</p>
<div class="VARIABLELIST">
<dl>
<dt><tt class="FILENAME">rc.0</tt></dt>
<dd>
<p>Halt the system (runlevel 0). By default, this is symlinked to <tt
class="FILENAME">rc.6</tt>.</p>
</dd>
<dt><tt class="FILENAME">rc.4</tt></dt>
<dd>
<p>Multiuser startup (runlevel 4), but in X11 with KDM, GDM, or XDM as the login
manager.</p>
</dd>
<dt><tt class="FILENAME">rc.6</tt></dt>
<dd>
<p>Reboot the system (runlevel 6).</p>
</dd>
<dt><tt class="FILENAME">rc.K</tt></dt>
<dd>
<p>Startup in single user mode (runlevel 1).</p>
</dd>
<dt><tt class="FILENAME">rc.M</tt></dt>
<dd>
<p>Multiuser mode (runlevels 2 and 3), but with the standard text-based login. This is
the default runlevel in Slackware.</p>
</dd>
</dl>
</div>
</div>
<div class="SECT3">
<hr />
<h4 class="SECT3"><a id="AEN1493" name="AEN1493">4.1.3.3 Network Initialization</a></h4>
<p>Runlevels 2, 3, and 4 will start up the network services. The following files are
responsible for the network initialization:</p>
<div class="VARIABLELIST">
<dl>
<dt><tt class="FILENAME">rc.inet1</tt></dt>
<dd>
<p>Created by <tt class="COMMAND">netconfig</tt>, this file is responsible for
configuring the actual network interface.</p>
</dd>
<dt><tt class="FILENAME">rc.inet2</tt></dt>
<dd>
<p>Runs after <tt class="FILENAME">rc.inet1</tt> and starts up basic network
services.</p>
</dd>
<dt><tt class="FILENAME">rc.atalk</tt></dt>
<dd>
<p>Starts up AppleTalk services.</p>
</dd>
<dt><tt class="FILENAME">rc.httpd</tt></dt>
<dd>
<p>Starts up the Apache web server. Like a few other rc scripts, this one can also be
used to stop and restart a service. <tt class="FILENAME">rc.httpd</tt> takes arguments of
stop, start, or restart. </p>
</dd>
<dt><tt class="FILENAME">rc.news</tt></dt>
<dd>
<p>Starts up the news server.</p>
</dd>
</dl>
</div>
</div>
<div class="SECT3">
<hr />
<h4 class="SECT3"><a id="AEN1534" name="AEN1534">4.1.3.4 System V Compatibility</a></h4>
<p>System V init compatibility was introduced in Slackware 7.0. Many other Linux
distributions make use of this style instead of the BSD style. Basically each runlevel is
given a subdirectory for init scripts, whereas BSD style gives one init script to each
runlevel.</p>
<p>The <tt class="FILENAME">rc.sysvinit</tt> script will search for any System V init
scripts you have in <tt class="FILENAME">/etc/rc.d</tt> and run them, if the runlevel is
appropriate. This is useful for certain commercial software packages that install System
V init scripts</p>
</div>
<div class="SECT3">
<hr />
<h4 class="SECT3"><a id="AEN1546" name="AEN1546">4.1.3.5 Other Files</a></h4>
<p>The scripts described below are the other system initialization scripts. They are
typically run from one of the major scripts above, so all you need to do is edit the
contents.</p>
<div class="VARIABLELIST">
<dl>
<dt><tt class="FILENAME">rc.gpm</tt></dt>
<dd>
<p>Starts up general purpose mouse services. Allows you to copy and paste at the Linux
console. Occasionally, gpm will cause problems with the mouse when it is used under X
windows. If you experience problems with the mouse under X, try taking away the
executable permission from this file and stopping the gpm server.</p>
</dd>
<dt><tt class="FILENAME">rc.font</tt></dt>
<dd>
<p>Loads the custom screen font for the console.</p>
</dd>
<dt><tt class="FILENAME">rc.local</tt></dt>
<dd>
<p>Contains any specific startup commands for your system. This is empty after a fresh
install, as it is reserved for local administrators. This script is run after all other
initialization has taken place.</p>
</dd>
</dl>
</div>
<p>To enable a script, all you need to do is add the execute permissions to it with the
<tt class="COMMAND">chmod</tt> command. To disable a script, remove the execute
permissions from it. For more information about <tt class="COMMAND">chmod</tt>, see <a
href="#FILESYSTEM-STRUCTURE-PERMISSIONS">Section 9.2</a>.</p>
</div>
</div>
</div>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="SYSTEM-CONFIGURATION-KERNEL"
name="SYSTEM-CONFIGURATION-KERNEL">4.2 Selecting a Kernel</a></h2>
<p>The kernel is the part of the operating system that provides hardware access, process
control, and overall system control. The kernel contains support for your hardware
devices, so picking one for your system is an important setup step.</p>
<p>Slackware provides more than a dozen precompiled kernels that you can pick from, each
with a standard set of drivers and additional specific drivers. You can run one of the
precompiled kernels or you can build your own kernel from source. Either way, you need to
make sure that your kernel has the hardware support your system needs.</p>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="AEN1581" name="AEN1581">4.2.1 The <tt
class="FILENAME">/kernels</tt> Directory on the Slackware CD-ROM</a></h3>
<p>The precompiled Slackware kernels are available in the <tt
class="FILENAME">/kernels</tt> directory on the Slackware CD-ROM or on the FTP site in
the main Slackware directory. The available kernels change as new releases are made, so
the documentation in that directory is always the authoritative source. The <tt
class="FILENAME">/kernels</tt> directory has subdirectories for each kernel available.
The subdirectories have the same name as their accompanying boot disk. In each
subdirectory you will find the following files:</p>
<div class="INFORMALTABLE"><a id="AEN1587" name="AEN1587"></a>
<table border="0" frame="void" width="100%" class="CALSTABLE">
<col width="33%" />
<col width="67%" />
<thead>
<tr>
<th>File</th>
<th>Purpose</th>
</tr>
</thead>
<tbody>
<tr>
<td><tt class="FILENAME">System.map</tt></td>
<td>The system map file for this kernel</td>
</tr>
<tr>
<td><tt class="FILENAME">bzImage</tt></td>
<td>The actual kernel image</td>
</tr>
<tr>
<td><tt class="FILENAME">config</tt></td>
<td>The source configuration file for this kernel</td>
</tr>
</tbody>
</table>
</div>
<p>To use a kernel, copy the <tt class="FILENAME">System.map</tt> and <tt
class="FILENAME">config</tt> files to your <tt class="FILENAME">/boot</tt> directory and
copy the kernel image to <tt class="FILENAME">/boot/vmlinuz</tt>. Run <tt
class="COMMAND">/sbin/lilo</tt>(8) to install LILO for the new kernel, and then reboot
your system. That's all there is to installing a new kernel.</p>
<p>The kernels that end with a .i are IDE kernels. That is, they include no SCSI support
in the base kernel. The kernels that end with .s are SCSI kernels. They include all the
IDE support in .i kernels, plus SCSI support.</p>
</div>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="SYSTEM-CONFIGURATION-KERNEL-COMPILE"
name="SYSTEM-CONFIGURATION-KERNEL-COMPILE">4.2.2 Compiling a Kernel from Source</a></h3>
<p>The question “Should I compile a kernel for my system?” is often asked by
new users. The answer is a definite maybe. There are few instances where you will need to
compile a kernel specific to your system. Most users can use a precompiled kernel and the
loadable kernel modules to achieve a fully working system. You will want to compile a
kernel for your system if you are upgrading kernel versions to one that we do not
currently offer in Slackware, or if you have patched the kernel source to get special
device support that is not in the native kernel source. Anyone with an SMP system will
definitely want to compile a kernel with SMP support. Also, many users find a custom
compiled kernel runs much faster on their machine. You may find it useful to compile the
kernel with optimizations for the specific processor in your machine.</p>
<p>Building your own kernel is not that hard. The first step is to make sure you have the
kernel source installed on your system. Make sure that you installed the packages from
the K series during the installation. You will also want to make sure you have the D
series installed, specifically the C compiler, GNU make, and GNU binutils. In general,
it's a good idea to have the entire D series installed if you plan on doing any kind of
development. You can also download the latest kernel source from <a
href="http://www.kernel.org/mirrors" target="_top">http://www.kernel.org/mirrors</a>.</p>
<div class="SECT3">
<hr />
<h4 class="SECT3"><a id="AEN1624" name="AEN1624">4.2.2.1 Linux Kernel version 2.4.x
Compilation</a></h4>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">su -</kbd>
Password:
<samp class="PROMPT">#</samp> <kbd class="USERINPUT">cd /usr/src/linux</kbd>
</pre>
</td>
</tr>
</table>
<p>The first step is to bring the kernel source into its base state. We issue this
command to do that (note, you may wish to back-up the <tt class="FILENAME">.config</tt>
file as this command will delete it without warning):</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">#</samp> <kbd class="USERINPUT">make mrproper</kbd>
</pre>
</td>
</tr>
</table>
<p>Now you can configure the kernel for your system. The current kernel offers three ways
of doing this. The first is the original text-based question and answer system. It asks a
bunch of questions and then builds a configuration file. The problem with this method is
that if you mess up, you must start over. The method that most people prefer is the menu
driven one. Lastly, there is an X-based kernel configuration tool. Pick the one you want
and issue the appropriate command:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">#</samp> <kbd
class="USERINPUT">make config</kbd> (text-based Q&A version)
<samp class="PROMPT">#</samp> <kbd
class="USERINPUT">make menuconfig</kbd> (menu driven, text-based version)
<samp class="PROMPT">#</samp> <kbd
class="USERINPUT">make xconfig</kbd> (X-based version, make sure you are in X first)
</pre>
</td>
</tr>
</table>
<div class="FIGURE"><a id="SYSTEM-CONFIGURATION-MAKE-MENUCONFIG"
name="SYSTEM-CONFIGURATION-MAKE-MENUCONFIG"></a>
<p><b>Figure 4-1. Kernel Configuration Menu</b></p>
<p><img src="system-configuration/make-menuconfig-w.png" /></p>
</div>
<p>New users will probably find <tt class="COMMAND">menuconfig</tt> to be the easiest to
use. Help screens are provided that explain the various parts of the kernel. After
configuring your kernel, exit the configuration program. It will write the necessary
configuration files. Now we can prepare the source tree for a build:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">#</samp> <kbd class="USERINPUT">make dep</kbd>
<samp class="PROMPT">#</samp> <kbd class="USERINPUT">make clean</kbd>
</pre>
</td>
</tr>
</table>
<p>The next step is to compile the kernel. First try issuing the <tt
class="COMMAND">bzImage</tt> command below.</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">#</samp> <kbd class="USERINPUT">make bzImage</kbd>
</pre>
</td>
</tr>
</table>
<p>This may take a while, depending on your CPU speed. During the build process, you will
see the compiler messages. After building the kernel image, you will want to build any
parts of the kernel that you flagged as modular.</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">#</samp> <kbd class="USERINPUT">make modules</kbd>
</pre>
</td>
</tr>
</table>
<p>We can now install the kernel and modules that you compiled. To install the kernel on
a Slackware system, these commands should be issued:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">#</samp> <kbd
class="USERINPUT">mv /boot/vmlinuz /boot/vmlinuz.old</kbd>
<samp class="PROMPT">#</samp> <kbd
class="USERINPUT">cat arch/i386/boot/bzImage > /vmlinuz</kbd>
<samp class="PROMPT">#</samp> <kbd
class="USERINPUT">mv /boot/System.map /boot/System.map.old</kbd>
<samp class="PROMPT">#</samp> <kbd class="USERINPUT">cp System.map /boot/System.map</kbd>
<samp class="PROMPT">#</samp> <kbd class="USERINPUT">make modules_install</kbd>
</pre>
</td>
</tr>
</table>
<p>You will want to edit <tt class="FILENAME">/etc/lilo.conf</tt> and add a section to
boot your old kernel in case your new one does not work. After doing that, run <tt
class="COMMAND">/sbin/lilo</tt> to install the new boot block. You can now reboot with
your new kernel.</p>
</div>
<div class="SECT3">
<hr />
<h4 class="SECT3"><a id="AEN1686" name="AEN1686">4.2.2.2 Linux Kernel Version
2.6.x</a></h4>
<p>The compilation of a 2.6 kernel is only slightly different from a 2.4 or a 2.2 kernel,
but it is important that you understand the differences before delving in. It's no longer
necessary to run <tt class="COMMAND">make dep</tt> and <tt class="COMMAND">make
clean</tt>. Also, the kernel compilation process is not as verbose in the 2.6 kernel
series. This results in a build process that is easier to understand, but has some short
comings as well. If you have trouble building the kernel, it's highly recommended that
you turn verbosity back up. You do this simply by appending <var class="OPTION">V=1</var>
to the build. This allows you to log more information that could help a kernel developer
or other friendly geek aid you in resolving the issue.</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">#</samp> <kbd class="USERINPUT">make bzImage V=1</kbd>
</pre>
</td>
</tr>
</table>
</div>
</div>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="SYSTEM-CONFIGURATION-KERNEL-MODULES"
name="SYSTEM-CONFIGURATION-KERNEL-MODULES">4.2.3 Using Kernel Modules</a></h3>
<p>Kernel modules are another name for device drivers that can be inserted into a running
kernel. They allow you to extend the hardware supported by your kernel without needing to
pick another kernel or compile one yourself.</p>
<p>Modules can also be loaded and unloaded at any time, even when the system is running.
This makes upgrading specific drivers easy for system administrators. A new module can be
compiled, the old one removed, and the new one loaded, all without rebooting the
machine.</p>
<p>Modules are stored in the <tt class="FILENAME">/lib/modules/<var
class="REPLACEABLE">kernel version</var></tt> directory on your system. They can be
loaded at boot time through the <tt class="FILENAME">rc.modules</tt> file. This file is
very well commented and offers examples for major hardware components. To see a list of
modules that are currently active, use the <tt class="COMMAND">lsmod</tt>(1) command:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">#</samp> <kbd class="USERINPUT">lsmod</kbd>
Module Size Used by
parport_pc 7220 0
parport 7844 0 [parport_pc]
</pre>
</td>
</tr>
</table>
<p>You can see here that I only have the parallel port module loaded. To remove a module,
you use the <tt class="COMMAND">rmmod</tt>(1) command. Modules can be loaded by the <tt
class="COMMAND">modprobe</tt>(1) or <tt class="COMMAND">insmod</tt>(1) command. <tt
class="COMMAND">modprobe</tt> is usually safer because it will load any modules that the
one you're trying to load depends on.</p>
<p>A lot of users never have to load or unload modules by hand. They use the kernel
autoloader for module management. By default, Slackware includes <var
class="OPTION">kmod</var> in its kernels. <var class="OPTION">kmod</var> is a kernel
option that enables the kernel to automatically load modules as they are requested. For
more information on <var class="OPTION">kmod</var> and how it is configured, see <tt
class="FILENAME">/usr/src/linux/Documentation/kmod.txt</tt>. You'll have needed to have
the kernel source package, or downloaded kernel source from <a href="http://kernel.org"
target="_top">http://kernel.org</a>.</p>
<p>More information can be found in the man pages for each of these commands, plus the
<tt class="FILENAME">rc.modules</tt> file.</p>
</div>
</div>
</div>
<div class="CHAPTER">
<hr />
<h1><a id="NETWORK-CONFIGURATION" name="NETWORK-CONFIGURATION"></a>Chapter 5 Network
Configuration</h1>
<div class="SECT1">
<h2 class="SECT1"><a id="NETWORK-CONFIGURATION-NETCONFIG"
name="NETWORK-CONFIGURATION-NETCONFIG">5.1 Introduction: netconfig is your
friend.</a></h2>
<p>When you initially installed Slackware, the setup program invoked the <tt
class="COMMAND">netconfig</tt> program. <tt class="COMMAND">netconfig</tt> attempted to
perform the following functions for you:</p>
<ul>
<li>
<p>It asked you for the name of your computer, and the domain name for your computer.</p>
</li>
<li>
<p>It gave a brief explanation of the various types of addressing schemes, told when they
should be used, and asked you which IP addressing scheme you wished to use to configure
your network card:</p>
<ul>
<li>
<p>Static-IP</p>
</li>
<li>
<p>DHCP</p>
</li>
<li>
<p>Loopback</p>
</li>
</ul>
<br />
<br />
</li>
<li>
<p>It then offered to probe for a network card to configure.</p>
</li>
</ul>
<p><tt class="COMMAND">netconfig</tt> will generally take care of about 80% of the work
of configuring your LAN network connection if you will let it. Note that I would strongly
suggest that you review your config file for a couple of reasons:</p>
<ol type="1">
<li>
<p>You should never trust a setup program to properly configure your computer. If you use
a setup program, you should review the configuration yourself.</p>
</li>
<li>
<p>If you are still learning Slackware and Linux system management, viewing a working
configuration can be helpful. You'll at least know what the configuration should look
like. This will allow you to correct problems due to misconfiguration of the system at a
later date.</p>
</li>
</ol>
</div>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="NETWORK-CONFIGURATION-HARDWARE"
name="NETWORK-CONFIGURATION-HARDWARE">5.2 Network Hardware Configuration</a></h2>
<p>Having decided that you wish to bring your Slackware machine on to some form of
network, the first thing you'll need is a Linux-compatible network card. You will need to
take a little care to ensure that the card is truly Linux-compatible (please refer to the
Linux Documentation Project and/or the kernel documentation for information on the
current status of your proposed network card). As a general rule, you will most likely be
pleasantly surprised by the number of networking cards that are supported under the more
modern kernels. Having said that, I'd still suggest referring to any of the various Linux
hardware compatibility lists (such as <a
href="http://www.eskimo.com/%7Elo/linux/hardwarelinks.html" target="_top">The GNU/Linux
Beginners Group Hardware Compatibility Links</a> and <a
href="http://www.linux.org/docs/ldp/howto/Hardware-HOWTO/" target="_top">The Linux
Documentation Project Hardware HOWTO</a>) that are available on the Internet before
purchasing your card. A little extra time spent in research can save days or even weeks
trying to troubleshoot a card that isn't compatible with Linux at all.</p>
<p>When you visit the Linux Hardware Compatibility lists available on the Internet, or
when you refer to the kernel documentation installed on your machine, it would be wise to
note which kernel module you'll need to use to support your network card.</p>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="NETWORK-CONFIGURATION-HARDWARE-MODULES"
name="NETWORK-CONFIGURATION-HARDWARE-MODULES">5.2.1 Loading Network Modules</a></h3>
<p>Kernel modules that are to be loaded on boot-up are loaded from the <tt
class="FILENAME">rc.modules</tt> file in <tt class="FILENAME">/etc/rc.d</tt> or by the
kernel's auto module loading started by <tt class="FILENAME">/etc/rc.d/rc.hotplug</tt>.
The default <tt class="FILENAME">rc.modules</tt> file includes a Network device support
section. If you open <tt class="FILENAME">rc.modules</tt> and look for that section,
you'll notice that it first checks for an executable <tt
class="FILENAME">rc.netdevice</tt> file in <tt class="FILENAME">/etc/rc.d/</tt>. This
script is created if <tt class="COMMAND">setup</tt> successfully autoprobes your network
device during installation.</p>
<p>Below that “if” block is a list of network devices and modprobe lines,
each commented out. Find your device and uncomment the corresponding modprobe line, then
save the file. Running <tt class="FILENAME">rc.modules</tt> as <tt
class="USERNAME">root</tt> should now load your network device driver (as well as any
other modules that are listed and uncommented). Note that some modules (such as the
ne2000 driver) require parameters; make sure you select the correct line.</p>
</div>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="NETWORK-CONFIGURATION-HARDWARE-LAN"
name="NETWORK-CONFIGURATION-HARDWARE-LAN">5.2.2 LAN (10/100/1000Base-T and Base-2)
cards</a></h3>
<p>This heading encompasses all of the internal PCI and ISA networking cards. Drivers for
these cards are provided via loadable kernel modules as covered in the previous
paragraph. <tt class="FILENAME">/sbin/netconfig</tt> should have probed for your card and
successfully set up your <tt class="FILENAME">rc.netdevice</tt> file. If this did not
occur, the most likely problem would be that the module that you're attempting to load
for a given card is incorrect (it is not unheard of for different generations of the same
brand of card from the same manufacturer to require different modules). If you are
certain that the module that you're attempting to load is the correct one, your next best
bet would be to refer to the documentation for the module in an attempt to discover
whether or not specific parameters are required during when the module is
initialized.</p>
</div>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="NETWORK-CONFIGURATION-HARDWARE-MODEMS"
name="NETWORK-CONFIGURATION-HARDWARE-MODEMS">5.2.3 Modems</a></h3>
<p>Like LAN cards, modems can come with various bus support options. Until recently, most
modems were 8 or 16 bit ISA cards. With the efforts of Intel and motherboard
manufacturers everywhere to finally kill off the ISA bus completely, it is common now to
find that most modems are either external modems that connect to a serial or USB port or
are internal PCI modems. If you wish for your modem to work with Linux, it is <span
class="emphasis"><i class="EMPHASIS">VITALLY</i></span> important to research your
prospective modem purchase, particularly if you are considering purchasing a PCI modem.
Many, if not most, PCI modems available on store shelves these days are WinModems.
WinModems lack some basic hardware on the modem card itself: the functions performed by
this hardware are typically offloaded onto the CPU by the modem driver and the Windows
operating system. This means that they do not have the standard serial interface that
PPPD will be expecting to see when you try to dial out to your Internet Service
Provider.</p>
<p>If you want to be absolutely sure that the modem you're purchasing will work with
Linux, purchase an external hardware modem that connects to the serial port on your PC.
These are guaranteed to work better and be less trouble to install and maintain, though
they require external power and tend to cost more.</p>
<p>There are several web sites that provide drivers and assistance for configuring
WinModem based devices. Some users have reported success configuring and installing
drivers for the various winmodems, including Lucent, Conexant, and Rockwell chipsets. As
the required software for these devices is not an included part of Slackware, and varies
from driver to driver, we will not go into detail on them.</p>
</div>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="NETWORK-CONFIGURATION-HARDWARE-PCMCIA"
name="NETWORK-CONFIGURATION-HARDWARE-PCMCIA">5.2.4 PCMCIA</a></h3>
<p>As part of your Slackware install, you are given the opportunity to install the pcmcia
package (in the “A” series of packages). This package contains the
applications and setup files required to work with PCMCIA cards under Slackware. It is
important to note that the pcmcia package only installs the generic software required to
work with PCMCIA cards under Slackware. It does NOT install any drivers or modules. The
available modules and drivers will be in the <tt class="FILENAME">/lib/modules/`uname
-r`/pcmcia</tt> directory. You may need to do some experimentation to find a module that
will work with your network card.</p>
<p>You will need to edit <tt class="FILENAME">/etc/pcmcia/network.opts</tt> (for an
Ethernet card) or <tt class="FILENAME">/etc/pcmcia/wireless.opts</tt> (if you have a
wireless networking card). Like most Slackware configuration files, these two files are
very well commented and it should be easy to determine which modifications need to be
made.</p>
</div>
</div>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="NETWORK-CONFIGURATION-TCPIP"
name="NETWORK-CONFIGURATION-TCPIP">5.3 TCP/IP Configuration</a></h2>
<p>At this point, your network card should be physically installed in your computer, and
the relevant kernel modules should be loaded. You will not yet be able to communicate
over your network card, but information about the network device can be obtained with <tt
class="COMMAND">ifconfig -a</tt>.</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">#</samp> <kbd class="USERINPUT">ifconfig -a</kbd>
eth0 Link encap:Ethernet HWaddr 00:A0:CC:3C:60:A4
UP BROADCAST NOTRAILERS RUNNING MULTICAST MTU:1500 Metric:1
RX packets:110081 errors:1 dropped:0 overruns:0 frame:0
TX packets:84931 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:100
RX bytes:114824506 (109.5 Mb) TX bytes:9337924 (8.9 Mb)
Interrupt:5 Base address:0x8400
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:2234 errors:0 dropped:0 overruns:0 frame:0
TX packets:2234 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:168758 (164.8 Kb) TX bytes:168758 (164.8 Kb)
</pre>
</td>
</tr>
</table>
<p>If you just typed <tt class="COMMAND">/sbin/ifconfig</tt> without the <var
class="OPTION">-a</var> suffix, you would not see the <tt class="FILENAME">eth0</tt>
interface, as your network card does not yet have a valid IP address or route.</p>
<p>While there are many different ways to setup and subnet a network, all of them can be
broken down into two types: Static and Dynamic. Static networks are setup such that each
node (geek lingo for thing with an IP address) always has the same IP address. Dynamic
networks are setup in such a way that the IP addresses for the nodes are controlled by a
single server called the DHCP server.</p>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="NETWORK-CONFIGURATION-TCPIP-DHCP"
name="NETWORK-CONFIGURATION-TCPIP-DHCP">5.3.1 DHCP</a></h3>
<p>DHCP (or Dynamic Host Configuration Protocol), is a means by which an IP address may
be assigned to a computer on boot. When the DHCP <span class="emphasis"><i
class="EMPHASIS">client</i></span> boots, it puts out a request on the Local Area Network
for a DHCP <span class="emphasis"><i class="EMPHASIS">server</i></span> to assign it an
IP address. The DHCP server has a pool (or <span class="emphasis"><i
class="EMPHASIS">scope</i></span>) of IP addresses available. The server will respond to
this request with an IP address from the pool, along with a <span class="emphasis"><i
class="EMPHASIS">lease time</i></span>. Once the lease time for a given IP address lease
has expired, the client must contact the server again and repeat the negotiation.</p>
<p>The client will then accept the IP address from the server and will configure the
requested interface with the IP address. There is one more handy trick that DHCP clients
use for negotiating the IP address that they will be assigned, however. The client will
remember it's last assigned IP address, and will request that the server re-assign that
IP address to the client again upon next negotiation. If possible, the server will do so,
but if not, a new address is assigned. So, the negotiation resembles the following:</p>
<p class="LITERALLAYOUT"> <span class="emphasis"><i
class="EMPHASIS">Client</i></span>: Is there a DHCP server available on the LAN?<br />
<span class="emphasis"><i
class="EMPHASIS">Server</i></span>: Yes, there is. Here I am.<br />
<span class="emphasis"><i
class="EMPHASIS">Client</i></span>: I need an IP address.<br />
<span class="emphasis"><i
class="EMPHASIS">Server</i></span>: You may take 192.168.10.10 for 19200 seconds.<br />
<span class="emphasis"><i
class="EMPHASIS">Client</i></span>: Thank you.</p>
<p class="LITERALLAYOUT"> <span class="emphasis"><i
class="EMPHASIS">Client</i></span>: Is there a DHCP server available on the LAN?<br />
<span class="emphasis"><i
class="EMPHASIS">Server</i></span>:Yes, there is. Here I am.<br />
<span class="emphasis"><i
class="EMPHASIS">Client</i></span>:I need an IP address. The last time we<br />
talked, I had 192.168.10.10;<br />
May I have it again?<br />
<span class="emphasis"><i
class="EMPHASIS">Server</i></span>:Yes, you may (or No, you may not: take 192.168.10.12 instead).<br />
<span class="emphasis"><i
class="EMPHASIS">Client</i></span>: Thank you.</p>
<p>The DHCP client in Linux is <tt class="COMMAND">/sbin/dhcpcd</tt>. If you load <tt
class="FILENAME">/etc/rc.d/rc.inet1</tt> in your favorite text editor, you will notice
that <tt class="COMMAND">/sbin/dhcpcd</tt> is called about midway through the script.
This will force the conversation shown above. <tt class="COMMAND">dhcpcd</tt> will also
track the amount of time left on the lease for the current IP address, and will
automatically contact the DHCP server with a request to renew the lease when necessary.
DHCP can also control related information, such as what ntp server to use, what route to
take, etc.</p>
<p>Setting up DHCP on Slackware is simple. Just run <tt class="COMMAND">netconfig</tt>
and select DHCP when offered. If you have more than one NIC and do not wish <tt
class="FILENAME">eth0</tt> to be configured by DHCP, just edit the <tt
class="FILENAME">/etc/rc.d/rc.inet1.conf</tt> file and change the related variable for
your NIC to “<var class="LITERAL">YES</var>”.</p>
</div>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="NETWORK-CONFIGURATION-TCPIP-STATIC"
name="NETWORK-CONFIGURATION-TCPIP-STATIC">5.3.2 Static IP</a></h3>
<p>Static IP addresses are fixed addresses that only change if manually told to. These
are used in any case where an administrator doesn't want the IP information to change,
such for internal servers on a LAN, any server connected to the Internet, and networked
routers. With static IP addressing, you assign an address and leave it at that. Other
machines know that you are always at that certain IP address and can contact you at that
address always.</p>
</div>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="NETWORK-CONFIGURATION-TCPIP-CONF"
name="NETWORK-CONFIGURATION-TCPIP-CONF">5.3.3 <tt
class="FILENAME">/etc/rc.d/rc.inet1.conf</tt></a></h3>
<p>If you plan on assigning an IP address to your new Slackware box, you may do so either
through the <tt class="FILENAME">netconfig</tt> script, or you may edit <tt
class="FILENAME">/etc/rc.d/rc.inet1.conf</tt>. In <tt
class="FILENAME">/etc/rc.d/rc.inet1.conf</tt> , you will notice:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="PROGRAMLISTING">
# Primary network interface card (eth0)
IPADDR[0]=""
NETMASK[0]=""
USE_DHCP[0]=""
DHCP_HOSTNAME[0]=""
</pre>
</td>
</tr>
</table>
<p>Then further at the bottom:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="PROGRAMLISTING">
GATEWAY=""
</pre>
</td>
</tr>
</table>
<p>In this case, our task is merely to place the correct information between the
double-quotes. These variables are called by <tt class="FILENAME">/etc/rc.d/rc.inet1</tt>
at boot time to setup the nics. For each NIC, just enter the correct IP information, or
put “<var class="LITERAL">YES</var>” for <var class="LITERAL">USE_DHCP</var>.
Slackware will startup the interfaces with the information placed here in the order they
are found.</p>
<p>The <var class="LITERAL">DEFAULT_GW</var> variable sets up the default route for
Slackware. All communications between your computer and other computers on the Internet
must pass through that gateway if no other route is specified for them. If you are using
DHCP, you will usually not need to enter anything here, as the DHCP server will specify
what gateway to use.</p>
</div>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="NETWORK-CONFIGURATION-TCPIP-RESOLVER"
name="NETWORK-CONFIGURATION-TCPIP-RESOLVER">5.3.4 <tt
class="FILENAME">/etc/resolv.conf</tt></a></h3>
<p>Ok, so you've got an IP address, you've got a default gateway, you may even have ten
million dollars (give us some), but what good is that if you can't resolve names to IP
addresses? No one wants to type in <tt class="HOSTID">72.9.234.112</tt> into their web
browser to reach <tt class="HOSTID">www.slackbook.org</tt>. After all, who other than the
authors would memorize that IP address? We need to setup DNS, but how? That's where <tt
class="FILENAME">/etc/resolv.conf</tt> comes into play.</p>
<p>Chances are you already have the proper options in <tt
class="FILENAME">/etc/resolv.conf</tt>. If you setup your network connection using DHCP,
the DHCP server should handle updating this file for you. (Technically the DHCP server
just tells <tt class="COMMAND">dhcpcd</tt> what to put here, and it obeys.) If you need
to manually update your DNS server list though, you'll need to hand edit <tt
class="FILENAME">/etc/resolv.conf</tt>. Below is an example:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">#</samp> <kbd class="USERINPUT">cat /etc/resolv.conf</kbd>
nameserver 192.168.1.254
search lizella.net
</pre>
</td>
</tr>
</table>
<p>The first line is simple. The nameserver directive tells us what DNS servers to query.
By necessity these are always IP addresses. You may have as many listed there as you
like. Slackware will happily check one after the other until one returns a match.</p>
<p>The second line is a little more interesting. The search directive gives us a list of
domain names to assume whenever a DNS request is made. This allows you to contact a
machine by only the first part of its FQDN (Fully Qualified Domain Name). For example, if
“slackware.com” were in your search path, you could reach <tt
class="HOSTID">http://store.slackware.com</tt> by just pointing your web browser at <tt
class="HOSTID">http://store</tt>.</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">#</samp> <kbd class="USERINPUT">ping -c 1 store</kbd>
PING store.slackware.com (69.50.233.153): 56 data bytes
64 bytes from 69.50.233.153 : icmp_seq=0 ttl=64 time=0.251 ms
1 packets transmitted, 1 packets received, 0% packet loss
round-trip min/avg/max = 0.251/0.251/0.251 ms
</pre>
</td>
</tr>
</table>
<br />
<br />
</div>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="NETWORK-CONFIGURATION-TCPIP-HOSTS"
name="NETWORK-CONFIGURATION-TCPIP-HOSTS">5.3.5 <tt
class="FILENAME">/etc/hosts</tt></a></h3>
<p>Now that we've got DNS working fine, what if we want to bypass our DNS server, or add
a DNS entry for a machine that isn't in DNS? Slackware includes the oft-loved <tt
class="FILENAME">/etc/hosts</tt> file which contains a local list of DNS names and IP
addresses they should match to.</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">#</samp> <kbd class="USERINPUT">cat /etc/hosts</kbd>
127.0.0.1 localhost locahost.localdomain
192.168.1.101 redtail
172.14.66.32 foobar.slackware.com
</pre>
</td>
</tr>
</table>
<p>Here you can see that localhost has an IP address of <tt class="HOSTID">127.0.0.1</tt>
(always reserved for localhost), redtail can be reached at <tt
class="HOSTID">192.168.1.101</tt>, and <tt class="HOSTID">foobar.slackware.com</tt> is
<tt class="HOSTID">172.14.66.32</tt>.</p>
</div>
</div>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="NETWORK-CONFIGURATION-PPP" name="NETWORK-CONFIGURATION-PPP">5.4
PPP</a></h2>
<p>Many people still connect to the Internet through some kind of dialup connection. The
most common method is PPP, though SLIP is still occasionally used. Setting up your system
to speak PPP to a remote server is pretty easy. We've included a few tools to help you in
setting it up.</p>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="AEN1954" name="AEN1954">5.4.1 <tt
class="COMMAND">pppsetup</tt></a></h3>
<p>Slackware includes a program called <tt class="COMMAND">pppsetup</tt> to configure
your system to use your dialup account. It shares a look and feel similar to our <tt
class="COMMAND">netconfig</tt> program. To run the program, make sure you are logged in
as root. Then type <tt class="COMMAND">pppsetup</tt> to run it. You should see a screen
like this:</p>
<p>The program will present a series of questions, to which you will feed it appropriate
answers. Things like your modem device, the modem initialization string, and the ISP
phone number. Some items will have a default, which you can accept in most cases.</p>
<p>After the program runs, it will create a <tt class="COMMAND">ppp-go</tt> program and a
<tt class="COMMAND">ppp-off</tt> program. These are used to start and stop, respectively,
the PPP connection. The two programs are located in <tt class="FILENAME">/usr/sbin</tt>
and need root privileges to run.</p>
</div>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="AEN1969" name="AEN1969">5.4.2 <tt
class="FILENAME">/etc/ppp</tt></a></h3>
<p>For most users, running <tt class="COMMAND">pppsetup</tt> will be sufficient. However,
there may be an instance where you want to tweak some of the values used by the PPP
daemon. All of the configuration information is kept in <tt
class="FILENAME">/etc/ppp</tt>. Here is a list of what the different files are for:</p>
<div class="INFORMALTABLE"><a id="AEN1975" name="AEN1975"></a>
<table border="0" frame="void" class="CALSTABLE">
<col width="1*" />
<col width="3*" />
<tbody>
<tr>
<td><tt class="COMMAND">ip-down</tt></td>
<td>
<p>This script is run by <tt class="COMMAND">pppd</tt> after the PPP connection is
ended.</p>
</td>
</tr>
<tr>
<td><tt class="COMMAND">ip-up</tt></td>
<td>
<p>This script is run by <tt class="COMMAND">pppd</tt> when there's a successful ppp
connection. Put any commands you want run after a successful connection in this file.</p>
</td>
</tr>
<tr>
<td><tt class="FILENAME">options</tt></td>
<td>
<p>General configuration options for <tt class="COMMAND">pppd</tt>.</p>
</td>
</tr>
<tr>
<td><tt class="FILENAME">options.demand</tt></td>
<td>
<p>General configuration options for <tt class="COMMAND">pppd</tt> when run in demand
dialing mode.</p>
</td>
</tr>
<tr>
<td><tt class="COMMAND">pppscript</tt></td>
<td>
<p>The commands sent to the modem.</p>
</td>
</tr>
<tr>
<td><tt class="FILENAME">pppsetup.txt</tt></td>
<td>
<p>A log of what you entered when you ran <tt class="COMMAND">pppsetup</tt>.</p>
</td>
</tr>
</tbody>
</table>
</div>
<div class="NOTE">
<table class="NOTE" width="100%" border="0">
<tr>
<td width="25" align="CENTER" valign="TOP"><img src="./imagelib/admon/note.png"
hspace="5" alt="Note" /></td>
<td align="LEFT" valign="TOP">
<p>Most of these files won't be there until after you run <tt
class="COMMAND">pppsetup</tt>.</p>
</td>
</tr>
</table>
</div>
</div>
</div>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="NETWORK-CONFIGURATION-WIRELESS"
name="NETWORK-CONFIGURATION-WIRELESS">5.5 Wireless</a></h2>
<p>Wireless networking is still a relatively new thing in the world of computers, yet is
quickly catching on as more people begin to purchase laptops and want networking on the
go, without having to fool with some old twisted pair cable. This trend doesn't appear to
be slowing down. Unfortunately, wireless networking isn't yet as strongly supported in
Linux as traditional wired networking.</p>
<p>There are three basic steps to configuring an 802.11 wireless Ethernet card:</p>
<ol type="1">
<li>
<p>Hardware support for the wireless card</p>
</li>
<li>
<p>Configure the card to connect to a wireless access point</p>
</li>
<li>
<p>Configure the network</p>
</li>
</ol>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="AEN2033" name="AEN2033">5.5.1 Hardware Support</a></h3>
<p>Hardware support for a wireless card is provided through the kernel, either with a
module or built in to the kernel. Generally, most newer Ethernet cards are provided
through kernel modules, so you'll want to determine the appropriate kernel module and
load it through <tt class="FILENAME">/etc/rc.d/rc.modules</tt>. <tt
class="COMMAND">netconfig</tt> may not detect your wireless card, so you'll probably need
to determine the card yourself. See <a
href="http://www.hpl.hp.com/personal/Jean_Tourrilhes/Linux/"
target="_top">http://www.hpl.hp.com/personal/Jean_Tourrilhes/Linux/</a> for more
information on kernel drivers for various wireless cards.</p>
</div>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="AEN2044" name="AEN2044">5.5.2 Configure the Wireless
Settings</a></h3>
<p>The vast majority of this work is done by <tt class="COMMAND">iwconfig</tt>, so as
always read the man page for <tt class="COMMAND">iwconfig</tt> if you need more
information.</p>
<p>First, you'll want to configure your wireless access point. Wireless access points
vary quite a bit in their terminology, and how to configure them, so you may need to
adjust a bit to accommodate your hardware. In general, you'll need at least the following
information:</p>
<ul>
<li>
<p>The domain ID, or name of the network (called the ESSID by <tt
class="COMMAND">iwconfig</tt>)</p>
</li>
<li>
<p>The channel the WAP uses</p>
</li>
<li>
<p>The encryption settings, including any keys used (preferably in hexadecimal)</p>
</li>
</ul>
<div class="WARNING">
<table class="WARNING" width="100%" border="0">
<tr>
<td width="25" align="CENTER" valign="TOP"><img src="./imagelib/admon/warning.png"
hspace="5" alt="Warning" /></td>
<td align="LEFT" valign="TOP">
<p>A NOTE ABOUT WEP. WEP is quit flawed, but it's much better than nothing. If you wish a
greater degree of security on your wireless network, you should investigate VPNs or
IPSec, both of which are beyond the scope of this document. You might also configure your
WAP not to advertise its domain ID/ ESSID. A thorough discussion of wireless policy is
beyond the scope of this section, but a quick Google search will turn up more than you
ever wanted to know.</p>
</td>
</tr>
</table>
</div>
<p>Once you've gathered the above information, and assuming you've used <tt
class="COMMAND">modprobe</tt> to load the appropriate kernel driver, you can edit <tt
class="FILENAME">rc.wireless.conf</tt> and add your settings. The <tt
class="FILENAME">rc.wireless.conf</tt> file is a bit untidy. The least effort is to
modify the generic section with your ESSID and KEY, and CHANNEL if required by your card.
(Try not setting CHANNEL, and if it works, great; if not, set the CHANNEL as
appropriate.) If you're daring, you can modify the file so that only the necessary
variables are set. The variable names in <tt class="FILENAME">rc.wireless.conf</tt>
correspond to the <tt class="COMMAND">iwconfig</tt> parameters, and are read by <tt
class="FILENAME">rc.wireless</tt> and used in the appropriate <tt
class="COMMAND">iwconfig</tt> commands.</p>
<p>If you have your key in hexadecimal, that's ideal, since you can be fairly confident
that your WAP and <tt class="COMMAND">iwconfig</tt> will agree on the key. If you only
have a string, you can't be sure how your WAP will translate that into a hexadecimal key,
so some guesswork may be needed (or get your WAP's key in hex).</p>
<p>Once you've modified <tt class="FILENAME">rc.wireless.conf</tt>, run <tt
class="FILENAME">rc.wireless</tt> as <tt class="USERNAME">root</tt>, then run <tt
class="FILENAME">rc.inet1</tt>, again as <tt class="USERNAME">root</tt>. You can test
your wireless networking with standard testing tools such as <tt
class="COMMAND">ping</tt>, along with <tt class="COMMAND">iwconfig</tt>. If you have a
wired interface you may wish to use <tt class="COMMAND">ifconfig</tt> to turn those
interfaces off while you test your wireless networking to ensure there's no interference.
You may also want to test your changes through a reboot.</p>
<p>Now that you've seen how to edit <tt class="FILENAME">/etc/rc.d/rc.wireless</tt> for
you default network, let's take a closer look at iwconfig and see how it all works. This
will teach you the quick and dirty way of setting up wifi for those times when you find
yourself at an Internet cafe, coffee shop, or any other wifi hot spot and wish to get
online.</p>
<p>The first step is to tell your wireless NIC what network to join. Make sure you
replace “<tt class="FILENAME">eth0</tt>” with whatever network interface your
wireless card uses and change “<var class="REPLACEABLE">mynetwork</var>” to
the essid you wish to use. Yes, we know you're smarter than that. Next you'll have to
specify the encryption key (if any) used on your wireless network. Finally specify the
channel to use (if needed).</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">#</samp> <kbd class="USERINPUT">iwconfig eth0 essid "<var
class="REPLACEABLE">mynetwork</var>"</kbd>
<samp class="PROMPT">#</samp> <kbd class="USERINPUT">iwconfig eth0 key <var
class="REPLACEABLE">XXXXXXXXXXXXXXXXXXXXXXXXXXX</var></kbd>
<samp class="PROMPT">#</samp> <kbd class="USERINPUT">iwconfig eth0 channel n</kbd>
</pre>
</td>
</tr>
</table>
<p>That should be all on the wireless end of things.</p>
</div>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="AEN2101" name="AEN2101">5.5.3 Configure the Network</a></h3>
<p>This is done in the exact same way as wired networks. Simply refer to earlier sections
of this chapter.</p>
</div>
</div>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="NETWORK-CONFIGURATION-NFS" name="NETWORK-CONFIGURATION-NFS">5.6
Network File Systems</a></h2>
<p>At this point, you should have a working TCP/IP connection to your network. You should
be able to ping other computers on your internal network and, if you have configured an
appropriate gateway, you should also be able to ping computers on the Internet itself. As
we know, the whole point in bringing a computer onto a network is to access information.
While some people might bring a computer up on a network just for the fun of it, most
people wish to be able to share files and printers. They wish to be able to access
documents on the Internet or play an online game. Having TCP/IP installed and functional
on your new Slackware system is a means to that end, but with just TCP/IP installed,
functionality will be very rudimentary. To share files, we will have to transfer them
back and forth using either FTP or SCP. We cannot browse files on our new Slackware
computer from the Network Neighborhood or My Network Places icons on Windows computers.
We'd like to be able to access files on other Unix machines seamlessly.</p>
<p>Ideally, we'd like to be able to use a <span class="emphasis"><i
class="EMPHASIS">network file system</i></span> to allow us transparent access to our
files on other computers. The programs that we use to interact with information stored on
our computers really do not need to know on what computer a given file is stored; they
just need to know that it exists and how to get to it. It is then the responsibility of
the operating system to manage access to that file through the available file systems and
network file systems. The two most commonly used network file systems are SMB (as
implemented by Samba) and NFS.</p>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="NETWORK-CONFIGURATION-NSF-SMB"
name="NETWORK-CONFIGURATION-NSF-SMB">5.6.1 SMB/Samba/CIFS</a></h3>
<p>SMB (for Server Message Block) is a descendant of the older NetBIOS protocol that was
initially used by IBM in their LAN Manager product. Microsoft has always been fairly
interested in NetBIOS and it's successors (NetBEUI, SMB and CIFS). The Samba project has
existed since 1991, when it was originally written to link an IBM PC running NetBIOS with
a Unix server. These days, SMB is the preferred method for sharing file and print
services over a network for virtually the entire civilized world because Windows supports
it.</p>
<p>Samba's configuration file is <tt class="FILENAME">/etc/samba/smb.conf</tt>; one of
the most well commented and documented configuration files you will find anywhere. Sample
shares have been setup for you to view and modify for your needs. If you need even
tighter control the man page for smb.conf is indispensable. Since Samba is documented so
well in the places I've mentioned above, we will not rewrite the documentation here. We
will, however, quickly cover the basics.</p>
<p><tt class="FILENAME">smb.conf</tt> is broken down into multiple sections: one section
per share, and a global section for setting options that are to be used everywhere. Some
options are only valid in the global section; some are only valid outside the global
section. Remember that the global section can be over-ridden by any other section. Refer
to the man pages for more information.</p>
<p>You will most likely wish to edit your <tt class="FILENAME">smb.conf</tt> file to
reflect the network settings in your LAN. I would suggest modifying the items listed
below:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="PROGRAMLISTING">
[global]
# workgroup = NT-Domain-Name or Workgroup-Name, eg: LINUX2
workgroup = MYGROUP
</pre>
</td>
</tr>
</table>
<p>Change the workgroup name to reflect the workgroup or domain name that you are using
locally.</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="PROGRAMLISTING">
# server string is the equivalent of the NT Description field
server string = Samba Server
</pre>
</td>
</tr>
</table>
<p>This will be the name of your Slackware computer displayed in the Network Neighborhood
(or My Network Places) folder.</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="PROGRAMLISTING">
# Security mode. Most people will want user level security. See
# security_level.txt for details. NOTE: To get the behaviour of
# Samba-1.9.18, you'll need to use "security = share".
security = user
</pre>
</td>
</tr>
</table>
<p>You'll almost certainly wish to implement user level security on your Slackware
system.</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="PROGRAMLISTING">
# You may wish to use password encryption. Please read
# ENCRYPTION.txt, Win95.txt and WinNT.txt in the Samba
# documentation.
# Do not enable this option unless you have read those documents
encrypt passwords = yes
</pre>
</td>
</tr>
</table>
<p>If encrypt passwords is not enabled, you will not be able to use Samba with NT4.0,
Win2k, WinXP, and Win2003. Earlier Windows operating systems did not require encryption
to share files.</p>
<p>SMB is an authenticated protocol, meaning you must supply a correct username and
password in order to use this service. We tell the samba server what usernames and
passwords are valid with the <tt class="COMMAND">smbpasswd</tt> command. <tt
class="COMMAND">smbpasswd</tt> takes a couple of common switches to tell it to either add
traditional users, or add machine users (SMB requires that you add the computers' NETBIOS
names as machine users, restricting what computers one can authenticate from).</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
Adding a user to the <tt class="FILENAME">/etc/samba/private/smbpasswd</tt> file.
<samp class="PROMPT">#</samp> <kbd class="USERINPUT">smbpasswd -a user</kbd>
Adding a machine name to the /etc/samba/private/smbpasswd file.
<samp class="PROMPT">#</samp> <kbd class="USERINPUT">smbpasswd -a -m machine</kbd>
</pre>
</td>
</tr>
</table>
<p>It's important to note that a given username or machine name must already exist in the
<tt class="FILENAME">/etc/passwd</tt> file. You can accomplish this simply with the <tt
class="COMMAND">adduser</tt> command. Note that when using the <tt
class="COMMAND">adduser</tt> command to add a machine name one must append a dollar sign
(“<var class="LITERAL">$</var>”) to the machine name. This should <span
class="emphasis"><i class="EMPHASIS">not</i></span> however, be done with <tt
class="COMMAND">smbpasswd</tt>. <tt class="COMMAND">smbpasswd</tt> appends the dollar
sign on its own. Failing to mangle the machine name this way with <tt
class="COMMAND">adduser</tt> will result in an error when adding the machine name to
samba.</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">#</samp> <kbd class="USERINPUT">adduser machine$</kbd>
</pre>
</td>
</tr>
</table>
</div>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="NETWORK-CONFIGURATION-NFS-NFS"
name="NETWORK-CONFIGURATION-NFS-NFS">5.6.2 Network File System (NFS)</a></h3>
<p>NFS (or Network File System) was originally written by Sun for their Solaris
implementation of Unix. While it is significantly easier to get up and running when
compared to SMB, it is also significantly less secure. The primary insecurity in NFS is
that it is easy to spoof user and group id's from one machine to another. NFS is an
unauthenticated protocol. Future versions of the NFS protocol are being devised that
enhance security, but these are not common at the time of this writing.</p>
<p>NFS configuration is governed by the <tt class="FILENAME">/etc/exports</tt> file. When
you load the default <tt class="FILENAME">/etc/exports</tt> file into an editor, you'll
see a blank file with a two line comment on top. We'll need to add a line to the exports
file for each directory that we wish to export, with a listing of client workstations
that will be allowed to access that file. For instance, if we wished to export directory
<tt class="FILENAME">/home/foo</tt> to workstation Bar, we would simply add the line:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="PROGRAMLISTING">
/home/foo Bar(rw)
</pre>
</td>
</tr>
</table>
<p>to our <tt class="FILENAME">/etc/exports</tt>. Below, you'll find the example from the
man page for the <tt class="FILENAME">exports</tt> file:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="PROGRAMLISTING">
# sample /etc/exports file
/ master(rw) trusty(rw,no_root_squash)
/projects proj*.local.domain(rw)
/usr *.local.domain(ro) @trusted(rw)
/home/joe pc001(rw,all_squash,anonuid=150,anongid=100)
/pub (ro,insecure,all_squash)
</pre>
</td>
</tr>
</table>
<p>As you can see, there are various options available, but most should be fairly clear
from this example.</p>
<p>NFS works under the assumption that a given user on one machine in a network has the
same user ID on all machines across the network. When an attempt is made to read or write
from a NFS client to an NFS server, a UID is passed as part of the read/write request.
This UID is treated the same as if the read/write request originated on the local
machine. As you can see, if one could arbitrarily specify a given UID when accessing
resources on a remote system, Bad Things (tm) could and would happen. As a partial hedge
against this, each directory is mounted with the <var class="OPTION">root_squash</var>
option. This maps the UID for any user claiming to be root to a different UID, thus
preventing root access to the files or folders in the exported directory. <var
class="OPTION">root_squash</var> seems to be enabled by default as a security measure,
but the authors recommend specifying it anyway in your <tt
class="FILENAME">/etc/exports</tt> file.</p>
<p>You can also export a directory directly from the command line on the server by using
the <tt class="COMMAND">exportfs</tt> command as follows:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">#</samp> <kbd
class="USERINPUT">exportfs -o rw,no_root_squash Bar:/home/foo</kbd>
</pre>
</td>
</tr>
</table>
<p>This line exports the <tt class="FILENAME">/home/foo</tt> directory to the computer
“<tt class="HOSTID">Bar</tt>” and grants <tt class="HOSTID">Bar</tt>
read/write access. Additionally, the NFS server will not invoke <var
class="OPTION">root_squash</var>, which means any user on Bar with a UID of
“0” (root's UID) will have the same privileges as root on the server. The
syntax does look strange (usually when a directory is specified in <var
class="LITERAL">computer:/directory/file</var> syntax, you are referring to a file in a
directory on a given computer).</p>
<p>You'll find more information on the man page for the exports file.</p>
</div>
</div>
</div>
<div class="CHAPTER">
<hr />
<h1><a id="X-WINDOW-SYSTEM" name="X-WINDOW-SYSTEM"></a>Chapter 6 X Configuration</h1>
<p>Starting with Slackware-10.0, the X Window environment in Slackware is provided by
Xorg. X is responsible for providing a graphical user interface. It is independent from
the operating system, unlike Windows or the MacOS.</p>
<p>The X Window System is implemented through many programs that run in userland. The two
main components are the server and the window manager. The server provides the lowlevel
functions for interacting with your video hardware, thus it is system specific. The
window manager sits on top of the server and provides the user interface. The advantage
to this is you can have many different graphical interfaces by simply changing the window
manager you use.</p>
<p>Configuring X can be a complex task. The reason for this is the vast numbers of video
cards available for the PC architecture, most of which use different programming
interfaces. Luckily, most cards today support basic video standards known as VESA, and if
your card is among them you'll be able to start X using the <tt
class="COMMAND">startx</tt> command right out of the box.</p>
<p>If this doesn't work with your card, or if you'd like to take advantage of the
high-performance features of your video card such as hardware acceleration or 3-D
hardware rendering, then you'll need to reconfigure X.</p>
<p>To configure X, you'll need to make an <tt class="FILENAME">/etc/X11/xorg.conf</tt>
file. This file contains lots of details about your video hardware, mouse, and monitor.
It's a very complex configuration file, but fortunately there are several programs to
help create one for you. We'll mention a few of them here.</p>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="X-WINDOW-SYSTEM-XORGCONFIG"
name="X-WINDOW-SYSTEM-XORGCONFIG">6.1 <tt class="COMMAND">xorgconfig</tt></a></h2>
<p>This is a simple menu driven frontend that's similar in feel to the Slackware
installer. It simply tells the X server to take a look at the card, and then set up the
best initial configuration file it can make based on the information it gathers. The
generated <tt class="FILENAME">/etc/X11/xorg.conf</tt> file should be a good starting
point for most systems (and should work without modification).</p>
<p>This is a text-based X configuration program that's designed for the advanced system
administrator. Here's a sample walkthrough using <tt class="COMMAND">xorgconfig</tt>.
First, start the program:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">#</samp> <kbd class="USERINPUT">xorgconfig</kbd>
</pre>
</td>
</tr>
</table>
<p>This will present a screenful of information about <tt
class="COMMAND">xorgconfig</tt>. To continue, press <kbd class="USERINPUT">ENTER</kbd>.
<tt class="COMMAND">xorgconfig</tt> will ask you to verify you have set your <tt
class="ENVAR">PATH</tt> correctly. It should be fine, so go ahead and hit <kbd
class="USERINPUT">ENTER</kbd>.</p>
<div class="FIGURE"><a id="X-WINDOW-SYSTEM-1" name="X-WINDOW-SYSTEM-1"></a>
<p><b>Figure 6-1. <tt class="COMMAND">xorgconfig</tt> Mouse Configuration</b></p>
<p><img src="x-window-system/xorgconfig1-w.png" /></p>
</div>
<p>Select your mouse from the menu presented. If you don't see your serial mouse listed,
pick the Microsoft protocol -- it's the most common and will probably work. Next <tt
class="COMMAND">xorgconfig</tt> will ask you about using <var
class="OPTION">ChordMiddle</var> and <var class="OPTION">Emulate3Buttons</var>. You'll
see these options described in detail on the screen. Use them if the middle button on
your mouse doesn't work under X, or if your mouse only has two buttons (<var
class="OPTION">Emulate3Buttons</var> lets you simulate the middle button by pressing both
buttons simultaneously). Then, enter the name of your mouse device. The default choice,
<tt class="FILENAME">/dev/mouse</tt>, should work since the link was configured during
Slackware setup. If you're running GPM (the Linux mouse server) in repeater mode, you can
set your mouse type to <tt class="FILENAME">/dev/gpmdata</tt> to have X get information
about the mouse through <tt class="COMMAND">gpm</tt>. In some cases (with busmice
especially) this can work better, but most users shouldn't do this.</p>
<p><tt class="COMMAND">xorgconfig</tt> will ask you about enabling special key bindings.
If you need this say “<kbd class="USERINPUT">y</kbd>”. Most users can say
“<kbd class="USERINPUT">n</kbd>” -- enter this if you're not sure.</p>
<div class="FIGURE"><a id="X-WINDOW-SYSTEM-2" name="X-WINDOW-SYSTEM-2"></a>
<p><b>Figure 6-2. <tt class="COMMAND">xorgconfig</tt> Horizontal Sync</b></p>
<p><img src="x-window-system/xorgconfig2-w.png" /></p>
</div>
<p>In the next section you enter the sync range for your monitor. To start configuring
your monitor, press <kbd class="USERINPUT">ENTER</kbd>. You will see a list of monitor
types -- choose one of them. Be careful not to exceed the specifications of your monitor.
Doing so could damage your hardware.</p>
<div class="FIGURE"><a id="X-WINDOW-SYSTEM-3" name="X-WINDOW-SYSTEM-3"></a>
<p><b>Figure 6-3. <tt class="COMMAND">xorgconfig</tt> Vertical Sync</b></p>
<p><img src="x-window-system/xorgconfig3-w.png" /></p>
</div>
<p>Specify the vertical sync range for your monitor (you should find this in the manual
for the monitor). xorgconfig will ask you to enter strings to identify the monitor type
in the <tt class="FILENAME">xorg.conf</tt> file. Enter anything you like on these 3 lines
(including nothing at all).</p>
<div class="FIGURE"><a id="X-WINDOW-SYSTEM-4" name="X-WINDOW-SYSTEM-4"></a>
<p><b>Figure 6-4. <tt class="COMMAND">xorgconfig</tt> Video Card</b></p>
<p><img src="x-window-system/xorgconfig4-w.png" /></p>
</div>
<p>Now you have the opportunity to look at the database of video card types. You'll want
to do this, so say “<kbd class="USERINPUT">y</kbd>”, and select a card from
the list shown. If you don't see your exact card, try selecting one that uses the same
chipset and it will probably work fine.</p>
<p>Next, tell <tt class="COMMAND">xorgconfig</tt> how much RAM you have on your video
card. <tt class="COMMAND">xorgconfig</tt> will want you to enter some more descriptive
text about your video card. If you like, you can enter descriptions on these three
lines.</p>
<p>You'll then be asked which display resolutions you want to use. Again, going with the
provided defaults should be fine to start with. Later on, you can edit the <tt
class="FILENAME">/etc/X11/xorg.conf</tt> file and rearrange the modes so 1024x768 (or
whatever mode you like) is the default.</p>
<p>At this point, the <tt class="COMMAND">xorgconfig</tt> program will ask if you'd like
to save the current configuration file. Answer yes, and the X configuration file is
saved, completing the setup process. You can start X now with the <tt
class="COMMAND">startx</tt> command.</p>
</div>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="X-WINDOW-SYSTEM-XORGSETUP" name="X-WINDOW-SYSTEM-XORGSETUP">6.2
<tt class="COMMAND">xorgsetup</tt></a></h2>
<p>The second way to configure X is to use <tt class="COMMAND">xorgsetup</tt>, an
automagical configuration program that comes with Slackware.</p>
<p>To run <tt class="COMMAND">xorgsetup</tt>, log in as root and type:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">#</samp> <kbd class="USERINPUT">xorgsetup</kbd>
</pre>
</td>
</tr>
</table>
<p>If you've already got an <tt class="FILENAME">/etc/X11/xorg.conf</tt> file (because
you've already configured X), you'll be asked if you want to backup the existing config
file before continuing. The original file will be renamed to <tt
class="FILENAME">/etc/X11/xorg.conf.backup</tt>.</p>
</div>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="X-WINDOW-SYSTEM-XINITRC" name="X-WINDOW-SYSTEM-XINITRC">6.3
xinitrc</a></h2>
<p><tt class="COMMAND">xinit</tt>(1) is the program that actually starts X; it is called
by <tt class="COMMAND">startx</tt>(1), so you may not have noticed it (and probably don't
really need to). Its configuration file, however, determines which programs (including
and especially the window manager) are run when X starts up. <tt
class="COMMAND">xinit</tt> first checks your home directory for a <tt
class="FILENAME">.xinitrc</tt> file. If the file is found, it gets run; otherwise, <tt
class="FILENAME">/var/X11R6/lib/xinit/xinitrc</tt> (the systemwide default) is used.
Here's a simple <tt class="FILENAME">xinitrc</tt> file:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="PROGRAMLISTING">
#!/bin/sh
# $XConsortium: xinitrc.cpp,v 1.4 91/08/22 11:41:34 rws Exp $
userresources=$HOME/.Xresources
usermodmap=$HOME/.Xmodmap
sysresources=/usr/X11R6/lib/X11/xinit/.Xresources
sysmodmap=/usr/X11R6/lib/X11/xinit/.Xmodmap
# merge in defaults and keymaps
if [ -f $sysresources ]; then
xrdb -merge $sysresources
fi
if [ -f $sysmodmap ]; then
xmodmap $sysmodmap
fi
if [ -f $userresources ]; then
xrdb -merge $userresources
fi
if [ -f $usermodmap ]; then
xmodmap $usermodmap
fi
# start some nice programs
twm &
xclock -geometry 50x50-1+1 &
xterm -geometry 80x50+494+51 &
xterm -geometry 80x20+494-0 &
exec xterm -geometry 80x66+0+0 -name login
</pre>
</td>
</tr>
</table>
<p>All of those “if” blocks are there to merge in various configuration
settings from other files. The interesting part of the file is toward the end, where
various programs are run. This X session will begin with the <tt
class="COMMAND">twm</tt>(1) window manager, a clock, and three terminals. Note the <tt
class="COMMAND">exec</tt> before the last <tt class="COMMAND">xterm</tt>. What that does
is replace the currently running shell (the one that's executing this <tt
class="FILENAME">xinitrc</tt> script) with that <tt class="COMMAND">xterm</tt>(1)
command. When the user quits that <tt class="COMMAND">xterm</tt>, the X session will
end.</p>
<p>To customize your X startup, copy the default <tt
class="FILENAME">/var/X11R6/lib/xinit/xinitrc</tt> to <tt
class="FILENAME">~/.xinitrc</tt> and edit it, replacing those program lines with whatever
you like. The end of mine is simply:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="PROGRAMLISTING">
# Start the window manager:
exec startkde
</pre>
</td>
</tr>
</table>
<p>Note that there are several <tt class="FILENAME">xinitrc.*</tt> files in <tt
class="FILENAME">/var/X11R6/lib/xinit</tt> that correspond to various window managers and
GUIs. You can use any of those, if you like.</p>
</div>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="X-WINDOW-SYSTEM-XWMCONFIG" name="X-WINDOW-SYSTEM-XWMCONFIG">6.4
<tt class="COMMAND">xwmconfig</tt></a></h2>
<p>For years, Unix was used almost exclusively as the operating system for servers, with
the exception of high-powered professional workstations. Only the technically inclined
were likely to use a Unix-like operating system, and the user interface reflected this
fact. GUIs tended to be fairly bare-bones, designed to run a few necessarily graphical
applications like CAD programs and image renderers. Most file and system management was
conducted at the command line. Various vendors (Sun Microsystems, Silicon Graphics, etc)
were selling workstations with an attempt to provide a cohesive “look and
feel”, but the wide variety of GUI toolkits in use by developers led inevitably to
the dissolution of the desktop's uniformity. A scrollbar might not look the same in two
different applications. Menus might appear in different places. Programs would have
different buttons and checkboxes. Colors ranged widely, and were generally hard-coded in
each toolkit. As long as the users were primarily technical professionals, none of this
mattered much.</p>
<p>With the advent of free Unix-like operating systems and the growing number and variety
of graphical applications, X has recently gained a wide desktop user base. Most users, of
course, are accustomed to the consistent look and feel provided by Microsoft's Windows or
Apple's MacOS; the lack of such consistency in X-based applications became a barrier to
its wider acceptance. In response, two open source projects have been undertaken: The K
Desktop Environment, or KDE, and the GNU Network Object Model Environment, known as
GNOME. Each has a wide variety of applications, from taskbars and file managers to games
and office suites, written with the same GUI toolkit and tightly integrated to provide a
uniform, consistent desktop.</p>
<p>The differences in KDE and GNOME are generally fairly subtle. They each look different
from the other, because each uses a different GUI toolkit. KDE is based on the Qt library
from Troll Tech AS, while GNOME uses GTK, a toolkit originally developed for The GNU
Image Manipulation Program (or The GIMP, for short). As separate projects, KDE and GNOME
each have their own designers and programmers, with different development styles and
philosophies. The result in each case, however, has been fundamentally the same: a
consistent, tightly integrated desktop environment and application collection. The
functionality, usability, and sheer prettiness of both KDE and GNOME rival anything
available on other operating systems.</p>
<p>The best part, though, is that these advanced desktops are free. This means you can
have either or both (yes, at the same time). The choice is yours.</p>
<p>In addition to the GNOME and KDE desktops, Slackware includes a large collection of
window managers. Some are designed to emulate other operating systems, some for
customization, others for speed. There's quite a variety. Of course you can install as
many as you want, play with them all, and decide which you like the most.</p>
<p>To make desktop selection easy, Slackware also includes a program called <tt
class="COMMAND">xwmconfig</tt> that can be used to select a desktop or window manager. It
is run like so:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">xwmconfig</kbd>
</pre>
</td>
</tr>
</table>
<div class="FIGURE"><a id="FIG-X-WINDOW-SYSTEM-XWMCONFIG"
name="FIG-X-WINDOW-SYSTEM-XWMCONFIG"></a>
<p><b>Figure 6-5. Desktop Configuration with <tt class="COMMAND">xorgconfig</tt></b></p>
<p><img src="x-window-system/xwmconfig-w.png" /></p>
</div>
<p>You'll be given a list of all the desktops and window managers installed. Just select
the one you want from the list. Each user on your system will need to run this program,
since different users can use different desktops, and not everyone will want the default
one you selected at installation.</p>
<p>Then just start up X, and you're good to go.</p>
</div>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="X-WINDOW-SYSTEM-XDM" name="X-WINDOW-SYSTEM-XDM">6.5 <tt
class="COMMAND">xdm</tt></a></h2>
<p>As Linux becomes more and more useful as a desktop operating system, many users find
it desirable for the machine to boot straight into a graphical environment. For this, you
will need to tell Slackware to boot straight into X, and assign a graphical login
manager. Slackware ships with three graphical login tools, <tt
class="COMMAND">xdm</tt>(1), <tt class="COMMAND">kdm</tt>, and <tt
class="COMMAND">gdm</tt>(1).</p>
<p><tt class="COMMAND">xdm</tt> is the graphical login manager shipped with the X.org
system. It's ubiquitous, but not as fully features as alternatives. <tt
class="COMMAND">kdm</tt> is the graphical login manager shipped with KDE, The K Desktop
Environment. Finally, <tt class="COMMAND">gdm</tt> is the login manager shipped with
GNOME. Any of the choices will allow you to log in as any user, and choose what desktop
you wish to use.</p>
<p>Unfortunately, Slackware doesn't include a nice program like <tt
class="COMMAND">xwmconfig</tt> for choosing what login manager to use, so if all three
are installed you may have to do some editing to choose your preference. But first, we'll
discuss how to boot into a graphical environment.</p>
<p>In order to start X at boot, you need to boot into run-level 4. Run-levels are just a
way of telling <tt class="COMMAND">init</tt>(8) to do something different when it starts
the OS. We do this by editing the config file for <tt class="COMMAND">init</tt>, <tt
class="FILENAME">/etc/inittab</tt>.</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="PROGRAMLISTING">
# These are the default runlevels in Slackware:
# 0 = halt
# 1 = single user mode
# 2 = unused (but configured the same as runlevel 3)
# 3 = multiuser mode (default Slackware runlevel)
# 4 = X11 with KDM/GDM/XDM (session managers)
# 5 = unused (but configured the same as runlevel 3)
# 6 = reboot
# Default runlevel. (Do not set to 0 or 6)
id:3:initdefault:
</pre>
</td>
</tr>
</table>
<p>In order to make Slackware boot to a graphical environment, we just change the 3 to a
4.</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="PROGRAMLISTING">
# Default runlevel. (Do not set to 0 or 6)
id:4:initdefault:
</pre>
</td>
</tr>
</table>
<p>Now Slackware will boot into runlevel 4 and execute <tt
class="FILENAME">/etc/rc.d/rc.4</tt>. This file starts up X and calls whatever login
manager you've chosen. So, how do we choose login managers? There are a few ways to do
this, and I'll explain them after we look at <tt class="FILENAME">rc.4</tt>.</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="PROGRAMLISTING">
# Try to use GNOME's gdm session manager:
if [ -x /usr/bin/gdm ]; then
exec /usr/bin/gdm -nodaemon
fi
# Not there? OK, try to use KDE's kdm session manager:
if [ -x /opt/kde/bin/kdm ]; then
exec /opt/kde/bin/kdm -nodaemon
fi
# If all you have is XDM, I guess it will have to do:
if [ -x /usr/X11R6/bin/xdm ]; then
exec /usr/X11R6/bin/xdm -nodaemon
fi
</pre>
</td>
</tr>
</table>
<p>As you can see here, <tt class="FILENAME">rc.4</tt> first checks to see if <tt
class="COMMAND">gdm</tt> is executable, and if so runs it. Second on the list is <tt
class="COMMAND">kdm</tt>, and finally <tt class="COMMAND">xdm</tt>. One way of choosing a
login manager is to simply remove the ones you don't wish to use using <tt
class="COMMAND">removepkg</tt>. You can find out more about <tt
class="COMMAND">removepkg</tt> in <a href="#PACKAGE-MANAGEMENT">Chapter 18</a>.</p>
<p>Optionally, you can remove the executable permission from those files that you don't
want to use. We discuss <tt class="COMMAND">chmod</tt> in <a
href="#FILESYSTEM-STRUCTURE">Chapter 9</a>.</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">#</samp> <kbd class="USERINPUT">chmod -x /usr/bin/gdm</kbd>
</pre>
</td>
</tr>
</table>
<p>Finally, you can just comment out the lines for the login manager you don't want to
use.</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="PROGRAMLISTING">
# Try to use GNOME's gdm session manager:
# if [ -x /usr/bin/gdm ]; then
# exec /usr/bin/gdm -nodaemon
# fi
# Not there? OK, try to use KDE's kdm session manager:
if [ -x /opt/kde/bin/kdm ]; then
exec /opt/kde/bin/kdm -nodaemon
fi
# If all you have is XDM, I guess it will have to do:
if [ -x /usr/X11R6/bin/xdm ]; then
exec /usr/X11R6/bin/xdm -nodaemon
fi
</pre>
</td>
</tr>
</table>
<p>Any lines preceded by the hash mark (<var class="LITERAL">#</var>) are considered
comments and the shell silently passes them. Thus, even if <tt class="COMMAND">gdm</tt>
is installed and executable, the shell (in this case <tt class="COMMAND">bash</tt>) won't
bother checking for it.</p>
</div>
</div>
<div class="CHAPTER">
<hr />
<h1><a id="BOOTING" name="BOOTING"></a>Chapter 7 Booting</h1>
<p>The process of booting your Linux system can sometimes be easy and sometimes be
difficult. Many users install Slackware on their computer and that's it. They just turn
it on and it's ready to use. Othertimes, simply booting the machine can be a chore. For
most users, LILO works best. Slackware includes LILO and Loadlin for booting Slackware
Linux. LILO will work from a hard drive partition, a hard drive's master boot record, or
a floppy disk, making it a very versatile tool. Loadlin works from a DOS command line,
killing DOS and invoking Linux.</p>
<p>Another popular utility for booting Linux is GRUB. GRUB is not included or officially
supported by Slackware. Slackware holds to the “tried and true” standard for
what gets included inside the distribution. While GRUB works well and includes some
features that LILO does not, LILO handles all the essential tasks of a boot loader
reliably with a proven track record. Being younger, GRUB hasn't quite lived up to that
legacy yet. As it is not included with Slackware, we do not discuss it here. If you wish
to use GRUB (perhaps it came with another Linux OS and you want to use it to dual-boot)
consult GRUB's documentation.</p>
<p>This section covers using LILO and Loadlin, the two booters included with Slackware.
It also explains some typical dual booting scenarios and how you could go about setting
it up.</p>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="BOOTING-LILO" name="BOOTING-LILO">7.1 LILO</a></h2>
<p>The Linux Loader, or LILO, is the most popular booter in use on Linux systems. It is
quite configurable and can easily be used to boot other operating systems.</p>
<p>Slackware Linux comes with a menu-driven configuration utility called <tt
class="COMMAND">liloconfig</tt>. This program is first run during the setup process, but
you can invoke it later by typing <tt class="COMMAND">liloconfig</tt> at the prompt.</p>
<p>LILO reads its settings from the <tt class="COMMAND">/etc/lilo.conf</tt>(5) file. It
is not read each time you boot up, but instead is read each time you install LILO. LILO
must be reinstalled to the boot sector each time you make a configuration change. Many
LILO errors come from making changes to the <tt class="FILENAME">lilo.conf</tt> file, but
failing to re-run lilo to install these changes. <tt class="COMMAND">liloconfig</tt> will
help you build the configuration file so that you can install LILO for your system. If
you prefer to edit <tt class="FILENAME">/etc/lilo.conf</tt> by hand, then reinstalling
LILO just involves typing <tt class="COMMAND">/sbin/lilo</tt> (as <tt
class="USERNAME">root</tt>) at the prompt.</p>
<p>When you first invoke <tt class="COMMAND">liloconfig</tt>, it will look like this:</p>
<div class="FIGURE"><a id="BOOTING-SETUP-LILO" name="BOOTING-SETUP-LILO"></a>
<p><b>Figure 7-1. <tt class="COMMAND">liloconfig</tt></b></p>
<p><img src="booting/setup-lilo-w.png" /></p>
</div>
<p>If this is your first time setting up LILO, you should pick simple. Otherwise, you
might find expert to be faster if you are familiar with LILO and Linux. Selecting simple
will begin the LILO configuration.</p>
<p>If kernel frame buffer support is compiled into your kernel, <tt
class="COMMAND">liloconfig</tt> will ask which video resolution you would like to use.
This is the resolution that is also used by the XFree86 frame buffer server. If you do
not want the console to run in a special video mode, selecting normal will keep the
standard 80x25 text mode in use.</p>
<p>The next part of the LILO configuration is selecting where you want it installed. This
is probably the most important step. The list below explains the installation places:</p>
<div class="VARIABLELIST">
<dl>
<dt><var class="OPTION">Root</var></dt>
<dd>
<p>This option installs LILO to the beginning of your Linux root partition. This is the
safest option if you have other operating systems on your computer. It ensures that any
other booters are not overwritten. The disadvantage is that LILO will only load from here
if your Linux drive is the first drive on your system. This is why many people chose to
create a very small <tt class="FILENAME">/boot</tt> partition as the first drive on their
system. This allows the kernel and LILO to be installed at the beginning of the drive
where LILO can find them. Previous versions of LILO contained an infamous flaw known as
the “1024 cylinder limit”. LILO was unable to boot kernels on partitions past
the 1024th cylinder. Recent editions of LILO have eliminated this problem.</p>
</dd>
<dt><var class="OPTION">Floppy</var></dt>
<dd>
<p>This method is even safer than the previous one. It creates a boot floppy that you can
use to boot your Linux system. This keeps the booter off the hard disk entirely, so you
only boot this floppy when you want to use Slackware. The flaws with this method are
obvious. Floppies are notoriously fickle, prone to failures. Secondly, the boot loader is
no longer self-contained within the computer. If you loose your floppy disk, you'll have
to make another to boot your system.</p>
</dd>
<dt><var class="OPTION">MBR</var></dt>
<dd>
<p>You will want to use this method if Slackware is the only operating system on your
computer, or if you will be using LILO to choose between multiple operating systems on
your computer. This is the most preferred method for installing LILO and will work with
almost any computer system.</p>
<div class="WARNING">
<table class="WARNING" width="90%" border="0">
<tr>
<td width="25" align="CENTER" valign="TOP"><img src="./imagelib/admon/warning.png"
hspace="5" alt="Warning" /></td>
<td align="LEFT" valign="TOP">
<p>This option will overwrite any other booter you have in the MBR.</p>
</td>
</tr>
</table>
</div>
</dd>
</dl>
</div>
<p>After selecting the installation location, <tt class="COMMAND">liloconfig</tt> will
write the configuration file and install LILO. That's it. If you select the expert mode
you will receive a special menu. This menu allows you to tweak the <tt
class="FILENAME">/etc/lilo.conf</tt> file, add other operating systems to your boot menu,
and set LILO to pass special kernel parameters at boot time. The expert menu looks like
this:</p>
<div class="FIGURE"><a id="BOOTING-LILO-EXPERT" name="BOOTING-LILO-EXPERT"></a>
<p><b>Figure 7-2. <tt class="COMMAND">liloconfig</tt> Expert Menu</b></p>
<p><img src="booting/setup-lilo-expert-w.png" /></p>
</div>
<p>Whatever your system configuration is, setting up a working boot loader is easy. <tt
class="COMMAND">liloconfig</tt> makes setting it up a cinch.</p>
</div>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="BOOTING-LOADLIN" name="BOOTING-LOADLIN">7.2 LOADLIN</a></h2>
<p>The other booting option that comes with Slackware Linux is LOADLIN. LOADLIN is a DOS
executable that can be used to start Linux from a running DOS system. It requires the
Linux kernel to be on the DOS partition so that LOADLIN can load it and properly boot the
system.</p>
<p>During the installation process, LOADLIN will be copied to root's home directory as a
.ZIP file. There is no automatic setup process for LOADLIN. You will need to copy the
Linux kernel (typically <tt class="FILENAME">/boot/vmlinuz</tt>) and the LOADLIN file
from root's home directory to the DOS partition.</p>
<p>LOADLIN is useful if you would like to make a boot menu on your DOS partition. A menu
could be added to your <tt class="FILENAME">AUTOEXEC.BAT</tt> file that would allow you
to pick between Linux or DOS. A choice of Linux would run LOADLIN, thus booting your
Slackware system. This <tt class="FILENAME">AUTOEXEC.BAT</tt> file under Windows 95 will
provide a sufficient boot menu:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="PROGRAMLISTING">
@ECHO OFF
SET PROMPT=$P$G
SET PATH=C:\WINDOWS;C:\WINDOWS\COMMAND;C:\
CLS
ECHO Please Select Your Operating System:
ECHO.
ECHO [1] Slackware Linux
ECHO [2] Windows 95
ECHO.
CHOICE /C:12 "Selection? -> "
IF ERRORLEVEL 2 GOTO WIN
IF ERRORLEVEL 1 GOTO LINUX
:WIN
CLS
ECHO Starting Windows 95...
WIN
GOTO END
:LINUX
ECHO Starting Slackware Linux...
CD \LINUX
LOADLIN C:\LINUX\VMLINUZ ROOT=<root partition device> RO
GOTO END
:END
</pre>
</td>
</tr>
</table>
<p>You will want to specify your root partition as a Linux device name, like <tt
class="FILENAME">/dev/hda2</tt> or something else. You can always use LOADLIN at the
command line. You simply use it in the same manner as it is in the example above. The
LOADLIN documentation comes with many examples on how to use it.</p>
</div>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="BOOTING-DUAL" name="BOOTING-DUAL">7.3 Dual Booting</a></h2>
<p>Many users set up their computers to boot Slackware Linux and another operating
system. We've described several typical dual boot scenarios below, in case you are having
difficulty setting up your system.</p>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="BOOTING-DUAL-WINDOWS" name="BOOTING-DUAL-WINDOWS">7.3.1
Windows</a></h3>
<p>Setting up a computer with both MS Windows and Linux is probably the most common dual
boot scenario. There are numerous ways you can setup the booting, but this section will
cover two.</p>
<p>Often times when setting up a dual boot system, a person will devise a perfect plan
for where everything should go but mess up the installation order. It is very important
to understand that operating systems need to be installed in a certain order for a dual
boot setup to work. Linux always offers control over what, if anything, gets written to
the Master Boot Record. Therefore, it's always advisable to install Linux last. Windows
should be installed first, since it will always write its booter to the Master Boot
Record, overwriting any entry Linux may have put there.</p>
<div class="SECT3">
<hr />
<h4 class="SECT3"><a id="AEN2577" name="AEN2577">7.3.1.1 Using LILO</a></h4>
<p>Most people will want to use LILO to chose between Linux and Windows. As stated above,
you should install Windows first, then Linux.</p>
<p>Let's say you have a 40GB IDE hard disk as the only drive in your system. Let's also
say that you want to give half of that space to Windows and half of that space to Linux.
This will present a problem when trying to boot Linux.</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="PROGRAMLISTING">
20GB Windows boot (C:)
1GB Linux root (/)
19GB Linux /usr (/usr)
</pre>
</td>
</tr>
</table>
<p>You would also want to set aside an adequate amount of space for a Linux swap
partition. The unwritten rule is to use twice the amount of RAM you have in disk space. A
64MB system would have 128MB of swap, and so on. Adequate swap space is the discussion of
many flames on IRC and Usenet. There's no truly “right” way to do it, but
sticking with the rule above should be sufficient.</p>
<p>With your partitions laid out, you should proceed to install Windows. After that is
set up and working, you should install Linux. The LILO installation needs special
attention. You will want to select the expert mode for installing LILO.</p>
<p>Begin a new LILO configuration. You will want to install it to Master Boot Record so
that it can be used to choose between the two operating systems. From the menu, add your
Linux partition and add your Windows (or DOS) partition. Once that's complete, you can
install LILO.</p>
<p>Reboot the computer. LILO should load and will display a menu letting you select
between the operating systems you have installed. Select the name of the OS you wish to
load (these names were selected when you setup LILO).</p>
<p>LILO is quite a configurable boot loader. It's not just limited to booting Linux or
DOS. It can boot just about anything. The man pages for <tt class="COMMAND">lilo</tt>(8)
and <tt class="FILENAME">lilo.conf</tt>(5) provide more detailed information.</p>
<p>What if LILO doesn't work? There are instances where LILO just won't work on a
particular machine. Fortunately, there is another way to dual boot Linux and Windows.</p>
</div>
<div class="SECT3">
<hr />
<h4 class="SECT3"><a id="AEN2591" name="AEN2591">7.3.1.2 Using LOADLIN</a></h4>
<p>This method can be used if LILO doesn't work on your system, or if you just don't want
to set up LILO. This method is also ideal for the user that reinstalls Windows often.
Each time you reinstall Windows, it will overwrite the Master Boot Record, thus
destroying any LILO installation. With LOADLIN, you are not subject to that problem. The
biggest disadvantage is that you can only use LOADLIN to boot Linux.</p>
<p>With LOADLIN, you can install the operating systems in any order desired. Be careful
about installing things to the Master Boot Record, you do not want to do that. LOADLIN
relies on the Windows partition being bootable. So during the Slackware installation,
make sure you skip the LILO setup.</p>
<p>After installing the operating systems, copy the <tt class="FILENAME">loadlin<var
class="REPLACEABLE">X</var>.zip</tt> (where <var class="REPLACEABLE">X</var> is a version
number, such as <var class="LITERAL">16a</var>) file from root's home directory to your
Windows partition. Also copy your kernel image to the Windows partition. You will need to
be in Linux for this to work. This example shows how to do this:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">#</samp> <kbd class="USERINPUT">mkdir /win</kbd>
<samp class="PROMPT">#</samp> <kbd class="USERINPUT">mount -t vfat /dev/hda1 /win</kbd>
<samp class="PROMPT">#</samp> <kbd class="USERINPUT">mkdir /win/linux</kbd>
<samp class="PROMPT">#</samp> <kbd class="USERINPUT">cd /root</kbd>
<samp class="PROMPT">#</samp> <kbd class="USERINPUT">cp loadlin* /win/linux</kbd>
<samp class="PROMPT">#</samp> <kbd class="USERINPUT">cp /boot/vmlinuz /win/linux</kbd>
<samp class="PROMPT">#</samp> <kbd class="USERINPUT">cd /win/linuz</kbd>
<samp class="PROMPT">#</samp> <kbd class="USERINPUT">unzip loadlin16a.zip</kbd>
</pre>
</td>
</tr>
</table>
<p>That will create a <tt class="FILENAME">C:\LINUX</tt> directory on your Windows
partition (assuming it's <tt class="FILENAME">/dev/hda1</tt>) and copy over the necessary
stuff for LOADLIN. After doing this, you will need to reboot into Windows to setup a boot
menu.</p>
<p>Once in Windows, get to a DOS prompt. First, we need to make sure the system is set to
not boot into the graphical interface.</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
C:\> <kbd class="USERINPUT">cd \</kbd>
C:\> <kbd class="USERINPUT">attrib -r -a -s -h MSDOS.SYS</kbd>
C:\> <kbd class="USERINPUT">edit MSDOS.SYS</kbd>
</pre>
</td>
</tr>
</table>
<p>Add this line to the file:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="PROGRAMLISTING">
BootGUI=0
</pre>
</td>
</tr>
</table>
<p>Now save the file and exit the editor. Now edit <tt
class="FILENAME">C:\AUTOEXEC.BAT</tt> so we can add a boot menu. The following provides
an example of what a boot menu block in <tt class="FILENAME">AUTOEXEC.BAT</tt> would look
like:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="PROGRAMLISTING">
cls
echo System Boot Menu
echo.
echo 1 - Linux
echo 2 - Windows
echo.
choice /c:12 "Selection? -> "
if errorlevel 2 goto WIN
if errorlevel 1 goto LINUX
:LINUX
cls
echo "Starting Linux..."
cd \linux
loadlin c:\linux\vmlinuz root=/dev/hda2 ro
goto END
:WIN
cls
echo "Starting Windows..."
win
goto END
:END
</pre>
</td>
</tr>
</table>
<p>The key line is the one that runs LOADLIN. We tell it the kernel to load, the Linux
root partition, and that we want it mounted read-only initially.</p>
<p>The tools for these two methods are provided with Slackware Linux. There are numerous
other booters on the market, but these should work for most dual boot setups.</p>
</div>
<div class="SECT3">
<hr />
<h4 class="SECT3"><a id="AEN2633" name="AEN2633">7.3.1.3 Deprecated Windows NT
Hack</a></h4>
<p>This is the least common dual booting situation. In the days of old, LILO was unable
to boot Windows NT, requiring Linux users to hack NTLDR, which presented several more
problems than dual booting between Windows 9x and Linux. Understand that the following
instructions are deprecated. LILO has been able to boot Windows NT/2000/XP/2003 for many
years now. If you are using a legacy machine though, you may need to use just such a
hack.</p>
<ol type="1">
<li>
<p>Install Windows NT</p>
</li>
<li>
<p>Install Linux, making sure LILO is installed to the superblock of the Linux
partition</p>
</li>
<li>
<p>Get the first 512 bytes of the Linux root partition and store it on the Windows NT
partition</p>
</li>
<li>
<p>Edit <tt class="FILENAME">C:\BOOT.INI</tt> under Windows NT to add a Linux option</p>
</li>
</ol>
<p>Installing Windows NT should be fairly straightforward, as should installing Linux.
From there, it gets a little more tricky. Grabbing the first 512 bytes of the Linux
partition is easier than it sounds. You will need to be in Linux to accomplish this.
Assuming your Linux partition is <tt class="FILENAME">/dev/hda2</tt>, issue this
command:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">#</samp> <kbd
class="USERINPUT">dd if=/dev/hda2 of=/tmp/bootsect.lnx bs=1 count=512</kbd>
</pre>
</td>
</tr>
</table>
<p>That's it. Now you need to copy bootsect.lnx to the Windows NT partition. Here's where
we run into another problem. Linux does not have stable write support for the NTFS
filesystem. If you installed Windows NT and formatted your drive as NTFS, you will need
to copy this file to a FAT floppy and then read from it under Windows NT. If you
formatted the Windows NT drive as FAT, you can simply mount it under Linux and copy the
file over. Either way, you will want to get <tt class="FILENAME">/tmp/bootsect.lnx</tt>
from the Linux drive to <tt class="FILENAME">C:\BOOTSECT.LNX</tt> on the Windows NT
drive.</p>
<p>The last step is adding a menu option to the Windows NT boot menu. Under Windows NT
open a command prompt.</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
C:\WINNT> <kbd class="USERINPUT">cd \</kbd>
C:\> <kbd class="USERINPUT">attrib -r -a -s -h boot.ini</kbd>
C:\> <kbd class="USERINPUT">edit boot.ini</kbd>
</pre>
</td>
</tr>
</table>
<p>Add this line to the end of the file:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="PROGRAMLISTING">
C:\bootsect.lnx="Slackware Linux"
</pre>
</td>
</tr>
</table>
<p>Save the changes and exit the editor. When you reboot Windows NT, you will have a
Linux option on the menu. Choosing it will boot into Linux.</p>
</div>
</div>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="BOOTING-DUAL-LINUX" name="BOOTING-DUAL-LINUX">7.3.2
Linux</a></h3>
<p>Yes, people really do this. This is definitely the easiest dual boot scenario. You can
simply use LILO and add more entries to the <tt class="FILENAME">/etc/lilo.conf</tt>
file. That's all there is to it.</p>
</div>
</div>
</div>
<div class="CHAPTER">
<hr />
<h1><a id="SHELL" name="SHELL"></a>Chapter 8 The Shell</h1>
<p>In a graphical environment, the interface is provided by a program that creates
windows, scrollbars, menus, etc. In a commandline environment, the user interface is
provided by a shell, which interprets commands and generally makes things useable.
Immediately after logging in (which is covered in this chapter), users are put into a
shell and allowed to go about their business. This chapter serves as an introduction to
the shell, and to the most common shell among Linux users-- the Bourne Again Shell
(bash). For more detailed information on anything in this chapter, check out the <tt
class="COMMAND">bash</tt>(1) man page.</p>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="SHELL-USERS" name="SHELL-USERS">8.1 Users</a></h2>
<div class="SECT2">
<h3 class="SECT2"><a id="AEN2678" name="AEN2678">8.1.1 Logging In</a></h3>
<p>So you've booted, and you're looking at something that looks like this:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
Welcome to Linux 2.4.18
Last login: Wed Jan 1 15:59:14 -0500 2005 on tty6.
darkstar login:
</pre>
</td>
</tr>
</table>
<p>Hmm.. nobody said anything about a login. And what's a darkstar? Don't worry; you
probably didn't accidentally fire up a hyperspace comm-link to the Empire's artificial
moon. (I'm afraid the hyperspace comm-link protocol isn't currently supported by the
Linux kernel. Maybe the 2.8 kernel branch will at last provide this oft looked-for
support.) No, darkstar is just the name of one of our computers, and its name gets
stamped on as the default. If you specified a name for your computer during setup, you
should see it instead of darkstar.</p>
<p>As for the login... If this is your first time, you'll want to log in as <tt
class="USERNAME">root</tt>. You'll be prompted for a password; if you set one during the
setup process, that's what it's looking for. If not, just hit enter. That's it-- you're
in!</p>
</div>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="AEN2693" name="AEN2693">8.1.2 Root: The Superuser</a></h3>
<p>Okay, who or <span class="emphasis"><i class="EMPHASIS">what</i></span> is <tt
class="USERNAME">root</tt>? And what's it doing with an account on <span
class="emphasis"><i class="EMPHASIS">your</i></span> system?</p>
<p>Well, in the world of Unix and similar operating systems (like Linux), there are users
and then there are users. We'll go into this in more detail later, but the important
thing to know now is that <tt class="USERNAME">root</tt> is the user above all users; <tt
class="USERNAME">root</tt> is all-powerful and all-knowing, and <span class="emphasis"><i
class="EMPHASIS">nobody</i></span> disobeys <tt class="USERNAME">root</tt>. It just isn't
allowed. <tt class="USERNAME">root</tt> is what we call a “superuser”, and
rightly so. And best of all, <tt class="USERNAME">root</tt> is <span class="emphasis"><i
class="EMPHASIS">you</i></span>.</p>
<p>Cool, huh?</p>
<p>If you're not sure: yes, that's very cool. The catch is, though, that root is
inherently allowed to break anything it so desires. You might want to skip ahead to <a
href="#ESSENTIAL-SYSADMIN-USERS-SCRIPTS">Section 12.1.1</a> and see about adding a user;
then login as that user and work from there. The traditional wisdom is that it's best to
only become the superuser when absolutely necessary, so as to minimize the possibility of
accidentally breaking something.</p>
<p>By the way, if you decide you want to be root while you're logged in as someone else,
no problem. Just use the <tt class="COMMAND">su</tt>(1) command. You'll be asked for <tt
class="USERNAME">root's</tt> password and then it will make you <tt
class="USERNAME">root</tt> until you <tt class="COMMAND">exit</tt> or <tt
class="COMMAND">logout</tt>. You can also become any other user using <tt
class="COMMAND">su</tt>, provided you know that user's password: <tt class="COMMAND">su
logan</tt>, for instance, would make you me.</p>
<div class="NOTE">
<table class="NOTE" width="100%" border="0">
<tr>
<td width="25" align="CENTER" valign="TOP"><img src="./imagelib/admon/note.png"
hspace="5" alt="Note" /></td>
<td align="LEFT" valign="TOP">
<p><tt class="USERNAME">root</tt> is allowed to su to any user, without requiring their
password.</p>
</td>
</tr>
</table>
</div>
</div>
</div>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="SHELL-COMMAND-LINE" name="SHELL-COMMAND-LINE">8.2 The Command
Line</a></h2>
<div class="SECT2">
<h3 class="SECT2"><a id="SHELL-COMMAND-LINE-RUNNING"
name="SHELL-COMMAND-LINE-RUNNING">8.2.1 Running Programs</a></h3>
<p>It's hard to get much accomplished without running a program; you might be able to
prop something up with your computer or hold a door open, and some will make the most
lovely humming noise when running, but that's really about it. And I think we can all
agree that its use as a humming doorstop isn't what brought the personal computer the
popularity it now enjoys.</p>
<p>So, remember how almost everything in Linux is a file? Well, that goes for programs,
too. Every command you run (that isn't built into the shell) resides as a file somewhere.
You run a program simply by specifying the full path to it.</p>
<p>For instance, remember that <tt class="COMMAND">su</tt> command from the last section?
Well, it's actually in the <tt class="FILENAME">/bin</tt> directory: <tt
class="COMMAND">/bin/su</tt> would run it nicely.</p>
<p>So why, then, does just typing <tt class="COMMAND">su</tt> work? After all, you didn't
say it was in <tt class="FILENAME">/bin</tt>. It could just as easily have been in <tt
class="FILENAME">/usr/local/share</tt>, right? How did it <span class="emphasis"><i
class="EMPHASIS">know</i></span>? The answer to that lies in the <tt
class="ENVAR">PATH</tt> environment variable; most shells have either <tt
class="ENVAR">PATH</tt> or something very much like <tt class="ENVAR">PATH</tt>. It
basically contains a list of directories to look in for programs you try to run. So when
you ran <tt class="COMMAND">su</tt>, your shell ran through its list of directories,
checking each one for an executable file called <tt class="COMMAND">su</tt> that it could
run; the first one it came to, it ran. This happens whenever you run a program without
specifying a full path to it; if you get a ““<tt class="ERRORNAME">Command
not found</tt>”” error, that only means that the program you tried to run
isn't in your <tt class="ENVAR">PATH</tt>. (Of course, this would be true if the program
doesn't exist at all...) We'll discuss environment variables in more depth in <a
href="#SHELL-BASH-ENVIRONMENT">Section 8.3.1</a>.</p>
<p>Remember also that “<tt class="FILENAME">.</tt>” is shorthand for the
current directory, so if you happened to be in <tt class="FILENAME">/bin</tt>, <tt
class="FILENAME">./su</tt> would have worked as an explicit full path.</p>
</div>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="SHELL-COMMAND-LINE-WILDCARD"
name="SHELL-COMMAND-LINE-WILDCARD">8.2.2 Wildcard Matching</a></h3>
<p>Nearly every shell recognizes some characters as being substitutes or abbreviations
that mean anything goes here. Such characters are aptly named wildcards; the most common
are <var class="LITERAL">*</var> and <var class="LITERAL">?</var>. By convention, <var
class="LITERAL">?</var> usually matches any single character. For instance, suppose
you're in a directory with three files: <tt class="FILENAME">ex1.txt</tt>, <tt
class="FILENAME">ex2.txt</tt>, and <tt class="FILENAME">ex3.txt</tt>. You want to copy
all of those files (using the <tt class="COMMAND">cp</tt> command we cover in <a
href="#FILE-COMMANDS-COPYMOVE-CP">Section 10.5.1</a>) to another directory, say <tt
class="FILENAME">/tmp</tt>. Well, typing <tt class="COMMAND">cp ex1.txt ex2.txt ex3.txt
/tmp</tt> is entirely too much work. It's much easier to type <tt class="COMMAND">cp
ex?.txt /tmp</tt>; the <var class="LITERAL">?</var> will match each of the characters
“1”, “2”, and “3”, and each in turn will be
substituted in.</p>
<p>What's that you say? That's <span class="emphasis"><i
class="EMPHASIS">still</i></span> too much work? You're right. It's appalling; we have
labor laws to protect us from that sort of thing. Fortunately, we also have <var
class="LITERAL">*</var>. As was already mentioned, <var class="LITERAL">*</var> matches
“any number of characters”, including 0. So if those three files were the
only ones in the directory, we could have simply said <tt class="COMMAND">cp * /tmp</tt>
and gotten them all in one fell swoop. Suppose, though, that there is also a file called
<tt class="FILENAME">ex.txt</tt> and one called <tt class="FILENAME">hejaz.txt</tt>. We
want to copy <tt class="FILENAME">ex.txt</tt> but not <tt
class="FILENAME">hejaz.txt</tt>; <tt class="COMMAND">cp ex* /tmp</tt> will do that for
us.</p>
<p><tt class="COMMAND">cp ex?.txt /tmp</tt>, would, of course, only get our original
three files; there's no character in <tt class="FILENAME">ex.txt</tt> to match that <var
class="LITERAL">?</var>, so it would be left out.</p>
<p>Another common wildcard is the bracket pair <var class="LITERAL">[ ]</var>. Any
characters inside the brackets will be substituted in place of the <var class="LITERAL">[
]</var> to find matches. Sound confusing? It's not too bad. Suppose for instance, we have
a directory containing the following 8 files: <tt class="FILENAME">a1</tt>, <tt
class="FILENAME">a2</tt>, <tt class="FILENAME">a3</tt>, <tt class="FILENAME">a4</tt>, <tt
class="FILENAME">aA</tt>, <tt class="FILENAME">aB</tt>, <tt class="FILENAME">aC</tt>, and
<tt class="FILENAME">aD</tt> . We want to only find the files ending in numbers; <var
class="LITERAL">[ ]</var> will do this for us.</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">ls a[1-4]</kbd>
a1 a2 a3 a4
</pre>
</td>
</tr>
</table>
<p>But what we really want is just <tt class="FILENAME">a1</tt>, <tt
class="FILENAME">a2</tt>, and <tt class="FILENAME">a4</tt>? In the previous example we
used - to mean all values between 1 and 4. We can also separate individual entries with
commas.</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">ls a[1,2,4]</kbd>
a1 a2 a4
</pre>
</td>
</tr>
</table>
<p>I know what you're thinking now, “Well what about letters?” Linux is
case-sensitive, meaning that <var class="LITERAL">a</var> and <var
class="LITERAL">A</var> are different characters and are only related in your mind.
Capitals always come before lowercase letters, so <var class="LITERAL">A</var> and <var
class="LITERAL">B</var> come before <var class="LITERAL">a</var> and <var
class="LITERAL">b</var>. Continuing with our earlier example, if we wanted files <tt
class="FILENAME">a1</tt>, and <tt class="FILENAME">A1</tt>, we can find these quickly
with <var class="LITERAL">[ ]</var>.</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">ls [A,a]1</kbd>
A1 a1
</pre>
</td>
</tr>
</table>
<p>Note, that if we had included a hyphen instead of a comma, we would have gotten
incorrect results.</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">ls [A-a]1</kbd>
A1 B1 C1 D1 a1
</pre>
</td>
</tr>
</table>
<p>You can also combine hyphen and comma strings.</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">ls [A,a-d]</kbd>
A1 a1 b1 c1 d1
</pre>
</td>
</tr>
</table>
</div>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="SHELL-COMMAND-LINE-PIPING"
name="SHELL-COMMAND-LINE-PIPING">8.2.3 Input/Output Redirection and Piping</a></h3>
<p>(Here comes something cool.)</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">ps > blargh</kbd>
</pre>
</td>
</tr>
</table>
<p>Y'know what that is? That's me running <tt class="COMMAND">ps</tt> to see which
processes are running; <tt class="COMMAND">ps</tt> is covered in <a
href="#PROCESS-CONTROL-PS">Section 11.3</a>. That's not the cool part. The cool part is
<var class="LITERAL">> blargh</var>, which means, roughly, take the output from <tt
class="COMMAND">ps</tt> and write it to a file called <tt class="FILENAME">blargh</tt>.
But wait, it gets cooler.</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">ps | less</kbd>
</pre>
</td>
</tr>
</table>
<p>That one takes the output from <tt class="COMMAND">ps</tt> and pipes it through <tt
class="COMMAND">less</tt>, so I can scroll through it at my leisure.</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">ps >> blargh</kbd>
</pre>
</td>
</tr>
</table>
<p>This is the third most commonly used redirector; it does the same thing as
“>”, except that “>>” will append output from <tt
class="COMMAND">ps</tt> to the file <tt class="FILENAME">blargh</tt>, if said file
exists. If not, just like “>”, it will be created. (“>”
will obliterate the current contents of <tt class="FILENAME">blargh</tt>.)</p>
<p>There is also a “<” operator, which means take your input from the
following, but it's not used nearly so often.</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd
class="USERINPUT">fromdos < dosfile.txt > unixfile.txt</kbd>
</pre>
</td>
</tr>
</table>
<p>Redirection gets really fun when you start piling it up:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">ps | tac >> blargh</kbd>
</pre>
</td>
</tr>
</table>
<p>That will run <tt class="COMMAND">ps</tt>, reverse the lines of its output, and append
those to the file <tt class="FILENAME">blargh</tt>. You can stack as many of these up as
you want; just be careful to remember that they get interpreted from left to right.</p>
<p>See the <tt class="COMMAND">bash</tt>(1) man page for more detailed information on
redirection.</p>
</div>
</div>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="SHELL-BASH" name="SHELL-BASH">8.3 The Bourne Again Shell
(bash)</a></h2>
<div class="SECT2">
<h3 class="SECT2"><a id="SHELL-BASH-ENVIRONMENT" name="SHELL-BASH-ENVIRONMENT">8.3.1
Environment Variables</a></h3>
<p>A Linux system is a complex beast, and there's a lot to keep track of, a lot of little
details that come into play in your normal interactions with various programs (some of
which you might not even need to be aware of). Nobody wants to pass a bunch of options to
every program that gets run, telling it what kind of terminal is being used, the hostname
of the computer, how their prompt should look...</p>
<p>So as a coping mechanism, users have what's called an environment. The environment
defines the conditions in which programs run, and some of this definition is variable;
the user can alter and play with it, as is only right in a Linux system. Pretty much any
shell will have environment variables (if not, it's probably not a very useable shell).
Here we will give an overview of the commands bash provides for manipulating its
environment variables.</p>
<p><tt class="COMMAND">set</tt> by itself will show you all of the environment variables
that are currently defined, as well as their values. Like most <tt
class="COMMAND">bash</tt> built-ins, it can also do several other things (with
parameters); we'll leave it to the <tt class="COMMAND">bash</tt>(1) man page to cover
that, though. <a href="#EX-SHELL-BASH-ENVIRONMENT">Example 8-1</a> shows an excerpt from
a <tt class="COMMAND">set</tt> command run on one of the author's computers. Notice in
this example the <tt class="ENVAR">PATH</tt> variable that was discussed earlier.
Programs in any of those directories can be run simply by typing the base filename.</p>
<div class="EXAMPLE"><a id="EX-SHELL-BASH-ENVIRONMENT"
name="EX-SHELL-BASH-ENVIRONMENT"></a>
<p><b>Example 8-1. Listing Environment Variables with <tt
class="COMMAND">set</tt></b></p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">set</kbd>
PATH=/usr/local/lib/qt/bin:/usr/local/bin:/usr/bin:/bin:/usr/X11R6/bin:
/usr/openwin/bin:/usr/games:.:/usr/local/ssh2/bin:/usr/local/ssh1/bin:
/usr/share/texmf/bin:/usr/local/sbin:/usr/sbin:/home/logan/bin
PIPESTATUS=([0]="0")
PPID=4978
PS1='\h:\w\$ '
PS2='> '
PS4='+ '
PWD=/home/logan
QTDIR=/usr/local/lib/qt
REMOTEHOST=ninja.tdn
SHELL=/bin/bash
</pre>
</td>
</tr>
</table>
</div>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">unset <var
class="REPLACEABLE">VARIABLE</var></kbd>
</pre>
</td>
</tr>
</table>
<p><tt class="COMMAND">unset</tt> will remove any variables that you give it, wiping out
both the variable and its value; <tt class="COMMAND">bash</tt> will forget that variable
ever existed. (Don't worry. Unless it's something you explicitly defined in that shell
session, it'll probably get redefined in any other session.)</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">export <var
class="REPLACEABLE">VARIABLE=some_value</var></kbd>
</pre>
</td>
</tr>
</table>
<p>Now, <tt class="COMMAND">export</tt> is truly handy. Using it, you give the
environment variable <tt class="ENVAR">VARIABLE</tt> the value “<var
class="LITERAL">some_value</var>”; if <tt class="ENVAR">VARIABLE</tt> didn't exist,
it does now. If <tt class="ENVAR">VARIABLE</tt> already had a value, well, it's gone.
That's not so good, if you're just trying to add a directory to your <tt
class="ENVAR">PATH</tt>. In that case, you probably want to do something like this:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">export PATH=$PATH:<var
class="REPLACEABLE">/some/new/directory</var></kbd>
</pre>
</td>
</tr>
</table>
<p>Note the use of <tt class="ENVAR">$PATH</tt> there: when you want <tt
class="COMMAND">bash</tt> to interpret a variable (replace it with its value), tack a
<var class="LITERAL">$</var> onto the beginning of the variable's name. For instance, <tt
class="COMMAND">echo $PATH</tt> will echo the value of <tt class="ENVAR">PATH</tt>, in my
case:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">echo $PATH</kbd>
/usr/local/lib/qt/bin:/usr/local/bin:/usr/bin:/bin:/usr/X11R6/bin:
/usr/openwin/bin:/usr/games:.:/usr/local/ssh2/bin:/usr/local/ssh1/bin:
/usr/share/texmf/bin:/usr/local/sbin:/usr/sbin:/home/logan/bin
</pre>
</td>
</tr>
</table>
</div>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="SHELL-BASH-TAB" name="SHELL-BASH-TAB">8.3.2 Tab
Completion</a></h3>
<p>(Here comes something cool again.)</p>
<ol type="1">
<li>
<p>A commandline interface means lots of typing.</p>
</li>
<li>
<p>Typing is work.</p>
</li>
<li>
<p>Nobody likes work.</p>
</li>
</ol>
<p>From 3 and 2, we can determine that (4) nobody likes typing. Fortunately, <tt
class="COMMAND">bash</tt> saves us from (5) (nobody likes a commandline interface).</p>
<p>How does <tt class="COMMAND">bash</tt> accomplish this wonderful feat, you ask? In
addition to the wildcard expansion we discussed before, <tt class="COMMAND">bash</tt>
features tab completion.</p>
<p>Tab completion works something like this: You're typing the name of a file. Maybe it's
in your <tt class="ENVAR">PATH</tt>, maybe you're typing it out explicitly. All you have
to do is type enough of the filename to uniquely identify it. Then hit the tab key. <tt
class="COMMAND">bash</tt> will figure out what you want and finish typing it for you!</p>
<p>Example time. <tt class="FILENAME">/usr/src</tt> contains two subdirectories: <tt
class="FILENAME">/usr/src/linux</tt> and <tt class="FILENAME">/usr/src/sendmail</tt>. I
want to see what's in <tt class="FILENAME">/usr/src/linux</tt>. So I just type <tt
class="COMMAND">ls /usr/src/l</tt>, hit the <kbd class="USERINPUT">TAB</kbd> key, and <tt
class="COMMAND">bash</tt> gives me <tt class="COMMAND">ls /usr/src/linux</tt>.</p>
<p>Now, suppose there are two directories <tt class="FILENAME">/usr/src/linux</tt> and
<tt class="FILENAME">/usr/src/linux-old</tt>; If I type <tt
class="FILENAME">/usr/src/l</tt> and hit <kbd class="USERINPUT">TAB</kbd>, <tt
class="COMMAND">bash</tt> will fill in as much as it can, and I'll get <tt
class="FILENAME">/usr/src/linux</tt>. I can stop there, or I can hit <kbd
class="USERINPUT">TAB</kbd> again, and <tt class="COMMAND">bash</tt> will show a list of
directories that match what I've typed so far.</p>
<p>Hence, less typing (and hence, people can like commandline interfaces). I told you it
was cool.</p>
</div>
</div>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="SHELL-VT" name="SHELL-VT">8.4 Virtual Terminals</a></h2>
<p>So you're in the middle of working on something and you decide you need to do
something else. You could just drop what you're doing and switch tasks, but this is a
multi-user system, right? And you can log in as many times simultaneously as you want,
right? So why should you have to do one thing at a time?</p>
<p>You don't. We can't all have multiple keyboards, mice, and monitors for one machine;
chances are most of us don't want them. Clearly, hardware isn't the solution. That leaves
software, and Linux steps up on this one, providing “virtual terminals”, or
“VTs”.</p>
<p>By pressing <kbd class="USERINPUT">Alt</kbd> and a function key, you can switch
between virtual terminals; each function key corresponds to one. Slackware has logins on
6 VTs by default. <b class="KEYCAP">Alt</b>+<b class="KEYCAP">F2</b> will take you to the
second one, <b class="KEYCAP">Alt</b>+<b class="KEYCAP">F3</b> to the third, etc.</p>
<p>The rest of the function keys are reserved for X sessions. Each X session uses its own
VT, beginning with the seventh (<b class="KEYCAP">Alt</b>+<b class="KEYCAP">F7</b>) and
going up. When in X, the <b class="KEYCAP">Alt</b>+<b class="KEYCAP">Function key</b>
combination is replaced with <b class="KEYCAP">Ctrl</b>+<b class="KEYCAP">Alt</b>+<b
class="KEYCAP">Function</b>; so if you are in X and want to get back to a text login
(without exiting your X session), <b class="KEYCAP">Ctrl</b>+<b class="KEYCAP">Alt</b>+<b
class="KEYCAP">F3</b> will take you to the third. (<b class="KEYCAP">Alt</b>+<b
class="KEYCAP">F7</b> will take you back, assuming you're using the first X session.)</p>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="AEN3024" name="AEN3024">8.4.1 Screen</a></h3>
<p>But what about situations where there are no virtual terminals? What then?
Fortunately, slackware includes a beautiful screen manager aptly named <tt
class="COMMAND">screen</tt>. <tt class="COMMAND">screen</tt> is a terminal emulator that
has virtual terminal like capabilities. Executing <tt class="COMMAND">screen</tt> flashes
a brief introduction, then dumps to a terminal. Unlike the standard virtual terminals,
<tt class="COMMAND">screen</tt> has its own commands. All <tt class="COMMAND">screen</tt>
commands are prefixed with a <b class="KEYCAP">Crtl</b>+<b class="KEYCAP">A</b>
keystroke. For example, <b class="KEYCAP">Ctrl</b>+<b class="KEYCAP">A</b>+<b
class="KEYCAP">C</b> will create a new terminal session. <b class="KEYCAP">Ctrl</b>+<b
class="KEYCAP">A</b>+<b class="KEYCAP">N</b> will switch to the next terminal. <b
class="KEYCAP">Ctrl</b>+<b class="KEYCAP">A</b>+<b class="KEYCAP">P</b> switches to the
previous terminal.</p>
<p><tt class="COMMAND">screen</tt> also supports detaching and re-attaching to <tt
class="COMMAND">screen</tt> sessions which is particularly useful for remote sessions via
<tt class="COMMAND">ssh</tt> and <tt class="COMMAND">telnet</tt>, (more on those later).
<b class="KEYCAP">Ctrl</b>+<b class="KEYCAP">A</b>+<b class="KEYCAP">D</b> will detach
from the currently running screen. Executing <tt class="COMMAND">screen -r</tt> will list
all currently running screen sessions you may reattach to.</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">screen -r</kbd>
There are several suitable screens on:
1212.pts-1.redtail (Detached)
1195.pts-1.redtail (Detached)
1225.pts-1.redtail (Detached)
17146.pts-1.sanctuary (Dead ???)
Remove dead screens with 'screen -wipe'.
Type "screen [-d] -r [pid.]tty.host" to resume one of them.
</pre>
</td>
</tr>
</table>
<p>Running <tt class="COMMAND">screen -r 1212</tt> would reattach to the first screen
listed. I mentioned earlier how useful this was for remote sessions. If I were to login
to a remote slackware server via <tt class="COMMAND">ssh</tt>, and my connection was
severed by some chance occurrence such as a local power failure, whatever I was doing at
that moment would instantly perish, which can be a horrible thing for your server. Using
<tt class="COMMAND">screen</tt> prevents this by detaching my session if my connection is
dropped. Once my connection is restored, I can reattach to my screen session and resume
right where I left off.</p>
</div>
</div>
</div>
<div class="CHAPTER">
<hr />
<h1><a id="FILESYSTEM-STRUCTURE" name="FILESYSTEM-STRUCTURE"></a>Chapter 9 Filesystem
Structure</h1>
<p>We have already discussed the directory structure in Slackware Linux. By this point,
you should be able to find files and directories that you need. But there is more to the
filesystem than just the directory structure.</p>
<p>Linux is a multiuser operating system. Every aspect of the system is multiuser, even
the filesystem. The system stores information like who owns a file and who can read it.
There are other unique parts about the filesystems, such as links and NFS mounts. This
section explains these, as well as the multiuser aspects of the filesystem.</p>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="FILESYSTEM-STRUCTURE-OWNERSHIP"
name="FILESYSTEM-STRUCTURE-OWNERSHIP">9.1 Ownership</a></h2>
<p>The filesystem stores ownership information for each file and directory on the system.
This includes what user and group own a particular file. The easiest way to see this
information is with the <tt class="COMMAND">ls</tt> command:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">ls -l /usr/bin/wc</kbd>
-rwxr-xr-x 1 root bin 7368 Jul 30 1999 /usr/bin/wc
</pre>
</td>
</tr>
</table>
<p>We are interested in the third and fourth columns. These contain the username and
group name that owns this file. We see that the user “<tt
class="USERNAME">root</tt>” and the group “<tt
class="USERNAME">bin</tt>” own this file.</p>
<p>We can easily change the file owners with the <tt class="COMMAND">chown</tt>(1) (which
means “change owner”) and <tt class="COMMAND">chgrp</tt>(1) (which means
“change group”) commands. To change the file owner to <tt
class="USERNAME">daemon</tt>, we would use <tt class="COMMAND">chown</tt>:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">#</samp> <kbd class="USERINPUT">chown daemon /usr/bin/wc</kbd>
</pre>
</td>
</tr>
</table>
<p>To change the group owner to “<tt class="USERNAME">root</tt>”, we would
use <tt class="COMMAND">chgrp</tt>:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">#</samp> <kbd class="USERINPUT">chgrp root /usr/bin/wc</kbd>
</pre>
</td>
</tr>
</table>
<p>We can also use <tt class="COMMAND">chown</tt> to specify the user and group owners
for a file:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">#</samp> <kbd class="USERINPUT">chown daemon:root /usr/bin/wc</kbd>
</pre>
</td>
</tr>
</table>
<p>In the above example, the user could have used a period instead of a colon. The result
would have been the same; however, the colon is considered better form. Use of the period
is deprecated and may be removed from future versions of <tt class="COMMAND">chown</tt>
to allow usernames with periods in them. These usernames tend to be very popular with
Windows Exchange Servers and are encountered most commonly in email addresses such as:
<var class="LITERAL">mr.jones@example.com</var>. In slackware, administrators are advised
to stay away from such usernames because some scripts still use the period to indicate
the user and group of a file or directory. In our example, <tt class="COMMAND">chmod</tt>
would interpret <var class="LITERAL">mr.jones</var> as user “mr” and group
“jones”.</p>
<p>File ownership is a very important part of using a Linux system, even if you are the
only user. You sometimes need to fix ownerships on files and device nodes.</p>
</div>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="FILESYSTEM-STRUCTURE-PERMISSIONS"
name="FILESYSTEM-STRUCTURE-PERMISSIONS">9.2 Permissions</a></h2>
<p>Permissions are the other important part of the multiuser aspects of the filesystem.
With these, you can change who can read, write, and execute files.</p>
<p>The permission information is stored as four octal digits, each specifying a different
set of permissions. There are owner permissions, group permissions, and world
permissions. The fourth octal digit is used to store special information such as set user
ID, set group ID, and the sticky bit. The octal values assigned to the permission modes
are (they also have letters associated with them that are displayed by programs such as
<tt class="COMMAND">ls</tt> and can be used by <tt class="COMMAND">chmod</tt>):</p>
<div class="TABLE"><a id="AEN3142" name="AEN3142"></a>
<p><b>Table 9-1. Octal Permission Values</b></p>
<table border="0" frame="void" class="CALSTABLE">
<col width="3*" />
<col width="1*" align="CENTER" />
<col width="1*" align="CENTER" />
<thead>
<tr>
<th>Permission Type</th>
<th>Octal Value</th>
<th>Letter Value</th>
</tr>
</thead>
<tbody>
<tr>
<td>“sticky” bit</td>
<td>1</td>
<td>t</td>
</tr>
<tr>
<td>set user ID</td>
<td>4</td>
<td>s</td>
</tr>
<tr>
<td>set group ID</td>
<td>2</td>
<td>s</td>
</tr>
<tr>
<td>read</td>
<td>4</td>
<td>r</td>
</tr>
<tr>
<td>write</td>
<td>2</td>
<td>w</td>
</tr>
<tr>
<td>execute</td>
<td>1</td>
<td>x</td>
</tr>
</tbody>
</table>
</div>
<p>You add the octal values for each permission group. For example, if you want the group
permissions to be “read” and “write”, you would use
“6” in the group portion of the permission information.</p>
<p><tt class="COMMAND">bash</tt>'s default permissions are:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">ls -l /bin/bash</kbd>
-rwxr-xr-x 1 root bin 477692 Mar 21 19:57 /bin/bash
</pre>
</td>
</tr>
</table>
<p>The first dash would be replaced with a “d” if this was a directory. The
three permission groups (owner, group, and world) are displayed next. We see that the
owner has read, write, and execute permissions (<var class="LITERAL">rwx</var>). The
group has only read and execute (<var class="LITERAL">r-x</var>). And everyone else has
only read and execute (<var class="LITERAL">r-x</var>).</p>
<p>How would we set permissions on another file to resemble <tt
class="COMMAND">bash</tt>'s? First, let's make an example file:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">touch /tmp/example</kbd>
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">ls -l /tmp/example</kbd>
-rw-rw-r--- 1 david users 0 Apr 19 11:21 /tmp/example
</pre>
</td>
</tr>
</table>
<p>We will use <tt class="COMMAND">chmod</tt>(1) (which means “change mode”)
to set the permissions on the example file. Add the octal numbers for the permissions you
want. For the owner to have read, write, and execute, we would have a value of <var
class="LITERAL">7</var>. Read and execute would have <var class="LITERAL">5</var>. Run
those together and pass them to <tt class="COMMAND">chmod</tt> like this:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">chmod 755 /tmp/example</kbd>
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">ls -l /tmp/example</kbd>
-rwxr-xr-x 1 david users 0 Apr 19 11:21 /tmp/example
</pre>
</td>
</tr>
</table>
<p>Now you may be thinking, “Why didn't it just create a file with those
permissions in the first place?” Well the answer is simple. <tt
class="COMMAND">bash</tt> includes a nice little built-in called <tt
class="COMMAND">umask</tt>. This is included with most Unix shells as well, and controls
what file permissions are assigned to newly created files. We discussed <tt
class="COMMAND">bash</tt> built-ins to some degree in <a
href="#SHELL-BASH-ENVIRONMENT">Section 8.3.1</a>. <tt class="COMMAND">umask</tt> takes a
little getting used to. It works very similar to <tt class="COMMAND">chmod</tt>, only in
reverse. You specify the octal values you do not wish to have present in newly created
files. The default umask value is <var class="LITERAL">0022</var>.</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">umask</kbd>
0022
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">umask 0077</kbd>
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">touch tempfile</kbd>
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">ls -l tempfile</kbd>
-rw-------- 1 david users 0 Apr 19 11:21 tempfile
</pre>
</td>
</tr>
</table>
<p>See the man page for <tt class="COMMAND">bash</tt> for more information.</p>
<p>To set special permissions with <tt class="COMMAND">chmod</tt>, add the numbers
together and place them in the first column. For example, to make it set user ID and set
group ID, we use 6 as the first column:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">chmod 6755 /tmp/example</kbd>
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">ls -l /tmp/example</kbd>
-rwsr-sr-x 1 david users 0 Apr 19 11:21 /tmp/example
</pre>
</td>
</tr>
</table>
<p>If the octal values confuse you, you can use letters with <tt
class="COMMAND">chmod</tt>. The permission groups are represented as:</p>
<div class="INFORMALTABLE"><a id="AEN3246" name="AEN3246"></a>
<table border="0" frame="void" class="CALSTABLE">
<col />
<col />
<tbody>
<tr>
<td>Owner</td>
<td>u</td>
</tr>
<tr>
<td>Group</td>
<td>g</td>
</tr>
<tr>
<td>World</td>
<td>o</td>
</tr>
<tr>
<td>All of the above</td>
<td>a</td>
</tr>
</tbody>
</table>
</div>
<p>To do the above, we would have to use several command lines:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">chmod a+rx /tmp/example</kbd>
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">chmod u+w /tmp/example</kbd>
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">chmod ug+s /tmp/example</kbd>
</pre>
</td>
</tr>
</table>
<p>Some people prefer the letters over the numbers. Either way will result in the same
set of permissions.</p>
<p>The octal format is often faster, and the one you see most often used in shell
scripts. Sometimes the letters are more powerful however. For example, there's no easy
way to change one group of permissions while preserving the other groups on files and
directories when using the octal format. This is trivial with the letters.</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">ls -l /tmp/</kbd>
-rwxr-xr-x 1 alan users 0 Apr 19 11:21 /tmp/example0
-rwxr-x--- 1 alan users 0 Apr 19 11:21 /tmp/example1
----r-xr-x 1 alan users 0 Apr 19 11:21 /tmp/example2
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">chmod g-rwx /tmp/example?</kbd>
-rwx---r-x 1 alan users 0 Apr 19 11:21 /tmp/example0
-rwx------ 1 alan users 0 Apr 19 11:21 /tmp/example1
-------r-x 1 alan users 0 Apr 19 11:21 /tmp/example2
</pre>
</td>
</tr>
</table>
<p>We mentioned set user ID and set group ID permissions in several places above. You may
be wondering what this is. Normally when you run a program, it is operating under your
user account. That is, it has all the permissions that you as a user have. The same is
true for the group. When you run a program, it executes under your current group. With
set user ID permissions, you can force the program to always run as the program owner
(such as “root”). Set group ID is the same, but for the group.</p>
<p>Be careful with this, set user ID and set group ID programs can open major security
holes on your system. If you frequently set user ID programs that are owned by <tt
class="USERNAME">root</tt>, you are allowing anyone to run that program and run it as <tt
class="USERNAME">root</tt>. Since <tt class="USERNAME">root</tt> has no restrictions on
the system, you can see how this would pose a major security problem. In short, it's not
bad to use set user ID and set group ID permissions, just use common sense.</p>
</div>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="FILESYSTEM-STRUCTURE-LINKS"
name="FILESYSTEM-STRUCTURE-LINKS">9.3 Links</a></h2>
<p>Links are pointers between files. With links, you can have files exist in many
locations and be accessible by many names. There are two types of links: hard and
soft.</p>
<p>Hard links are names for a particular file. They can only exist within a single
filesystem and are only removed when the real name is removed from the system. These are
useful in some cases, but many users find the soft link to be more versatile.</p>
<p>The soft link, also called a symbolic link, can point to a file outside of its
filesystem. It is actually a small file containing the information it needs. You can add
and remove soft links without affecting the actual file. And since a symbolic link is
actually a small file containing its own information, they can even point at a directory.
It's rather common to have <tt class="FILENAME">/var/tmp</tt> actually be a symbolic link
to <tt class="FILENAME">/tmp</tt> for example.</p>
<p>Links do not have their own set of permissions or ownerships, but instead reflect
those of the file they point to. Slackware uses mostly soft links. Here is a common
example:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">ls -l /bin/sh</kbd>
lrwxrwxrwx 1 root root 4 Apr 6 12:34 /bin/sh -> bash
</pre>
</td>
</tr>
</table>
<p>The <tt class="COMMAND">sh</tt> shell under Slackware is actually <tt
class="COMMAND">bash</tt>. Removing links is done using <tt class="COMMAND">rm</tt>. The
<tt class="COMMAND">ln</tt> command is used to create links. These commands will be
discussed in more depth in <a href="#FILE-COMMANDS">Chapter 10</a>.</p>
<p>It's very important to be careful about symlinks in particular. Once, I was working on
a machine that was consistently failing to back-up to tape each night. Two symlinks had
been made to directories beneath each other. The back-up software kept appending those
same directories to the tape until it was out of space. Normally, a set of checks will
prevent creating a symlink in this situation, but ours was a special case.</p>
</div>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="FILESYSTEM-STRUCTURE-MOUNTING"
name="FILESYSTEM-STRUCTURE-MOUNTING">9.4 Mounting Devices</a></h2>
<p>As was previously discussed in <a href="#SYSTEM-CONFIGURATION-LAYOUT">Section
4.1.1</a>, all the drives and devices in your computer are one big filesystem. Various
hard drive partitions, CD-ROMs, and floppies are all placed in the same tree. In order to
attach these drives to the filesystem so that you can access them, you have to use the
<tt class="COMMAND">mount</tt>(1) and <tt class="COMMAND">umount</tt>(1) commands.</p>
<p>Some devices are automatically mounted when you boot up your computer. These are
listed in the <tt class="FILENAME">/etc/fstab</tt> file. Anything that you want to be
mounted automatically gets an entry in that file. For other devices, you'll have to issue
a command every time you want to use the device.</p>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="AEN3319" name="AEN3319">9.4.1 <tt
class="FILENAME">fstab</tt></a></h3>
<p>Let's look at an example of the <tt class="FILENAME">/etc/fstab</tt> file:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">cat /etc/fstab</kbd>
/dev/sda1 / ext2 defaults 1 1
/dev/sda2 /usr/local ext2 defaults 1 1
/dev/sda4 /home ext2 defaults 1 1
/dev/sdb1 swap swap defaults 0 0
/dev/sdb3 /export ext2 defaults 1 1
none /dev/pts devpts gid=5,mode=620 0 0
none /proc proc defaults 0 0
/dev/fd0 /mnt ext2 defaults 0 0
/dev/cdrom /mnt/cdrom iso9660 ro 0 0
</pre>
</td>
</tr>
</table>
<p>The first column is the device name. In this case, the devices are five partitions
spread out across two SCSI hard drives, two special filesystems that don't need a device,
a floppy, and a CD-ROM drive. The second column is where the device will be mounted. This
needs to be a directory name, except in the case of a swap partition. The third column is
the filesystem type of the device. For normal Linux filesystems, this will be <var
class="LITERAL">ext2</var> (second extended filesystem). CD-ROM drives are <var
class="LITERAL">iso9660</var>, and Windows-based devices will either be <var
class="LITERAL">msdos</var> or <var class="LITERAL">vfat</var>.</p>
<p>The fourth column is a listing of options that apply to the mounted filesystem.
defaults is fine for just about everything. However, read-only devices should be given
the <var class="LITERAL">ro</var> flag. There are a lot of options that can be used.
Check the <tt class="FILENAME">fstab</tt>(5) man page for more information. The last two
columns are used by <tt class="COMMAND">fsck</tt> and other commands that need to
manipulate the devices. Check the man page for that information as well.</p>
<p>When you install Slackware Linux, the setup program will build much of the <tt
class="FILENAME">fstab</tt> file.</p>
</div>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="AEN3340" name="AEN3340">9.4.2 <tt class="COMMAND">mount</tt> and
<tt class="COMMAND">umount</tt></a></h3>
<p>Attaching another device to your filesystem is easy. All you have to do is use the <tt
class="COMMAND">mount</tt> command, along with a few options. Using <tt
class="COMMAND">mount</tt> can simplified if the device has an entry in the <tt
class="FILENAME">/etc/fstab</tt> file. For example, let's say that I wanted to mount my
CD-ROM drive and that my <tt class="COMMAND">fstab</tt> file looked like the example from
the previous section. I would call <tt class="COMMAND">mount</tt> like so:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">mount /cdrom</kbd>
</pre>
</td>
</tr>
</table>
<p>Since there is an entry in <tt class="FILENAME">fstab</tt> for that mount point, <tt
class="COMMAND">mount</tt> knows what options to use. If there wasn't an entry for that
device, I would have to use several options for <tt class="COMMAND">mount</tt>:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd
class="USERINPUT">mount -t iso9660 -o ro /dev/cdrom /cdrom</kbd>
</pre>
</td>
</tr>
</table>
<p>That command line includes the same information as the example <tt
class="FILENAME">fstab</tt> did, but we'll go over all the parts anyways. The <var
class="OPTION">-t iso9660</var> is the filesystem type of the device to mount. In this
case, it would be the iso9660 filesystem which is what CD-ROM drives most commonly use.
The <var class="OPTION">-o ro</var> tells mount to mount the device read-only. The <tt
class="FILENAME">/dev/cdrom</tt> is the name of the device to mount, and <tt
class="FILENAME">/cdrom</tt> is the location on the filesystem to mount the drive.</p>
<p>Before you can remove a floppy, CD-ROM, or other removable device that is currently
mounted, you'll have to unmount it. That is done using the <tt
class="COMMAND">umount</tt> command. Don't ask where the “n” went because we
couldn't tell you. You can use either the mounted device or the mount point as the
argument to <tt class="COMMAND">umount</tt>. For example, if you wanted to unmount the
CD-ROM from the previous example, either of these commands would work:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">#</samp> <kbd class="USERINPUT">umount /dev/cdrom</kbd>
<samp class="PROMPT">#</samp> <kbd class="USERINPUT">umount /cdrom</kbd>
</pre>
</td>
</tr>
</table>
</div>
</div>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="FILESYSTEM-STRUCTURE-NFS" name="FILESYSTEM-STRUCTURE-NFS">9.5
NFS Mounts</a></h2>
<p>NFS stands for the Network Filesystem. It is not really part of the real filesystem,
but can be used to add parts to the mounted filesystem.</p>
<p>Large Unix environments often times share the same programs, sets of home directories,
and mail spool. The problem of getting the same copy to each machine is solved with NFS.
We can use NFS to share one set of home directories between all of the workstations. The
workstations then mount that NFS share as if it were on their own machines.</p>
<p>See <a href="#NETWORK-CONFIGURATION-NFS-NFS">Section 5.6.2</a> and the man pages for
<tt class="FILENAME">exports</tt>(5), <tt class="COMMAND">nfsd</tt>(8), and <tt
class="COMMAND">mountd</tt>(8) for more information.</p>
</div>
</div>
<div class="CHAPTER">
<hr />
<h1><a id="FILE-COMMANDS" name="FILE-COMMANDS"></a>Chapter 10 Handling Files and
Directories</h1>
<p>Linux aims to the most Unix-like it can be. Traditionally, Unix operating systems have
been command-line oriented. We do have a graphical user interface in Slackware, but the
command-line is still the main level of control for the system. Therefore, it is
important to understand some of the basic file management commands.</p>
<p>The following sections explain the common file management commands and provide
examples of how they are used. There are many other commands, but these will help you get
started. Also, the commands are only briefly discussed here. You will find more detail in
the accompanying man pages for each command.</p>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="FILE-COMMANDS-NAVIGATION" name="FILE-COMMANDS-NAVIGATION">10.1
Navigation : <tt class="COMMAND">ls</tt>, <tt class="COMMAND">cd</tt>, and <tt
class="COMMAND">pwd</tt></a></h2>
<div class="SECT2">
<h3 class="SECT2"><a id="AEN3398" name="AEN3398">10.1.1 <tt
class="COMMAND">ls</tt></a></h3>
<p>This command lists files in a directory. Windows and DOS users will notice its
similarity to the <tt class="COMMAND">dir</tt> command. By itself, <tt
class="COMMAND">ls</tt>(1) will list the files in the current directory. To see what's in
your root directory, you could issue these commands:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">cd /</kbd>
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">ls</kbd>
bin cdr dev home lost+found proc sbin tmp var
boot cdrom etc lib mnt root suncd usr vmlinuz
</pre>
</td>
</tr>
</table>
<p>The problem a lot of people have with that output is that you cannot easily tell what
is a directory and what is a file. Some users prefer that <tt class="COMMAND">ls</tt> add
a type identifier to each listing, like this:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">ls -FC</kbd>
bin/ cdr/ dev/ home/ lost+found/ proc/ sbin/ tmp/ var/
boot/ cdrom/ etc/ lib/ mnt/ root/ suncd/ usr/ vmlinuz
</pre>
</td>
</tr>
</table>
<p>Directories get a slash at the end of the name, executable files get an asterisk at
the end of the name, and so on.</p>
<p><tt class="COMMAND">ls</tt> can also be used to get other statistics on files. For
example, to see the creation dates, owners, and permissions, you would look at a long
listing:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">ls -l</kbd>
drwxr-xr-x 2 root bin 4096 May 7 09:11 bin/
drwxr-xr-x 2 root root 4096 Feb 24 03:55 boot/
drwxr-xr-x 2 root root 4096 Feb 18 01:10 cdr/
drwxr-xr-x 14 root root 6144 Oct 23 18:37 cdrom/
drwxr-xr-x 4 root root 28672 Mar 5 18:01 dev/
drwxr-xr-x 10 root root 4096 Mar 8 03:32 etc/
drwxr-xr-x 8 root root 4096 Mar 8 03:31 home/
drwxr-xr-x 3 root root 4096 Jan 23 21:29 lib/
drwxr-xr-x 2 root root 16384 Nov 1 08:53 lost+found/
drwxr-xr-x 2 root root 4096 Oct 6 12:47 mnt/
dr-xr-xr-x 62 root root 0 Mar 4 15:32 proc/
drwxr-x--x 12 root root 4096 Feb 26 02:06 root/
drwxr-xr-x 2 root bin 4096 Feb 17 02:02 sbin/
drwxr-xr-x 5 root root 2048 Oct 25 10:51 suncd/
drwxrwxrwt 4 root root 487424 Mar 7 20:42 tmp/
drwxr-xr-x 21 root root 4096 Aug 24 03:04 usr/
drwxr-xr-x 18 root root 4096 Mar 8 03:32 var/
</pre>
</td>
</tr>
</table>
<p>Suppose you want to get a listing of the hidden files in the current directory. This
command will do just that:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">ls -a</kbd>
. bin cdrom home mnt sbin usr
.. boot dev lib proc suncd var
.pwrchute_tmp cdr etc lost+found root tmp vmlinuz
</pre>
</td>
</tr>
</table>
<p>Files beginning with a period (called dot files) are hidden when you run <tt
class="COMMAND">ls</tt>. You will only see them if you pass the <var
class="OPTION">-a</var> option.</p>
<p>There are many more options that can be found in the online manual page. Don't forget
that you can combine options that you pass to <tt class="COMMAND">ls</tt>.</p>
</div>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="AEN3436" name="AEN3436">10.1.2 <tt
class="COMMAND">cd</tt></a></h3>
<p>The <tt class="COMMAND">cd</tt> command is used to change working directories. You
simply type <tt class="COMMAND">cd</tt> followed by the path name to change to. Here are
some examples:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
darkstar:~$ <kbd class="USERINPUT">cd /bin</kbd>
darkstar:/bin$ <kbd class="USERINPUT">cd usr</kbd>
bash: cd: usr: No such file or directory
darkstar:/bin$ <kbd class="USERINPUT">cd /usr</kbd>
darkstar:/usr$ <kbd class="USERINPUT">ls</kbd>
bin
darkstar:/usr$ <kbd class="USERINPUT">cd bin</kbd>
darkstar:/usr/bin$
</pre>
</td>
</tr>
</table>
<p>Notice that without the preceding slash, it tries to change to a directory in the
current directory. Also executing <tt class="COMMAND">cd</tt> with no options will move
you to your home directory.</p>
<p>The <tt class="COMMAND">cd</tt> command is not like the other commands. It is a
builtin shell command. Shell builtins are discussed in <a
href="#SHELL-BASH-ENVIRONMENT">Section 8.3.1</a>. This may not make any sense to you
right now. Basically it means there is no man page for this command. Instead, you have to
use the shell help. Like this:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">help cd</kbd>
</pre>
</td>
</tr>
</table>
<p>It will display the options for <tt class="COMMAND">cd</tt> and how to use them.</p>
</div>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="AEN3463" name="AEN3463">10.1.3 <tt
class="COMMAND">pwd</tt></a></h3>
<p>The <tt class="COMMAND">pwd</tt> command is used to show your current location. To use
the <tt class="COMMAND">pwd</tt> command just type <tt class="COMMAND">pwd</tt>. For
example:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">cd /bin</kbd>
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">pwd</kbd>
/bin
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">cd /usr</kbd>
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">cd bin</kbd>
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">pwd</kbd>
/usr/bin
</pre>
</td>
</tr>
</table>
</div>
</div>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="FILE-COMMANDS-PAGERS" name="FILE-COMMANDS-PAGERS">10.2 Pagers:
<tt class="COMMAND">more</tt>, <tt class="COMMAND">less</tt>, and <tt
class="COMMAND">most</tt></a></h2>
<div class="SECT2">
<h3 class="SECT2"><a id="AEN3491" name="AEN3491">10.2.1 <tt
class="COMMAND">more</tt></a></h3>
<p><tt class="COMMAND">more</tt>(1) is what we call a pager utility. Oftentimes the
output of a particular command is too big to fit on one screen. The individual commands
do not know how to fit their output to separate screens. They leave this job to the pager
utility.</p>
<p>The <tt class="COMMAND">more</tt> command breaks the output into individual screens
and waits for you to press the space bar before continuing on to the next screen.
Pressing the enter key will advance the output one line. Here is a good example:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">cd /usr/bin</kbd>
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">ls -l</kbd>
</pre>
</td>
</tr>
</table>
<p>That should scroll for a while. To break up the output screen by screen, just pipe it
through more:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">ls -l | more</kbd>
</pre>
</td>
</tr>
</table>
<p>That is the pipe character (shift backslash). The pipe is short for saying take the
output of <tt class="COMMAND">ls</tt> and feed it into <tt class="COMMAND">more</tt>. You
can pipe just about anything through the <tt class="COMMAND">more</tt> command, not just
<tt class="COMMAND">ls</tt>. Piping is also covered in <a
href="#SHELL-COMMAND-LINE-PIPING">Section 8.2.3</a>.</p>
</div>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="AEN3518" name="AEN3518">10.2.2 <tt
class="COMMAND">less</tt></a></h3>
<p>The <tt class="COMMAND">more</tt> command is quite handy, but often you will find that
you have advanced past the screen you wanted. more does not provide a way to go back. The
<tt class="COMMAND">less</tt>(1) command provides this functionality. It is used in the
same way as the <tt class="COMMAND">more</tt> command, so the previous examples apply
here too. So, <tt class="COMMAND">less</tt> is more than <tt class="COMMAND">more</tt>.
Joost Kremers puts it this way:</p>
<a id="AEN3530" name="AEN3530"></a>
<blockquote class="BLOCKQUOTE">
<p><tt class="COMMAND">less</tt> is more, but more <tt class="COMMAND">more</tt> than <tt
class="COMMAND">more</tt> is, so <tt class="COMMAND">more</tt> is less <tt
class="COMMAND">less</tt>, so use more <tt class="COMMAND">less</tt> if you want less <tt
class="COMMAND">more</tt>.</p>
</blockquote>
</div>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="AEN3539" name="AEN3539">10.2.3 <tt
class="COMMAND">most</tt></a></h3>
<p>Where <tt class="COMMAND">more</tt> and <tt class="COMMAND">less</tt> leave off, <tt
class="COMMAND">most</tt>(1) picks back up. If <tt class="COMMAND">less</tt> is more than
<tt class="COMMAND">more</tt>, <tt class="COMMAND">most</tt> is more than <tt
class="COMMAND">less</tt>. Whereas the other pagers can only display one file at a time,
<tt class="COMMAND">most</tt> is capable of viewing any number of files, as long as each
file's window is at least 2 lines long. <tt class="COMMAND">most</tt> has a lot of
options, check the man page for full details.</p>
</div>
</div>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="FILE-COMMANDS-OUTPUT" name="FILE-COMMANDS-OUTPUT">10.3 Simple
Output: <tt class="COMMAND">cat</tt> and <tt class="COMMAND">echo</tt></a></h2>
<div class="SECT2">
<h3 class="SECT2"><a id="AEN3559" name="AEN3559">10.3.1 <tt
class="COMMAND">cat</tt></a></h3>
<p><tt class="COMMAND">cat</tt>(1) is short for “concatenate”. It was
originally designed to merge text files into one, but can be used for many other
purposes.</p>
<p>To merge two or more files into one, you simply list the files after the <tt
class="COMMAND">cat</tt> command and then redirect the new output to a file. <tt
class="COMMAND">cat</tt> works with standard input and standard output, so you have to
use the shell redirection characters. For example:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd
class="USERINPUT">cat file1 file2 file3 > bigfile</kbd>
</pre>
</td>
</tr>
</table>
<p>This command takes the contents of <tt class="FILENAME">file1</tt>, <tt
class="FILENAME">file2</tt>, and <tt class="FILENAME">file3</tt> and merges it all
together. The new output is sent to standard out.</p>
<p>One can also use <tt class="COMMAND">cat</tt> to display files. Many people <tt
class="COMMAND">cat</tt> text files through the <tt class="COMMAND">more</tt> or <tt
class="COMMAND">less</tt> commands, like this:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">cat file1 | more</kbd>
</pre>
</td>
</tr>
</table>
<p>That will display the <tt class="FILENAME">file1</tt> file and pipe it through the <tt
class="COMMAND">more</tt> command so that you only get one screen at a time.</p>
<p>Another common use for <tt class="COMMAND">cat</tt> is copying files. You can copy any
file around with <tt class="COMMAND">cat</tt>, like this:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">cat /bin/bash > ~/mybash</kbd>
</pre>
</td>
</tr>
</table>
<p>The <tt class="COMMAND">/bin/bash</tt> program is copied to your home directory and
named <tt class="FILENAME">mybash</tt>.</p>
<p><tt class="COMMAND">cat</tt> has many uses and the ones discussed here are just a few.
Since <tt class="COMMAND">cat</tt> makes extensive use of standard input and standard
output, it is ideal for use in shell scripts or part of other complex commands.</p>
</div>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="AEN3603" name="AEN3603">10.3.2 <tt
class="COMMAND">echo</tt></a></h3>
<p>The <tt class="COMMAND">echo</tt>(1) command displays the specified text on the
screen. You specify the string to display after the <tt class="COMMAND">echo</tt>
command. By default <tt class="COMMAND">echo</tt> will display the string and print a
newline character after it. You can pass the <var class="OPTION">-n</var> option to
suppress the printing of the newline. The <var class="OPTION">-e</var> option will cause
<tt class="COMMAND">echo</tt> to search for escape characters in the string and execute
them.</p>
</div>
</div>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="FILE-COMMANDS-CREATION" name="FILE-COMMANDS-CREATION">10.4
Creation: <tt class="COMMAND">touch</tt> and <tt class="COMMAND">mkdir</tt></a></h2>
<div class="SECT2">
<h3 class="SECT2"><a id="AEN3619" name="AEN3619">10.4.1 <tt
class="COMMAND">touch</tt></a></h3>
<p><tt class="COMMAND">touch</tt>(1) is used to change the timestamp on a file. You can
change access timestamps and modification timestamps with this command. If the file
specified does not exist, <tt class="COMMAND">touch</tt> will create a zero length file
with the name specified. To mark a file with the current system time, you would issue
this command:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">ls -al file1</kbd>
-rw-r--r-- 1 root root 9779 Feb 7 21:41 file1
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">touch file1</kbd>
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">ls -al file1</kbd>
-rw-r--r-- 1 root root 9779 Feb 8 09:17 file1
</pre>
</td>
</tr>
</table>
<p>There are several options for <tt class="COMMAND">touch</tt>, including options to
specify which timestamp to modify, the time to use, and many more. The online manual page
discusses these in detail.</p>
</div>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="AEN3639" name="AEN3639">10.4.2 <tt
class="COMMAND">mkdir</tt></a></h3>
<p><tt class="COMMAND">mkdir</tt>(1) will create a new directory. You simply specify the
directory to create when you run mkdir. This example creates the <tt
class="FILENAME">hejaz</tt> directory in the current directory:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">mkdir hejaz</kbd>
</pre>
</td>
</tr>
</table>
<p>You can also specify a path, like this:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">mkdir /usr/local/hejaz</kbd>
</pre>
</td>
</tr>
</table>
<p>The <var class="OPTION">-p</var> option will tell <tt class="COMMAND">mkdir</tt> to
make any parent directories. The above example will fail if <tt
class="COMMAND">/usr/local</tt> does not exist. The <var class="OPTION">-p</var> option
will create <tt class="FILENAME">/usr/local</tt> and <tt
class="FILENAME">/usr/local/hejaz</tt>:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">mkdir -p /usr/local/hejaz</kbd>
</pre>
</td>
</tr>
</table>
</div>
</div>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="FILE-COMMANDS-COPYMOVE" name="FILE-COMMANDS-COPYMOVE">10.5 Copy
and Move</a></h2>
<div class="SECT2">
<h3 class="SECT2"><a id="FILE-COMMANDS-COPYMOVE-CP"
name="FILE-COMMANDS-COPYMOVE-CP">10.5.1 <tt class="COMMAND">cp</tt></a></h3>
<p><tt class="COMMAND">cp</tt>(1) copies files. DOS users will notice its similarity to
the <tt class="COMMAND">copy</tt> command. There are many options for <tt
class="COMMAND">cp</tt> , so you should have a look at the man page before using it.</p>
<p>A common use is to use <tt class="COMMAND">cp</tt> to copy a file from one location to
another. For example:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">cp hejaz /tmp</kbd>
</pre>
</td>
</tr>
</table>
<p>This copies the <tt class="FILENAME">hejaz</tt> file from the current directory to the
<tt class="FILENAME">/tmp</tt> directory.</p>
<p>Many users prefer to keep the timestamps preserved, as in this example:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">cp -a hejaz /tmp</kbd>
</pre>
</td>
</tr>
</table>
<p>This ensures that the timestamps are not modified in the copy.</p>
<p>To recursively copy the contents of a directory to another directory, you would issue
this command:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">cp -R <var
class="REPLACEABLE">mydir</var> /tmp</kbd>
</pre>
</td>
</tr>
</table>
<p>That will copy the <var class="REPLACEABLE">mydir</var> directory to the <tt
class="FILENAME">/tmp</tt> directory.</p>
<p>Also if you wish to copy a directory or a file and keep all it's old permissions and
time stamps and keep it exactly the same use <tt class="COMMAND">cp -p</tt>.</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">ls -l file</kbd>
-rw-r--r-- 1 root vlad 4 Jan 1 15:27 file
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">cp -p file /tmp</kbd>
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">ls -l /tmp/file</kbd>
-rw-r--r-- 1 root vlad 4 Jan 1 15:27 file
</pre>
</td>
</tr>
</table>
<p><tt class="COMMAND">cp</tt> has many more options that are discussed in detail in the
online manual page.</p>
</div>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="AEN3712" name="AEN3712">10.5.2 <tt
class="COMMAND">mv</tt></a></h3>
<p><tt class="COMMAND">mv</tt>(1) moves files from one place to another. Sounds simple
enough doesn't it?</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">mv oldfile /tmp/newfile</kbd>
</pre>
</td>
</tr>
</table>
<p><tt class="COMMAND">mv</tt> has a few useful command line options that are detailed in
the man page. In practice, <tt class="COMMAND">mv</tt> is almost never used with
commandline options.</p>
</div>
</div>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="FILE-COMMANDS-DELETION" name="FILE-COMMANDS-DELETION">10.6
Deletion: <tt class="COMMAND">rm</tt> and <tt class="COMMAND">rmdir</tt></a></h2>
<div class="SECT2">
<h3 class="SECT2"><a id="AEN3733" name="AEN3733">10.6.1 <tt
class="COMMAND">rm</tt></a></h3>
<p><tt class="COMMAND">rm</tt>(1) removes files and directory trees. DOS users will
notice the similarity to both the <tt class="COMMAND">del</tt> and <tt
class="COMMAND">deltree</tt> commands. <tt class="COMMAND">rm</tt> can be very dangerous
if you do not watch yourself. While it is sometimes possible to retrieve a recently
deleted file, it can be complicated (and potentially costly) and is beyond the scope of
this book.</p>
<p>To remove a single file, specify its name when you run rm:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">rm file1</kbd>
</pre>
</td>
</tr>
</table>
<p>If the file has write permissions removed, you may get a permission denied error
message. To force removal of the file no matter what, pass the <tt
class="COMMAND">-f</tt> option, like this:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">rm -f file1</kbd>
</pre>
</td>
</tr>
</table>
<p>To remove an entire directory, you use the <var class="OPTION">-r</var> and <var
class="OPTION">-f</var> options together. This is a good example of how to delete the
entire contents of your hard drive. You really don't want to do this. But here's the
command anyway:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">#</samp> <kbd class="USERINPUT">rm -rf /</kbd>
</pre>
</td>
</tr>
</table>
<p>Be very careful with <tt class="COMMAND">rm</tt>; you can shoot yourself in the foot.
There are several command line options, which are discussed in detail in the online
manual page.</p>
</div>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="AEN3764" name="AEN3764">10.6.2 <tt
class="COMMAND">rmdir</tt></a></h3>
<p><tt class="COMMAND">rmdir</tt>(1) removes directories from the filesystem. The
directory must be empty before it can be removed. The syntax is simply:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">rmdir <<var
class="REPLACEABLE">directory</var>></kbd>
</pre>
</td>
</tr>
</table>
<p>This example will remove the <tt class="FILENAME">hejaz</tt> subdirectory in the
current working directory:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">rmdir hejaz</kbd>
</pre>
</td>
</tr>
</table>
<p>If that directory does not exist, <tt class="COMMAND">rmdir</tt> will tell you. You
can also specify a full path to a directory to remove, as this example shows:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">rmdir /tmp/hejaz</kbd>
</pre>
</td>
</tr>
</table>
<p>That example will try to remove the <tt class="FILENAME">hejaz</tt> directory inside
the <tt class="FILENAME">/tmp</tt> directory.</p>
<p>You can also remove a directory and all of its parent directories by passing the <var
class="OPTION">-p</var> option.</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">rmdir -p /tmp/hejaz</kbd>
</pre>
</td>
</tr>
</table>
<p>This will first try to remove the <tt class="FILENAME">hejaz</tt> directory inside <tt
class="FILENAME">/tmp</tt>. If that is successful, it will try to remove <tt
class="FILENAME">/tmp</tt>. <tt class="COMMAND">rmdir</tt> will continue this until an
error is encountered or the entire tree specified is removed.</p>
</div>
</div>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="FILE-COMMANDS-LINK" name="FILE-COMMANDS-LINK">10.7 Aliasing
files with <tt class="COMMAND">ln</tt></a></h2>
<p><tt class="COMMAND">ln</tt>(1) is used to create links between files. These links can
be either hard links or soft (symbolic) links. The differences between the two kinds of
links were discussed in <a href="#FILESYSTEM-STRUCTURE-LINKS">Section 9.3</a>. If you
wanted to make a symbolic link to the directory <tt class="FILENAME">/var/media/mp3</tt>
and place the link in your home directory, you would do this:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">ln -s /var/media/mp3 ~/mp3</kbd>
</pre>
</td>
</tr>
</table>
<p>The <var class="OPTION">-s</var> option tells <tt class="COMMAND">ln</tt> to make a
symbolic link. The next option is the target of the link, and the final option is what to
call the link. In this case, it will just make a file called <tt
class="FILENAME">mp3</tt> in your home directory that points to <tt
class="FILENAME">/var/media/mp3</tt>. You can call the link itself whatever you want by
just changing the last option.</p>
<p>Making a hard link is just as simple. All you have to do is leave off the <var
class="OPTION">-s</var> option. Hard links may not normally refer to directories or span
file systems, however. To create a hard link <tt class="FILENAME">/usr/bin/email</tt> to
<tt class="FILENAME">/usr/bin/mutt</tt>, simply type the following:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">#</samp> <kbd
class="USERINPUT">ln /usr/bin/mutt /usr/bin/email</kbd>
</pre>
</td>
</tr>
</table>
</div>
</div>
<div class="CHAPTER">
<hr />
<h1><a id="PROCESS-CONTROL" name="PROCESS-CONTROL"></a>Chapter 11 Process Control</h1>
<p>Every program that is running is called a process. These processes range from things
like the X Window System to system programs (daemons) that are started when the computer
boots. Every process runs as a particular user. Processes that are started at boot time
usually run as <tt class="USERNAME">root</tt> or <tt class="USERNAME">nobody</tt>.
Processes that you start will run as you. Processes started as other users will run as
those users.</p>
<p>You have control over all the processes that you start. Additionally, <tt
class="USERNAME">root</tt> has control over all processes on the system, including those
started by other users. Processes can be controlled and monitored through several
programs, as well as some shell commands.</p>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="PROCESS-CONTROL-BACKGROUNDING"
name="PROCESS-CONTROL-BACKGROUNDING">11.1 Backgrounding</a></h2>
<p>Programs started from the command line start up in the foreground. This allows you to
see all the output of the program and interact with it. However, there are several
occasions when you'd like the program to run without taking up your terminal. This is
called running the program in the background, and there are a few ways to do it.</p>
<p>The first way to background a process is by adding an ampersand to the command line
when you start the program. For example, assume you wanted to use the command line mp3
player <tt class="COMMAND">amp</tt> to play a directory full of mp3s, but you needed to
do something else on the same terminal. The following command line would start up amp in
the background:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">amp *.mp3 &</kbd>
</pre>
</td>
</tr>
</table>
<p>The program will run as normal, and you are returned to a prompt.</p>
<p>The other way to background a process is to do so while it is running. First, start up
a program. While it is running, hit <b class="KEYCAP">Control</b>+<b
class="KEYCAP">z</b>. This suspends the process. A suspended process is basically paused.
It momentarily stops running, but can be started up again at any time. Once you have
suspended a process, you are returned to a prompt. You can background the process by
typing:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">bg</kbd>
</pre>
</td>
</tr>
</table>
<p>Now the suspended process is running in the background.</p>
</div>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="PROCESS-CONTROL-FOREGROUNDING"
name="PROCESS-CONTROL-FOREGROUNDING">11.2 Foregrounding</a></h2>
<p>If you need to interact with a backgrounded process, you can bring it back into the
foreground. If you've only got one backgrounded process, you can bring it back by
typing:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">fg</kbd>
</pre>
</td>
</tr>
</table>
<p>If the program is not done running, the program will take control over you terminal
and you will not be returned to a prompt. Sometimes, the program will finish running
while backgrounded. In this instance, you'll get a message like this:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
[1]+ Done /bin/ls $LS_OPTIONS
</pre>
</td>
</tr>
</table>
<p>That tells you that the backgrounded process (in this case <tt class="COMMAND">ls</tt>
- not terribly interesting) has completed.</p>
<p>It is possible to have several processes backgrounded at once. When this happens,
you'll need to know which process you want to bring back to the foreground. Just typing
<tt class="COMMAND">fg</tt> will foreground the process that was last backgrounded. What
if you had a whole list of processes in the background? Luckily, bash includes a command
to list all the processes. It's called <tt class="COMMAND">jobs</tt> and gives output
like so:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">jobs</kbd>
[1] Stopped vim
[2]- Stopped amp
[3]+ Stopped man ps
</pre>
</td>
</tr>
</table>
<p>This shows you a list of all the processes that are backgrounded. As you can see, they
are all stopped. This means that the processes are suspended. The number is a sort of ID
for all the backgrounded processes. The ID with a plus sign beside it (<var
class="LITERAL">man ps</var>) is the process that will be foregrounded if you just type
<tt class="COMMAND">fg</tt>.</p>
<p>If you wanted to foreground <tt class="COMMAND">vim</tt>, you would type:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">fg 1</kbd>
</pre>
</td>
</tr>
</table>
<p>and <tt class="COMMAND">vim</tt> would spring back up to the console. Backgrounding
processes can be very useful if you only have one terminal open over a dialup connection.
You can have several programs running on that one terminal, periodically switching back
and forth between them.</p>
</div>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="PROCESS-CONTROL-PS" name="PROCESS-CONTROL-PS">11.3 <tt
class="COMMAND">ps</tt></a></h2>
<p>So now you know how to switch back and forth between several processes that you've
started from the command line. And you also know that there are lots of processes running
all the time. So how do you list all of these programs? Well, you make use of the <tt
class="COMMAND">ps</tt>(1) command. This command has a lot of options, so we'll only
cover the most important ones here. For a complete listing, see the man page for ps. Man
pages are covered in-depth in <a href="#HELP-SYSTEM-MAN">Section 2.1.1</a>.</p>
<p>Simply typing <tt class="COMMAND">ps</tt> will get you a listing of the programs
running on your terminal. This incudes the foreground processes (which include whatever
shell you are using, and of course, <tt class="COMMAND">ps</tt> itself). Also listed are
backgrounded processes you may have running. Many times, that will be a very short
listing:</p>
<div class="FIGURE"><a id="FIG-PROCESS-CONTROL-PS-SHORT"
name="FIG-PROCESS-CONTROL-PS-SHORT"></a>
<p><b>Figure 11-1. Basic <tt class="COMMAND">ps</tt> output</b></p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">ps</kbd>
PID TTY TIME CMD
7923 ttyp0 00:00:00 bash
8059 ttyp0 00:00:00 ps
</pre>
</td>
</tr>
</table>
</div>
<p>Even though this is not a lot of processes, the information is very typical. You'll
get the same columns using regular ps no matter how many processes are running. So what
does it all mean?</p>
<p>Well, the <var class="LITERAL">PID</var> is the <span class="emphasis"><i
class="EMPHASIS">process ID</i></span>. All running processes are given a unique
identifier which ranges between 1 and 32767. Each process is assigned the next free PID.
When a process quits (or is killed, as you will see in the next section), it gives up its
PID. When the max PID is reached, the next free one will wrap back around to the lowest
free one.</p>
<p>The <var class="LITERAL">TTY</var> column indicates which terminal the process is
running on. Doing a plain <tt class="COMMAND">ps</tt> will only list all the programs
running on the current terminal, so all the processes give the same information in the
TTY column. As you can see, both processes listed are running on <tt
class="FILENAME">ttyp0</tt>. This indicates that they are either running remotely or from
an X terminal of some variety.</p>
<p>The <var class="LITERAL">TIME</var> column indicated how much CPU time the process has
been running. This is different from the actual amount of time that a process runs.
Remember that Linux is a multitasking operating system. There are many processes running
all the time, and these processes each get a small portion of the processor's time. So,
the TIME column should show much less time for each process than it actually takes to
run. If you see more than several minutes in the TIME column, it could mean that
something is wrong.</p>
<p>Finally, the <var class="LITERAL">CMD</var> column shows what the program actually is.
It only lists the base name of the program, not any command line options or similar
information. To get that information, you'll need to use one of the many options to <tt
class="COMMAND">ps</tt>. We'll discuss that shortly.</p>
<p>You can get a complete listing of the processes running on your system using the right
combination of options. This will probably result in a long listing of processes
(fifty-five on my laptop as I write this sentence), so I'll abbreviate the output:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">ps -ax</kbd>
PID TTY STAT TIME COMMAND
1 ? S 0:03 init [3]
2 ? SW 0:13 [kflushd]
3 ? SW 0:14 [kupdate]
4 ? SW 0:00 [kpiod]
5 ? SW 0:17 [kswapd]
11 ? S 0:00 /sbin/kerneld
30 ? SW 0:01 [cardmgr]
50 ? S 0:00 /sbin/rpc.portmap
54 ? S 0:00 /usr/sbin/syslogd
57 ? S 0:00 /usr/sbin/klogd -c 3
59 ? S 0:00 /usr/sbin/inetd
61 ? S 0:04 /usr/local/sbin/sshd
63 ? S 0:00 /usr/sbin/rpc.mountd
65 ? S 0:00 /usr/sbin/rpc.nfsd
67 ? S 0:00 /usr/sbin/crond -l10
69 ? S 0:00 /usr/sbin/atd -b 15 -l 1
77 ? S 0:00 /usr/sbin/apmd
79 ? S 0:01 gpm -m /dev/mouse -t ps2
94 ? S 0:00 /usr/sbin/automount /auto file /etc/auto.misc
106 tty1 S 0:08 -bash
108 tty3 SW 0:00 [agetty]
109 tty4 SW 0:00 [agetty]
110 tty5 SW 0:00 [agetty]
111 tty6 SW 0:00 [agetty]
[output cut]
</pre>
</td>
</tr>
</table>
<p>Most of these processes are started at boot time on most systems. I've made a few
modifications to my system, so your mileage will most likely vary. However, you will see
most of these processes on your system too. As you can see, these options display command
line options to the running processes. Recently, a kernel vulnerability in <tt
class="COMMAND">ptrace</tt> facilitated a fix which no longer shows command line options
for many running processes. These are now listed in brackets like PIDs 108 through 110.
It also brings up a few more columns and some other interesting output.</p>
<p>First, you'll notice that most of these processes are listed as running on tty
“?”. Those are not attached to any particular terminal. This is most common
with daemons, which are processes which run without attaching to any particular terminal.
Common daemons are sendmail, BIND, apache, and NFS. They typically listen for some
request from a client, and return information to it upon request.</p>
<p>Second, there is a new column: <var class="LITERAL">STAT</var>. It shows the status of
the process. <var class="LITERAL">S</var> stands for sleeping: the process is waiting for
something to happen. <var class="LITERAL">Z</var> stands for a zombied process. A zombied
processes is one whose parent has died, leaving the child processes behind. This is not a
good thing. <var class="LITERAL">D</var> stands for a process that has entered an
uninterruptible sleep. Often, these processes refuse to die even when passed a SIGKILL.
You can read more about SIGKILL later in the next section on <tt
class="COMMAND">kill</tt> . W stands for paging. A dead process is marked with an <var
class="LITERAL">X</var>. A process marked <var class="LITERAL">T</var> is traced, or
stopped. <var class="LITERAL">R</var> means that the process is runable.</p>
<p>If you want to see even more information about the running processes, try this
out:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">ps -aux</kbd>
USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND
root 1 0.0 0.0 344 80 ? S Mar02 0:03 init [3]
root 2 0.0 0.0 0 0 ? SW Mar02 0:13 [kflushd]
root 3 0.0 0.0 0 0 ? SW Mar02 0:14 [kupdate]
root 4 0.0 0.0 0 0 ? SW Mar02 0:00 [kpiod]
root 5 0.0 0.0 0 0 ? SW Mar02 0:17 [kswapd]
root 11 0.0 0.0 1044 44 ? S Mar02 0:00 /sbin/kerneld
root 30 0.0 0.0 1160 0 ? SW Mar02 0:01 [cardmgr]
bin 50 0.0 0.0 1076 120 ? S Mar02 0:00 /sbin/rpc.port
root 54 0.0 0.1 1360 192 ? S Mar02 0:00 /usr/sbin/sysl
root 57 0.0 0.1 1276 152 ? S Mar02 0:00 /usr/sbin/klog
root 59 0.0 0.0 1332 60 ? S Mar02 0:00 /usr/sbin/inet
root 61 0.0 0.2 1540 312 ? S Mar02 0:04 /usr/local/sbi
root 63 0.0 0.0 1796 72 ? S Mar02 0:00 /usr/sbin/rpc.
root 65 0.0 0.0 1812 68 ? S Mar02 0:00 /usr/sbin/rpc.
root 67 0.0 0.2 1172 260 ? S Mar02 0:00 /usr/sbin/cron
root 77 0.0 0.2 1048 316 ? S Mar02 0:00 /usr/sbin/apmd
root 79 0.0 0.1 1100 152 ? S Mar02 0:01 gpm
root 94 0.0 0.2 1396 280 ? S Mar02 0:00 /usr/sbin/auto
chris 106 0.0 0.5 1820 680 tty1 S Mar02 0:08 -bash
root 108 0.0 0.0 1048 0 tty3 SW Mar02 0:00 [agetty]
root 109 0.0 0.0 1048 0 tty4 SW Mar02 0:00 [agetty]
root 110 0.0 0.0 1048 0 tty5 SW Mar02 0:00 [agetty]
root 111 0.0 0.0 1048 0 tty6 SW Mar02 0:00 [agetty]
[output cut]
</pre>
</td>
</tr>
</table>
<p>That's a whole lot of information. Basically, it adds information including what user
started the process, how much of the system resources the process is using (the %CPU,
%MEM, VSZ, and RSS columns), and on what date the process was started. Obviously, that's
a lot of information that could come in handy for a system administrator. It also brings
up another point: the information now goes off the edge of the screen so that you cannot
see it all. The <var class="OPTION">-w</var> option will force <tt
class="COMMAND">ps</tt> to wrap long lines.</p>
<p>It's not terribly pretty, but it does the job. You've now got the complete listings
for each process. There's even more information that you can display about each process.
Check out the very in-depth man page for <tt class="COMMAND">ps</tt>. However, the
options shown above are the most popular ones and will be the ones you need to use the
most often.</p>
</div>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="PROCESS-CONTROL-KILL" name="PROCESS-CONTROL-KILL">11.4 <tt
class="COMMAND">kill</tt></a></h2>
<p>On occasion, programs misbehave and you'll need to put them back in line. The program
for this kind of administration is called <tt class="COMMAND">kill</tt>(1), and it can be
used for manipulating processes in several ways. The most obvious use of <tt
class="COMMAND">kill</tt> is to kill off a process. You'll need to do this if a program
has run away and is using up lots of system resources, or if you're just sick of it
running.</p>
<p>In order to kill off a process, you'll need to know its PID or its name. To get the
PID, use the <tt class="COMMAND">ps</tt> command as was discussed in the last section.
For example, to kill off process 4747, you'd issue the following:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">kill 4747</kbd>
</pre>
</td>
</tr>
</table>
<p>Note that you'll have to be the owner of the process in order to kill it. This is a
security feature. If you were allowed to kill off processes started by other users, it
would be possible to do all sorts of malicious things. Of course, <tt
class="USERNAME">root</tt> can kill off any process on the system.</p>
<p>There's another variety of the <tt class="COMMAND">kill</tt> command called <tt
class="COMMAND">killall</tt>(1). This program does exactly what it says: it kills all the
running processes that have a certain name. If you wanted to kill off all the running <tt
class="COMMAND">vim</tt> processes, you could type the following command:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">killall vim</kbd>
</pre>
</td>
</tr>
</table>
<p>Any and all <tt class="COMMAND">vim</tt> processes you have running will die off.
Doing this as <tt class="USERNAME">root</tt> would kill off all the <tt
class="COMMAND">vim</tt> processes running for all users. This brings up an interesting
way to kick everyone (including yourself) off the system:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">#</samp> <kbd class="USERINPUT">killall bash</kbd>
</pre>
</td>
</tr>
</table>
<p>Sometimes a regular kill doesn't get the job done. Certain processes will not die with
a kill. You'll need to use a more potent form. If that pesky PID 4747 wasn't responding
to your kill request, you could do the following:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">kill -9 4747</kbd>
</pre>
</td>
</tr>
</table>
<p>That will almost certainly cause process 4747 to die. You can do the same thing with
<tt class="COMMAND">killall</tt>. What this is doing is sending a different signal to the
process. A regular <tt class="COMMAND">kill</tt> sends a <var
class="LITERAL">SIGTERM</var> (terminate) signal to the process, which tells it to finish
what it's doing, clean up, and exit. <tt class="COMMAND">kill -9</tt> sends a <var
class="LITERAL">SIGKILL</var> (kill) signal to the process, which essentially drops it.
The process is not allowed to clean-up, and sometimes bad things like data corruption
could occur by killing something with a <var class="LITERAL">SIGKILL</var>. There's a
whole list of signals at your disposal. You can get a listing of signals by typing the
following:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">kill -l</kbd>
1) SIGHUP 2) SIGINT 3) SIGQUIT 4) SIGILL
5) SIGTRAP 6) SIGABRT 7) SIGBUS 8) SIGFPE
9) SIGKILL 10) SIGUSR1 11) SIGSEGV 12) SIGUSR2
13) SIGPIPE 14) SIGALRM 15) SIGTERM 17) SIGCHLD
18) SIGCONT 19) SIGSTOP 20) SIGTSTP 21) SIGTTIN
22) SIGTTOU 23) SIGURG 24) SIGXCPU 25) SIGXFSZ
26) SIGVTALRM 27) SIGPROF 28) SIGWINCH 29) SIGIO
30) SIGPWR
</pre>
</td>
</tr>
</table>
<p>The number must be used for <tt class="COMMAND">kill</tt>, while the name minus the
leading “SIG” can be used with <tt class="COMMAND">killall</tt>. Here's
another example:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">killall -KILL vim</kbd>
</pre>
</td>
</tr>
</table>
<p>A final use of <tt class="COMMAND">kill</tt> is to restart a process. Sending a <var
class="LITERAL">SIGHUP</var> will cause most processes to re-read their configuration
files. This is especially helpful for telling system processes to re-read their config
files after editing.</p>
</div>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="PROCESS-CONTROL-TOP" name="PROCESS-CONTROL-TOP">11.5 <tt
class="COMMAND">top</tt></a></h2>
<p>Finally, there's a command you can use to display updating information about the
processes running on the system. This command is called <tt class="COMMAND">top</tt>(1),
and is started like so:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">top</kbd>
</pre>
</td>
</tr>
</table>
<p>This will display a full screen of information about the processes running on the
system, as well as some overall information about the system. This includes load average,
number of processes, the CPU status, free memory information, and details about processes
including PID, user, priority, CPU and memory usage information, running time, and
program name.</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
6:47pm up 1 day, 18:01, 1 user, load average: 0.02, 0.07, 0.02
61 processes: 59 sleeping, 2 running, 0 zombie, 0 stopped
CPU states: 2.8% user, 3.1% system, 0.0% nice, 93.9% idle
Mem: 257992K av, 249672K used, 8320K free, 51628K shrd, 78248K buff
Swap: 32764K av, 136K used, 32628K free, 82600K cached
<span class="emphasis"><i
class="EMPHASIS">PID USER PRI NI SIZE RSS SHARE STAT LIB %CPU %MEM TIME COMMAND</i></span>
112 root 12 0 19376 18M 2468 R 0 3.7 7.5 55:53 X
4947 david 15 0 2136 2136 1748 S 0 2.3 0.8 0:00 screenshot
3398 david 7 0 20544 20M 3000 S 0 1.5 7.9 0:14 gimp
4946 root 12 0 1040 1040 836 R 0 1.5 0.4 0:00 top
121 david 4 0 796 796 644 S 0 1.1 0.3 25:37 wmSMPmon
115 david 3 0 2180 2180 1452 S 0 0.3 0.8 1:35 wmaker
4948 david 16 0 776 776 648 S 0 0.3 0.3 0:00 xwd
1 root 1 0 176 176 148 S 0 0.1 0.0 0:13 init
189 david 1 0 6256 6156 4352 S 0 0.1 2.4 3:16 licq
4734 david 0 0 1164 1164 916 S 0 0.1 0.4 0:00 rxvt
2 root 0 0 0 0 0 SW 0 0.0 0.0 0:08 kflushd
3 root 0 0 0 0 0 SW 0 0.0 0.0 0:06 kupdate
4 root 0 0 0 0 0 SW 0 0.0 0.0 0:00 kpiod
5 root 0 0 0 0 0 SW 0 0.0 0.0 0:04 kswapd
31 root 0 0 340 340 248 S 0 0.0 0.1 0:00 kerneld
51 root 0 0 48 48 32 S 0 0.0 0.0 0:00 dhcpcd
53 bin 0 0 316 316 236 S 0 0.0 0.1 0:00 rpc.portmap
57 root 0 0 588 588 488 S 0 0.0 0.2 0:01 syslogd
</pre>
</td>
</tr>
</table>
<p>It's called <tt class="COMMAND">top</tt> because the most CPU intensive programs will
be listed at the top. An interesting note is that top will be listed first on most
inactive (and some active) systems because of its CPU utilization. However, <tt
class="COMMAND">top</tt> is quite useful for determining what program is misbehaving and
needs to be killed off.</p>
<p>But suppose you only want a list of your own processes, or the processes of some other
user. The processes you want to see might not be among the most CPU intensive programs
currently running. The <var class="OPTION">-u</var> option allows you to specify a
username or UID and monitor only those processes owned by that UID.</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">top -u alan</kbd>
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
3622 alan 13 0 11012 10m 6956 S 1.0 2.1 0:03.66 gnome-terminal
3739 alan 13 0 1012 1012 804 R 0.3 0.2 0:00.06 top
3518 alan 9 0 1312 1312 1032 S 0.0 0.3 0:00.09 bash
3529 alan 9 0 984 984 848 S 0.0 0.2 0:00.00 startx
3544 alan 9 0 640 640 568 S 0.0 0.1 0:00.00 xinit
3548 alan 9 0 8324 8320 6044 S 0.0 1.6 0:00.30 gnome-session
3551 alan 9 0 7084 7084 1968 S 0.0 1.4 0:00.50 gconfd-2
3553 alan 9 0 2232 2232 380 S 0.0 0.4 0:00.05 esd
3555 alan 9 0 2552 2552 1948 S 0.0 0.5 0:00.10 bonobo-activati
3557 alan 9 0 2740 2740 2224 S 0.0 0.5 0:00.05 gnome-smproxy
3559 alan 9 0 6496 6492 5004 S 0.0 1.3 0:00.31 gnome-settings-
3565 alan 9 0 1740 1740 1440 S 0.0 0.3 0:00.28 xscreensaver
3568 alan 9 0 7052 7052 4960 S 0.0 1.4 0:02.28 metacity
3572 alan 9 0 11412 11m 7992 S 0.0 2.2 0:01.58 gnome-panel
3574 alan 9 0 12148 11m 8780 S 0.0 2.4 0:00.64 nautilus
3575 alan 9 0 12148 11m 8780 S 0.0 2.4 0:00.00 nautilus
3576 alan 9 0 12148 11m 8780 S 0.0 2.4 0:00.00 nautilus
</pre>
</td>
</tr>
</table>
<p>As you can see, I'm currently running <tt class="COMMAND">X</tt>, <tt
class="COMMAND">top</tt>, a <tt class="COMMAND">gnome-terminal</tt> (in which I'm writing
this) and many other X-related processes which take up the most CPU time for me. This is
a good way to monitor how hard your users are working your system.</p>
<p><tt class="COMMAND">top</tt> also supports monitoring processes by their PID, ignoring
idle and zombied processes, and many other options. The best place to get a handle on
these options is the man page for <tt class="COMMAND">top</tt>.</p>
</div>
</div>
<div class="CHAPTER">
<hr />
<h1><a id="ESSENTIAL-SYSADMIN" name="ESSENTIAL-SYSADMIN"></a>Chapter 12 Essential System
Administration</h1>
<p>Whoa whoa whoa whoa whoa.... I know what you're thinking. “I'm not a system
administrator! I don't even want to be a system administrator!”</p>
<p>Fact is, you are the administrator of any computers for which you have the <tt
class="USERNAME">root</tt> password. This might be your desktop box with one or two
users, or it might be a big server with several hundred. Regardless, you'll need to know
how to manage users, and how to shut down the system safely. These tasks seem simple, but
they have some quirks to keep in mind.</p>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="ESSENTIAL-SYSADMIN-USERS" name="ESSENTIAL-SYSADMIN-USERS">12.1
Users and Groups</a></h2>
<p>As mentioned in <a href="#SHELL">Chapter 8</a>, you shouldn't normally use your system
logged in as <tt class="USERNAME">root</tt>. Instead, you should create a normal user
account for everyday use, and use the root account only for system administration tasks.
To create a user, you can either use the tools supplied with Slackware, or you can edit
the password files by hand.</p>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="ESSENTIAL-SYSADMIN-USERS-SCRIPTS"
name="ESSENTIAL-SYSADMIN-USERS-SCRIPTS">12.1.1 Supplied Scripts</a></h3>
<p>The easiest way to manage users and groups is with the supplied scripts and programs.
Slackware includes the programs <tt class="COMMAND">adduser</tt>, <tt
class="COMMAND">userdel</tt>(8), <tt class="COMMAND">chfn</tt>(1), <tt
class="COMMAND">chsh</tt>(1), and <tt class="COMMAND">passwd</tt>(1) for dealing with
users. The commands <tt class="COMMAND">groupadd</tt>(8), <tt
class="COMMAND">groupdel</tt>(8), and <tt class="COMMAND">groupmod</tt>(8) are for
dealing with groups. With the exception of <tt class="COMMAND">chfn</tt>, <tt
class="COMMAND">chsh</tt>, and <tt class="COMMAND">passwd</tt>, these programs are
generally only run as <tt class="USERNAME">root</tt>, and are therefore located in <tt
class="FILENAME">/usr/sbin</tt>. <tt class="COMMAND">chfn</tt>, <tt
class="COMMAND">chsh</tt>, and <tt class="COMMAND">passwd</tt> can be run by anyone, and
are located in <tt class="FILENAME">/usr/bin</tt>.</p>
<p>Users can be added with the <tt class="COMMAND">adduser</tt> program. We'll start out
by going through the whole procedure, showing all the questions that are asked and a
brief description of what everything means. The default answer is in the brackets, and
can be chosen for almost all the questions, unless you really want to change
something.</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">#</samp> <kbd class="USERINPUT">adduser</kbd>
Login name for new user []: jellyd
</pre>
</td>
</tr>
</table>
<p>This is the name that the user will use to login. Traditionally, login names are eight
characters or fewer, and all lowercase characters. (You may use more than eight
characters, or use digits, but avoid doing so unless you have a fairly important
reason.)</p>
<p>You can also provide the login name as an argument on the command line:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">#</samp> <kbd class="USERINPUT">adduser jellyd</kbd>
</pre>
</td>
</tr>
</table>
<p>In either case, after providing the login name, adduser will prompt for the user
ID:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
User ID ('UID') [ defaults to next available ]:
</pre>
</td>
</tr>
</table>
<p>The user ID (UID) is how ownerships are really determined in Linux. Each user has a
unique number, starting at 1000 in Slackware. You can pick a UID for the new user, or you
can just let adduser assign the user the next free one.</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
Initial group [users]:
</pre>
</td>
</tr>
</table>
<p>All users are placed into the <tt class="USERNAME">users</tt> group by default. You
might want to place the new user into a different group, but it is not recommended unless
you know what you're doing.</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
Additional groups (comma separated) []:
</pre>
</td>
</tr>
</table>
<p>This question allows you to place the new user into additional groups. It is possible
for a user to be in several groups at the same time. This is useful if you have
established groups for things like modifying web site files, playing games, and so on.
For example, some sites define group <tt class="USERNAME">wheel</tt> as the only group
that can use the <tt class="COMMAND">su</tt> command. Or, a default Slackware
installation uses the <tt class="USERNAME">sys</tt> group for users authorized to play
sounds through the internal sound card.</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
Home directory [/home/jellyd]
</pre>
</td>
</tr>
</table>
<p>Home directories default to being placed under <tt class="FILENAME">/home</tt>. If you
run a very large system, it's possible that you have moved the home directories to a
different location (or to many locations). This step allows you to specify where the
user's home directory will be.</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
Shell [ /bin/bash ]
</pre>
</td>
</tr>
</table>
<p><tt class="COMMAND">bash</tt> is the default shell for Slackware Linux, and will be
fine for most people. If your new user comes from a Unix background, they may be familiar
with a different shell. You can change their shell now, or they can change it themselves
later using the <tt class="COMMAND">chsh</tt> command.</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
Expiry date (YYYY-MM-DD) []:
</pre>
</td>
</tr>
</table>
<p>Accounts can be set up to expire on a specified date. By default, there is no
expiration date. You can change that, if you'd like. This option might be useful for
people running an ISP who might want to make an account expire upon a certain date,
unless they receive the next year's payment.</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
New account will be created as follows:
---------------------------------------
Login name: jellyd
UID: [ Next available ]
Initial group: users
Additional groups: [ None ]
Home directory: /home/jellyd
Shell: /bin/bash
Expiry date: [ Never ]
</pre>
</td>
</tr>
</table>
<p>This is it... if you want to bail out, hit <b class="KEYCAP">Control</b>+<b
class="KEYCAP">C</b>. Otherwise, press <kbd class="USERINPUT">ENTER</kbd> to go ahead and
make the account.</p>
<p>You now see all the information that you've entered about the new account and are
given the opportunity to abort the account creation. If you entered something
incorrectly, you should hit <b class="KEYCAP">Control</b>+<b class="KEYCAP">C</b> and
start over. Otherwise, you can hit <kbd class="USERINPUT">enter</kbd> and the account
will be made.</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
Creating new account...
Changing the user information for jellyd
Enter the new value, or press return for the default
Full Name []: Jeremy
Room Number []: Smith 130
Work Phone []:
Home Phone []:
Other []:
</pre>
</td>
</tr>
</table>
<p>All of this information is optional. You don't have to enter any of this if you don't
want to, and the user can change it at any time using <tt class="COMMAND">chfn</tt>.
However, you might find it helpful to enter at least the full name and a phone number, in
case you need to get in touch with the person later.</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
Changing password for jellyd
Enter the new password (minimum of 5, maximum of 127 characters)
Please use a combination of upper and lower case letters and numbers.
New password:
Re-enter new password:
Password changed.
Account setup complete.
</pre>
</td>
</tr>
</table>
<p>You'll have to enter a password for the new user. Generally, if the new user is not
physically present at this point, you'll just pick some default password and tell the
user to change it to something more secure.</p>
<div class="NOTE">
<table class="NOTE" width="100%" border="0">
<tr>
<td width="25" align="CENTER" valign="TOP"><img src="./imagelib/admon/note.png"
hspace="5" alt="Note" /></td>
<td align="LEFT" valign="TOP">
<p><span class="emphasis"><i class="EMPHASIS">Choosing a Password</i></span>: Having a
secure password is the first line of defense against getting cracked. You do not want to
have an easily guessed password, because that makes it easier for someone to break into
your system. Ideally, a secure password would be a random string of characters, including
upper and lowercase letters, numbers, and random characters. (A tab character might not
be a wise choice, depending on what kinds of computers you'll be logging in from.) There
are many software packages that can generate random passwords for you; search the
Internet for these utilities.</p>
<p>In general, just use common sense: don't pick a password that is someone's birthday, a
common phrase, something found on your desk, or anything that is easily associated with
you. A password like “secure1” or any other password you see in print or
online is also bad.</p>
</td>
</tr>
</table>
</div>
<p>Removing users is not difficult at all. Just run <tt class="COMMAND">userdel</tt> with
the name of the account to remove. You should verify that the user is not logged in, and
that no processes are running as that user. Also, remember that once you've deleted the
user, all of that user's password information is gone permanently.</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">#</samp> <kbd class="USERINPUT">userdel jellyd</kbd>
</pre>
</td>
</tr>
</table>
<p>This command removes that annoying <tt class="USERNAME">jellyd</tt> user from your
system. Good riddance! :) The user is removed from the <tt
class="FILENAME">/etc/passwd</tt>, <tt class="FILENAME">/etc/shadow</tt>, and <tt
class="FILENAME">/etc/group</tt> files, but doesn't remove the user's home directory.</p>
<p>If you'd wanted to remove the home directory as well, you would instead use this
command:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">#</samp> <kbd class="USERINPUT">userdel -r jellyd</kbd>
</pre>
</td>
</tr>
</table>
<p>Temporarily disabling an account will be covered in the next section on passwords,
since a temporary change involves changing the user's password. Changing other account
information is covered in <a href="#ESSENTIAL-SYSADMIN-USERS-CHANGING">Section
12.1.3</a>.</p>
<p>The programs to add and remove groups are very simple. <tt
class="COMMAND">groupadd</tt> will just add another entry to the <tt
class="FILENAME">/etc/group</tt> file with a unique group ID, while <tt
class="COMMAND">groupdel</tt> will remove the specified group. It is up to you to edit
<tt class="FILENAME">/etc/group</tt> to add users to a specific group. For example, to
add a group called <tt class="USERNAME">cvs</tt>:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">#</samp> <kbd class="USERINPUT">groupadd cvs</kbd>
</pre>
</td>
</tr>
</table>
<p>And to remove it:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">#</samp> <kbd class="USERINPUT">groupdel cvs</kbd>
</pre>
</td>
</tr>
</table>
</div>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="ESSENTIAL-SYSADMIN-USERS-PASSWDS"
name="ESSENTIAL-SYSADMIN-USERS-PASSWDS">12.1.2 Changing Passwords</a></h3>
<p>The <tt class="COMMAND">passwd</tt> program changes passwords by modifying the <tt
class="FILENAME">/etc/shadow</tt> file. This file holds all the passwords for the system
in an encrypted format. In order to change your own password, you would type:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">passwd</kbd>
Changing password for chris
Old password:
Enter the new password (minumum of 5, maximum of 127 characters)
Please use a combination of upper and lower case letters and numbers.
New password:
</pre>
</td>
</tr>
</table>
<p>As you can see, you are prompted to enter your old password. It won't appear on the
screen as you type it, just like when you log in. Then, you are prompted to enter the new
password. <tt class="COMMAND">passwd</tt> performs a lot of checks on your new password,
and it will complain if your new password doesn't pass its checks. You can ignore its
warnings if you want. You will be prompted to enter your new password a second time for
confirmation.</p>
<p>If you are <tt class="USERNAME">root</tt>, you can also change another user's
password:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">#</samp> <kbd class="USERINPUT">passwd ted</kbd>
</pre>
</td>
</tr>
</table>
<p>You will then have to go through the same procedure as above, except that you won't
have to enter the user's old password. (One of the many benefits of being <tt
class="USERNAME">root</tt>...)</p>
<p>If needed, you can also temporarily disable an account, and reenable it at a later
time if needed. Both disabling an account and reenabling an account can be done with <tt
class="COMMAND">passwd</tt>. To disable an account, do the following as <tt
class="USERNAME">root</tt>:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">#</samp> <kbd class="USERINPUT">passwd -l david</kbd>
</pre>
</td>
</tr>
</table>
<p>This will change david's password to something that can never match any encrypted
value. You would reenable the account by using:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">#</samp> <kbd class="USERINPUT">passwd -u david</kbd>
</pre>
</td>
</tr>
</table>
<p>Now, david's account is back to normal. Disabling an account might be useful if the
user doesn't play by the rules you've set up on your system, or if they've exported a
very large copy of <tt class="COMMAND">xeyes</tt>(1) to your X desktop.</p>
</div>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="ESSENTIAL-SYSADMIN-USERS-CHANGING"
name="ESSENTIAL-SYSADMIN-USERS-CHANGING">12.1.3 Changing User Information</a></h3>
<p>There are two pieces of information that users can change at any time: their shell and
their finger information. Slackware Linux uses <tt class="COMMAND">chsh</tt> (change
shell) and <tt class="COMMAND">chfn</tt> (change finger) to modify these values.</p>
<p>A user can pick any shell that is listed in the <tt class="FILENAME">/etc/shells</tt>
file. For most people, <tt class="COMMAND">/bin/bash</tt> will do just fine. Others might
be familiar with a shell found on their system at work or school and want to use what
they already know. To change your shell, use <tt class="COMMAND">chsh</tt>:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">chsh</kbd>
Password:
Changing the login shell for chris
Enter the new value, or press return for the default
Login Shell [/bin/bash]:
</pre>
</td>
</tr>
</table>
<p>After entering your password, enter the full path to the new shell. Make sure that
it's listed in the <tt class="FILENAME">/etc/shells</tt>(5) file first. The <tt
class="USERNAME">root</tt> user can also change any user's shell by running <tt
class="COMMAND">chsh</tt> with a username as the argument.</p>
<p>The finger information is the optional information such as your full name, phone
numbers, and room number. This can be changed using <tt class="COMMAND">chfn</tt>, and
follows the same procedure as it did during account creation. As usual, <tt
class="USERNAME">root</tt> can change anyone's finger information.</p>
</div>
</div>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="ESSENTIAL-SYSADMIN-HARDUSERS"
name="ESSENTIAL-SYSADMIN-HARDUSERS">12.2 Users and Groups, the Hard Way</a></h2>
<p>Of course, it is possible to add, modify, and remove users and groups without using
the scripts and programs that come with Slackware. It's not really difficult, although
after reading this process, you'll probably find it much easier to use the scripts.
However, it's important to know how your password information is actually stored, in case
you ever need to recover this information and don't have the Slackware tools
available.</p>
<p>First, we'll add a new user to the <tt class="FILENAME">/etc/passwd</tt>(5), <tt
class="FILENAME">/etc/shadow</tt>(5), and <tt class="FILENAME">/etc/group</tt>(5) files.
The <tt class="FILENAME">passwd</tt> file holds some information about the users on your
system, but (strangely enough) not their passwords. This was once the case, but was
halted long ago for security reasons. The passwd file must be readable by all users, but
you don't want encrypted passwords world-readable, as would-be intruders can use the
encrypted passwords as a starting point for decrypting a user's password. Instead, the
encrypted passwords are kept in the shadow file, which is only readable by root, and
everyone's password is entered into the <tt class="FILENAME">passwd</tt> file simply as
“<var class="LITERAL">x</var>”. The <tt class="FILENAME">group</tt> file
lists all the groups and who is in each.</p>
<p>You can use the <tt class="COMMAND">vipw</tt> command to edit the <tt
class="FILENAME">/etc/passwd</tt> file safely, and the <tt class="COMMAND">vigr</tt>
command to edit the <tt class="FILENAME">/etc/group</tt> file safely. Use <tt
class="COMMAND">vipw -s</tt> to edit the <tt class="FILENAME">/etc/shadow</tt> file
safely. (“Safely” in this context means someone else won't be able to modify
the file you're editing at the moment. If you're the only administrator of your system,
you're probably safe, but it's best to get into good habits from the start.)</p>
<p>Let's examine the <tt class="FILENAME">/etc/passwd</tt> file and look at how to add a
new user. A typical entry in <tt class="FILENAME">passwd</tt> looks like this:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="PROGRAMLISTING">
chris:x:1000:100:Chris Lumens,Room 2,,:/home/chris:/bin/bash
</pre>
</td>
</tr>
</table>
<p>Each line is an entry for one user, and fields on each line are separated by a colon.
The fields are the login name, encrypted password (“<var
class="LITERAL">x</var>” for everyone on a Slackware system, since Slackware uses
shadow passwords), user ID, group ID, the optional finger information (separated by
commas), home directory, and shell. To add a new user by hand, add a new line at the end
of the file, filling in the appropriate information.</p>
<p>The information you add needs to meet some requirements, or your new user may have
problems logging in. First, make sure that the password field is an <var
class="LITERAL">x</var>, and that both the user name and user ID is unique. Assign the
user a group, either 100 (the “users” group in Slackware) or your default
group (use its number, not its name). Give the user a valid home directory (which you'll
create later) and shell (remember, valid shells are listed in <tt
class="FILENAME">/etc/shells</tt>).</p>
<p>Next, we'll need to add an entry in the /etc/shadow file, which holds the encrypted
passwords. A typical entry looks like this:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="PROGRAMLISTING">
chris:$1$w9bsw/N9$uwLr2bRER6YyBS.CAEp7R.:11055:0:99999:7:::
</pre>
</td>
</tr>
</table>
<p>Again, each line is an entry for one person, with each field delimited by a colon. The
fields are (in order) login name, encrypted password, days since the Epoch (January 1,
1970) that the password was last changed, days before the password may be changed, days
after which the password must be changed, days before password expiration that the user
is notified, days after expiration that the account is disabled, days since the Epoch
that the account is disabled, and a reserved field.</p>
<p>As you can see, most of that is for account expiration information. If you aren't
using expiration information, you only need to fill in a few fields with some special
values. Otherwise, you'll need to do some calculations and decision making before you can
fill those fields in. For a new user, just put some random garbage in the password field.
Don't worry about what the password is right now, because you're going to change it in a
minute. The only character you cannot include in the password field is a colon. Leave the
“days since password was changed” field blank as well. Fill in <var
class="LITERAL">0</var>, <var class="LITERAL">99999</var>, and <var
class="LITERAL">7</var> just as you see in the example entry, and leave the other fields
blank.</p>
<p>(For those of you who think you see my encrypted password above and believe you've got
a leg up on breaking into my system, go right ahead. If you can crack that password,
you'll know the password to a firewalled test system. Now that's useful :) )</p>
<p>All normal users are members of the “<tt class="USERNAME">users</tt>”
group on a typical Slackware system. However, if you want to create a new group, or add
the new user to additional groups, you'll need to modify the <tt
class="FILENAME">/etc/group</tt> file. Here is a typical entry:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="PROGRAMLISTING">
cvs::102:chris,logan,david,root
</pre>
</td>
</tr>
</table>
<p>The fields are group name, group password, group ID, and group members, separated by
commas. Creating a new group is a simple matter of adding a new line with a unique group
ID, and listing all the users you want to be in the group. Any users that are in this new
group and are logged in will have to log out and log back in for those changes to take
effect.</p>
<p>At this point, it might be a good idea to use the <tt class="COMMAND">pwck</tt> and
<tt class="COMMAND">grpck</tt> commands to verify that the changes you've made are
consistent. First, use <tt class="COMMAND">pwck -r</tt> and <tt class="COMMAND">grpck
-r</tt>: the <var class="OPTION">-r</var> switch makes no changes, but lists the changes
you would be asked to make if you ran the command without the switch. You can use this
output to decide whether you need to further modify any files, to run <tt
class="COMMAND">pwck</tt> or <tt class="COMMAND">grpck</tt> without the <var
class="OPTION">-r</var> switch, or to simply leave your changes as they are.</p>
<p>At this point, you should use the <tt class="COMMAND">passwd</tt> command to create a
proper password for the user. Then, use <tt class="COMMAND">mkdir</tt> to create the new
user's home directory in the location you entered into the <tt
class="FILENAME">/etc/passwd</tt> file, and use <tt class="COMMAND">chown</tt> to change
the owner of the new directory to the new user.</p>
<p>Removing a user is a simple matter of deleting all of the entries that exist for that
user. Remove the user's entry from <tt class="FILENAME">/etc/passwd</tt> and <tt
class="FILENAME">/etc/shadow</tt>, and remove the login name from any groups in the <tt
class="FILENAME">/etc/group</tt> file. If you wish, delete the user's home directory, the
mail spool file, and his crontab entry (if they exist).</p>
<p>Removing groups is similar: remove the group's entry from <tt
class="FILENAME">/etc/group</tt>.</p>
</div>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="ESSENTIAL-SYSADMIN-SHUTDOWN"
name="ESSENTIAL-SYSADMIN-SHUTDOWN">12.3 Shutting Down Properly</a></h2>
<p>It is very important that you shut down your system properly. Simply turning the power
off with the power switch can cause serious filesystem damage. While the system is on,
files are in use even if you aren't doing anything. Remember that there are many
processes running in the background all the time. These processes are managing the system
and keep a lot of files open. When the system's power is switched off, these files are
not closed properly and may become corrupted. Depending on what files become damaged, the
system might be rendered completely unusable! In any case, you'll have to go through a
long filesystem check procedure on the next reboot.</p>
<div class="NOTE">
<table class="NOTE" width="100%" border="0">
<tr>
<td width="25" align="CENTER" valign="TOP"><img src="./imagelib/admon/note.png"
hspace="5" alt="Note" /></td>
<td align="LEFT" valign="TOP">
<p>If you configured your system with a journalling filesystem, like ext3 or reiserfs,
you'll be partially protected from filesystem damage, and your filesystem check on reboot
will be shorter than if you had used a filesystem without journalling, like ext2.
However, this safety net is no excuse for improperly shutting down your system! A
journalling FS is meant to protect your files from events beyond your control, not from
your own laziness.</p>
</td>
</tr>
</table>
</div>
<p>In any case, when you want to reboot or power down your computer, it is important to
do so properly. There are several ways of doing so; you can pick whichever one you think
is the most fun (or least amount of work). Since a shutdown and a reboot are similar
procedures, most of the ways for powering off the system can also be applied to
rebooting.</p>
<p>The first method is through the <tt class="COMMAND">shutdown</tt>(8) program, and it
is probably the most popular. <tt class="COMMAND">shutdown</tt> can be used to reboot or
turn off the system at a given time, and can display a message to all the logged-in users
of the system telling them that the system is going down.</p>
<p>The most basic use of shutdown to power down the computer is:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">#</samp> <kbd class="USERINPUT">shutdown -h now</kbd>
</pre>
</td>
</tr>
</table>
<p>In this case, we are not going to send a custom message to the users; they will see
<tt class="COMMAND">shutdown</tt>'s default message. “<var
class="OPTION">now</var>” is the time that we want to shutdown, and the “<var
class="OPTION">-h</var>” means to halt the system. This is not a very friendly way
to run a multi-user system, but it works just fine on your home computer. A better method
on a multiuser system would be to give everyone a little advance warning:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">#</samp> <kbd class="USERINPUT">shutdown -h +60</kbd>
</pre>
</td>
</tr>
</table>
<p>This would shutdown the system in one hour (60 minutes), which would be just fine on a
normal multiuser system. Vital systems should have their downtime scheduled far in
advance, and you should post warnings about the downtime in any appropriate locations
used for system notifications (email, bulletin board, <tt
class="FILENAME">/etc/motd</tt>, whatever).</p>
<p>Rebooting the system uses the same command, but substitutes “<var
class="OPTION">-r</var>” for “<var class="OPTION">-h</var>”:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">#</samp> <kbd class="USERINPUT">shutdown -r now</kbd>
</pre>
</td>
</tr>
</table>
<p>You can use same time notation with <tt class="COMMAND">shutdown -r</tt> that you
could with <tt class="COMMAND">shutdown -h</tt>. There are a lot of other things that you
can do with <tt class="COMMAND">shutdown</tt> to control when to halt or reboot the
machine; see the man page for more details.</p>
<p>The second way of shutting down or powering off the computer is to use the <tt
class="COMMAND">halt</tt>(8) and <tt class="COMMAND">reboot</tt>(8) commands. As the
names indicate, <tt class="COMMAND">halt</tt> will immediately halt the operating system,
and <tt class="COMMAND">reboot</tt> will reboot the system. (<tt
class="COMMAND">reboot</tt> is actually just a symbolic link to <tt
class="COMMAND">halt</tt>.) They are invoked like so:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">#</samp> <kbd class="USERINPUT">halt</kbd>
<samp class="PROMPT">#</samp> <kbd class="USERINPUT">reboot</kbd>
</pre>
</td>
</tr>
</table>
<p>A lower-level way to reboot or shutdown the system is to talk directly to <tt
class="COMMAND">init</tt>. All the other methods are simply convenient ways to talk to
<tt class="COMMAND">init</tt>, but you can directly tell it what to do using <tt
class="COMMAND">telinit</tt>(8) (note that it only has one “l”). Using <tt
class="COMMAND">telinit</tt> will tell <tt class="COMMAND">init</tt> what runlevel to
drop into, which will cause a special script to be run. This script will kill or spawn
processes as needed for that runlevel. This works for rebooting and shutting down because
both of those are special runlevels.</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">#</samp> <kbd class="USERINPUT">telinit 0</kbd>
</pre>
</td>
</tr>
</table>
<p>Runlevel 0 is halt mode. Telling <tt class="COMMAND">init</tt> to enter runlevel 0
will cause all processes to be killed off, the filesystems unmounted, and the machine to
be halted. This is a perfectly acceptable way to bring down the system. On many laptops
and modern desktop computers, this will also cause the machine to be turned off.</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">#</samp> <kbd class="USERINPUT">telinit 6</kbd>
</pre>
</td>
</tr>
</table>
<p>Runlevel 6 is reboot mode. All processes will be killed off, the filesystems will be
unmounted, and the machine will be rebooted. This is a perfectly acceptable method of
rebooting the system.</p>
<p>For the curious, when switching to runlevel 0 or 6, whether by using <tt
class="COMMAND">shutdown</tt>, <tt class="COMMAND">halt</tt>, or <tt
class="COMMAND">reboot</tt>, the script <tt class="FILENAME">/etc/rc.d/rc.6</tt> is run.
(The script <tt class="FILENAME">/etc/rc.d/rc.0</tt> is another symbolic link, to <tt
class="FILENAME">/etc/rc.d/rc.6</tt>.) You can customize this file to your tastes--but be
sure to test your changes carefully!</p>
<p>There is one last method of rebooting the system. All the other methods require you to
be logged in as <tt class="USERNAME">root</tt>. However, it is possible to reboot the
machine even if you aren't root, provided that you have physical access to the keyboard.
Using <b class="KEYCAP">Control</b>+<b class="KEYCAP">Alt</b>+<b
class="KEYCAP">Delete</b> (the "three-fingered salute") will cause the machine to
immediately reboot. (Behind the scenes, the <tt class="COMMAND">shutdown</tt> command is
called for you when you use <b class="KEYCAP">Control</b>+<b class="KEYCAP">Alt</b>+<b
class="KEYCAP">Delete</b>.) The salute doesn't always work when using X Windows--you may
need to use <b class="KEYCAP">Control</b>+<b class="KEYCAP">Alt</b>+<b
class="KEYCAP">F1</b> (or another Function key) to switch to a non-X Windows terminal
before using it.</p>
<p>Finally, the file that ultimately controls every aspect of startup and shutdown is the
<tt class="FILENAME">/etc/inittab</tt>(5) file. In general, you should not need to modify
this file, but it may give you insight into why some things work the way they do. As
always, see the man pages for further details.</p>
</div>
</div>
<div class="CHAPTER">
<hr />
<h1><a id="BASIC-NETWORK-COMMANDS" name="BASIC-NETWORK-COMMANDS"></a>Chapter 13 Basic
Network Commands</h1>
<p>A network consists of several computers connected together. The network can be as
simple as a few computers connected in your home or office, or as complicated as a large
university network or even the entire Internet. When your computer is part of a network,
you have access to those systems either directly or through services like mail and the
web.</p>
<p>There are a variety of networking programs that you can use. Some are handy for
performing diagnostics to see if everything is working properly. Others (like mail
readers and web browsers) are useful for getting your work done and staying in contact
with other people.</p>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="BASIC-NETWORK-COMMANDS-PING"
name="BASIC-NETWORK-COMMANDS-PING">13.1 <tt class="COMMAND">ping</tt></a></h2>
<p><tt class="COMMAND">ping</tt>(8) sends an ICMP <var class="LITERAL">ECHO_REQUEST</var>
packet to the specified host. If the host responds, you get an ICMP packet back. Sound
strange? Well, you can “ping” an IP address to see if a machine is alive. If
there is no response, you know something is wrong. Here is an example conversation
between two Linux users:</p>
<a id="AEN4428" name="AEN4428"></a>
<blockquote class="BLOCKQUOTE">
<p class="LITERALLAYOUT"><span class="emphasis"><i class="EMPHASIS">User
A</i></span>: Loki's down again.<br />
<span class="emphasis"><i class="EMPHASIS">User
B</i></span>: Are you sure?<br />
<span class="emphasis"><i class="EMPHASIS">User
A</i></span>: Yeah, I tried pinging it, but there's no response.</p>
</blockquote>
<p>It's instances like these that make <tt class="COMMAND">ping</tt> a very useful
day-to-day command. It provides a very quick way to see if a machine is up and connected
to the network. The basic syntax is:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">ping www.slackware.com</kbd>
</pre>
</td>
</tr>
</table>
<p>There are, of course, several options that can be specified. Check the <tt
class="COMMAND">ping</tt>(1) man page for more information.</p>
</div>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="BASIC-NETWORK-COMMANDS-TRACEROUTE"
name="BASIC-NETWORK-COMMANDS-TRACEROUTE">13.2 <tt
class="COMMAND">traceroute</tt></a></h2>
<p>Slackware's <tt class="COMMAND">traceroute</tt>(8) command is a very useful network
diagnostic tool. <tt class="COMMAND">traceroute</tt> displays each host that a packet
travels through as it tries to reach its destination. You can see how many
“hops” from the Slackware web site you are with this command:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">traceroute www.slackware.com</kbd>
</pre>
</td>
</tr>
</table>
<p>Each host will be displayed, along with the response times at each host. Here is an
example output:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">traceroute www.slackware.com</kbd>
traceroute to www.slackware.com (204.216.27.13), 30 hops max, 40 byte packets
1 zuul.tdn (192.168.1.1) 0.409 ms 1.032 ms 0.303 ms
2 207.171.227.254 (207.171.227.254) 18.218 ms 32.873 ms 32.433 ms
3 border-sf-2-0-4.sirius.com (205.134.230.254) 15.662 ms 15.731 ms 16.142 ms
4 pb-nap.crl.net (198.32.128.20) 20.741 ms 23.672 ms 21.378 ms
5 E0-CRL-SFO-03-E0X0.US.CRL.NET (165.113.55.3) 22.293 ms 21.532 ms 21.29 ms
6 T1-CDROM-00-EX.US.CRL.NET (165.113.118.2) 24.544 ms 42.955 ms 58.443 ms
7 www.slackware.com (204.216.27.13) 38.115 ms 53.033 ms 48.328 ms
</pre>
</td>
</tr>
</table>
<p><tt class="COMMAND">traceroute</tt> is similar to <tt class="COMMAND">ping</tt> in
that it uses ICMP packets. There are several options that you can specify with <tt
class="COMMAND">traceroute</tt>. These options are explained in detail in the man
page.</p>
</div>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="BASIC-NETWORK-COMMANDS-DNS"
name="BASIC-NETWORK-COMMANDS-DNS">13.3 DNS Tools</a></h2>
<p>Domain Name Service (DNS for short) is that magical protocol that allows your computer
to turn meaningless domain names like www.slackware.com into meaningful IP address like
<tt class="HOSTID">64.57.102.34</tt>. Computers can't route packets to www.slackware.com,
but they can route packets to that domain name's IP address. This gives us a convenient
way to remember machines. Without DNS we'd have to keep a mental database of just what IP
address belongs to what computer, and that's assuming the IP address doesn't change.
Clearly using names for computers is better, but how do we map names to IP addresses?</p>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="AEN4475" name="AEN4475">13.3.1 <tt
class="COMMAND">host</tt></a></h3>
<p><tt class="COMMAND">host</tt>(1) can do this for us. <tt class="COMMAND">host</tt> is
used to map names to IP addresses. It is a very quick and simple utility without a lot of
functions.</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">host www.slackware.com</kbd>
www.slackware.com is an alias for slackware.com.
slackware.com has address 64.57.102.34
</pre>
</td>
</tr>
</table>
<p>But let's say for some reason we want to map an IP address to a domain name; what
then?</p>
</div>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="AEN4487" name="AEN4487">13.3.2 <tt
class="COMMAND">nslookup</tt></a></h3>
<p><tt class="COMMAND">nslookup</tt> is a tried and true program that has weathered the
ages. <tt class="COMMAND">nslookup</tt> has been deprecated and may be removed from
future releases. There is not even a man page for this program.</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">nslookup 64.57.102.34</kbd>
Note: nslookup is deprecated and may be removed from future releases.
Consider using the `dig' or `host' programs instead. Run nslookup with
the `-sil[ent]' option to prevent this message from appearing.
Server: 192.168.1.254
Address: 192.168.1.254#53
Non-authoritative answer:
www.slackware.com canonical name = slackware.com.
Name: slackware.com
Address: 64.57.102.34
</pre>
</td>
</tr>
</table>
</div>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="AEN4496" name="AEN4496">13.3.3 <tt
class="COMMAND">dig</tt></a></h3>
<p>The meanest dog in the pound, the domain information groper, <tt
class="COMMAND">dig</tt>(1) for short, is the go-to program for finding DNS information.
<tt class="COMMAND">dig</tt> can grab just about anything from a DNS server including
reverse lookups, A, CNAME, MX, SP, and TXT records. <tt class="COMMAND">dig</tt> has many
command line options and if you're not familiar with it you should read through it's
extensive man page.</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd
class="USERINPUT">dig @192.168.1.254 www.slackware.com mx</kbd>
; <<>> DiG 9.2.2 <<>> @192.168.1.254 www.slackware.com mx
;; global options: printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 26362
;; flags: qr rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 2, ADDITIONAL: 2
;; QUESTION SECTION:
;www.slackware.com. IN MX
;; ANSWER SECTION:
www.slackware.com. 76634 IN CNAME slackware.com.
slackware.com. 86400 IN MX 1 mail.slackware.com.
;; AUTHORITY SECTION:
slackware.com. 86400 IN NS ns1.cwo.com.
slackware.com. 86400 IN NS ns2.cwo.com.
;; ADDITIONAL SECTION:
ns1.cwo.com. 163033 IN A 64.57.100.2
ns2.cwo.com. 163033 IN A 64.57.100.3
;; Query time: 149 msec
;; SERVER: 192.168.1.254#53(192.168.1.254)
;; WHEN: Sat Nov 6 16:59:31 2004
;; MSG SIZE rcvd: 159
</pre>
</td>
</tr>
</table>
<p>This should give you an idea how <tt class="COMMAND">dig</tt> works.
“@192.168.1.254” specifies the dns server to use.
“www.slackware.com” is the domain name I am performing a lookup on, and
“mx” is the type of lookup I am performing. The above query tells me that
e-mail to <tt class="HOSTID">www.slackware.com</tt> will instead be sent to <tt
class="HOSTID">mail.slackware.com</tt> for delivery.</p>
</div>
</div>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="BASIC-NETWORK-COMMANDS-FINGER"
name="BASIC-NETWORK-COMMANDS-FINGER">13.4 <tt class="COMMAND">finger</tt></a></h2>
<p><tt class="COMMAND">finger</tt>(1) will retrieve information about the specified user.
You give finger a username or an email address and it will try to contact the necessary
server and retrieve the username, office, telephone number, and other pieces of
information. Here is an example:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">finger johnc@idsoftware.com</kbd>
</pre>
</td>
</tr>
</table>
<p><tt class="COMMAND">finger</tt> can return the username, mail status, phone numbers,
and files referred to as “dot plan” and “dot project”. Of course,
the information returned varies with each <tt class="COMMAND">finger</tt> server. The one
included with Slackware returns the following information by default:</p>
<ul>
<li>
<p>Username</p>
</li>
<li>
<p>Room number</p>
</li>
<li>
<p>Home phone number</p>
</li>
<li>
<p>Work phone number</p>
</li>
<li>
<p>Login status</p>
</li>
<li>
<p>Email status</p>
</li>
<li>
<p>Contents of the <tt class="FILENAME">.plan</tt> file in the user's home directory</p>
</li>
<li>
<p>Contents of the <tt class="FILENAME">.project</tt> file in the user's home
directory</p>
</li>
</ul>
<p>The first four items can be set with the <tt class="COMMAND">chfn</tt> command. It
stores those values in the <tt class="FILENAME">/etc/passwd</tt> file. To change the
information in your <tt class="FILENAME">.plan</tt> or <tt class="FILENAME">.project</tt>
file, just edit them with your favorite text editor. They must reside in your home
directory and must be called <tt class="FILENAME">.plan</tt> and <tt
class="FILENAME">.project</tt>.</p>
<p>Many users <tt class="COMMAND">finger</tt> their own account from a remote machine to
quickly see if they have new email. Or, you can see a user's plan or current project.</p>
<p>Like many commands, <tt class="COMMAND">finger</tt> has options. Check the man page
for more information on what special options you can use.</p>
</div>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="BASIC-NETWORK-COMMANDS-TELNET"
name="BASIC-NETWORK-COMMANDS-TELNET">13.5 <tt class="COMMAND">telnet</tt></a></h2>
<p>Someone once stated that <tt class="COMMAND">telnet</tt>(1) was the coolest thing he
had ever seen on computers. The ability to remotely log in and do stuff on another
computer is what separates Unix and Unix-like operating systems from other operating
systems.</p>
<p><tt class="COMMAND">telnet</tt> allows you to log in to a computer, just as if you
were sitting at the terminal. Once your username and password are verified, you are given
a shell prompt. From here, you can do anything requiring a text console. Compose email,
read newsgroups, move files around, and so on. If you are running X and you <tt
class="COMMAND">telnet</tt> to another machine, you can run X programs on the remote
computer and display them on yours.</p>
<p>To login to a remote machine, use this syntax:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">telnet <<var
class="REPLACEABLE">hostname</var>></kbd>
</pre>
</td>
</tr>
</table>
<p>If the host responds, you will receive a login prompt. Give it your username and
password. That's it. You are now at a shell. To quit your telnet session, use either the
<tt class="COMMAND">exit</tt> command or the <tt class="COMMAND">logout</tt> command.</p>
<div class="WARNING">
<table class="WARNING" width="100%" border="0">
<tr>
<td width="25" align="CENTER" valign="TOP"><img src="./imagelib/admon/warning.png"
hspace="5" alt="Warning" /></td>
<td align="LEFT" valign="TOP">
<p><tt class="COMMAND">telnet</tt> does not encrypt the information it sends. Everything
is sent in plain text, even passwords. It is not advisable to use <tt
class="COMMAND">telnet</tt> over the Internet. Instead, consider the <tt
class="COMMAND">Secure Shell</tt>. It encrypts all traffic and is available for free.</p>
</td>
</tr>
</table>
</div>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="AEN4593" name="AEN4593">13.5.1 The other use of telnet</a></h3>
<p>Now that we have convinced you not to use the telnet protocol anymore to log into a
remote machine, we'll show you a couple of useful ways to use <tt
class="COMMAND">telnet</tt>.</p>
<p>You can also use the <tt class="COMMAND">telnet</tt> command to connect to a host on a
certain port.</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">telnet <<var
class="REPLACEABLE">hostname</var>> [port]</kbd>
</pre>
</td>
</tr>
</table>
<p>This can be quite handy when you quickly need to test a certain service, and you need
full control over the commands, and you need to see what exactly is going on. You can
interactively test or use an SMTP server, a POP3 server, an HTTP server, etc. this
way.</p>
<p>In the next figure you'll see how you can <tt class="COMMAND">telnet</tt> to a HTTP
server on port 80, and get some basic information from it.</p>
<div class="FIGURE"><a id="FIG-BASIC-NETWORK-COMMANDS-TELNET-WEB"
name="FIG-BASIC-NETWORK-COMMANDS-TELNET-WEB"></a>
<p><b>Figure 13-1. Telnetting to a webserver</b></p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">telnet store.slackware.com 80</kbd>
Trying 69.50.233.153...
Connected to store.slackware.com.
Escape character is '^]'.
HEAD / HTTP/1.0
HTTP/1.1 200 OK
Date: Mon, 25 Apr 2005 20:47:01 GMT
Server: Apache/1.3.33 (Unix) mod_ssl/2.8.22 OpenSSL/0.9.7d
Last-Modified: Fri, 18 Apr 2003 10:58:54 GMT
ETag: "193424-c0-3e9fda6e"
Accept-Ranges: bytes
Content-Length: 192
Connection: close
Content-Type: text/html
Connection closed by foreign host.
<samp class="PROMPT">%</samp>
</pre>
</td>
</tr>
</table>
</div>
<p>You can do the same for other plain-text protocols, as long as you know what port to
connect to, and what the commands are.</p>
</div>
</div>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="BASIC-NETWORK-COMMANDS-SSH"
name="BASIC-NETWORK-COMMANDS-SSH">13.6 The Secure shell</a></h2>
<p>Today, secure shell basks in the adoration that <tt class="COMMAND">telnet</tt> once
enjoyed. <tt class="COMMAND">ssh</tt>(1) allows one to make a connection to a remote
machine and execute programs as if one were physically present; however, <tt
class="COMMAND">ssh</tt> encrypts all the data travelling between the two computers so
even if others intercept the conversation, they are unable to understand it. A typical
secure shell connection follows.</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd
class="USERINPUT">ssh carrier.lizella.net -l alan</kbd>
The authenticity of host 'carrier.lizella.net (192.168.1.253)' can't be
established.
RSA key fingerprint is 0b:e2:5d:43:4c:39:4f:8c:b9:85:db:b2:fa:25:e9:9d.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added 'carrier.lizella.net' (RSA) to the list of
known hosts.
Password: <kbd class="USERINPUT">password</kbd>
Last login: Sat Nov 6 16:32:19 2004 from 192.168.1.102
Linux 2.4.26-smp.
alan@carrier:~$ <kbd class="USERINPUT">ls -l MANIFEST</kbd>
-rw-r--r-- 1 alan users 23545276 2004-10-28 20:04 MANIFEST
alan@carrier:~$ <kbd class="USERINPUT">exit</kbd>
logout
Connection to carrier.lizella.net closed.
</pre>
</td>
</tr>
</table>
<p>There you see me making an ssh connection to <tt
class="HOSTID">carrier.lizella.net</tt>, and checking the permissions on the <tt
class="FILENAME">MANIFEST</tt> file.</p>
</div>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="BASIC-NETWORK-COMMANDS-EMAIL"
name="BASIC-NETWORK-COMMANDS-EMAIL">13.7 email</a></h2>
<p>Electronic mail is one of the most popular things one can do on the Internet. In 1998,
it was reported that more electronic mail was sent than regular mail. It is indeed common
and useful.</p>
<p>Under Slackware, we provide a standard mail server, and several mail clients. All of
the clients discussed below are text-based. A lot of Windows users may be against this,
but you will find that a text based client is very convenient, especially when checking
mail remotely. Fear not, there are many graphical e-mail clients such as KDE's Kmail. If
you wish to use one of those check its help menu.</p>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="BASIC-NETWORK-COMMANDS-EMAIL-PINE"
name="BASIC-NETWORK-COMMANDS-EMAIL-PINE">13.7.1 <tt class="COMMAND">pine</tt></a></h3>
<p><tt class="COMMAND">pine</tt>(1) is not <tt class="COMMAND">elm</tt>. Or so the saying
goes. The University of Washington created their program for Internet news and email out
of a need for an easy mail reader for their students. <tt class="COMMAND">pine</tt> is
one of the most popular email clients in use today and is available for nearly every
flavor of Unix and even Windows.</p>
<div class="FIGURE"><a id="FIG-BASIC-NETWORK-COMMANDS-EMAIL-PINE"
name="FIG-BASIC-NETWORK-COMMANDS-EMAIL-PINE"></a>
<p><b>Figure 13-2. The Pine main menu</b></p>
<p><img src="basic-network-commands/pine.png" /></p>
</div>
<p>You will see a menu of commands and a row of command keys at the bottom. <tt
class="COMMAND">pine</tt> is indeed a complex program, so we will not discuss every
feature about it here.</p>
<p>To see what's in your inbox, type <kbd class="USERINPUT">i</kbd>. Your messages are
listed with their date, author, and subject. Highlight the message you want and press
<kbd class="USERINPUT">enter</kbd> to view it. Pressing <kbd class="USERINPUT">r</kbd>
will start a reply to the message. Once you have written the response, type <b
class="KEYCAP">Ctrl</b>+<b class="KEYCAP">X</b> to send it. You can press <kbd
class="USERINPUT">i</kbd> to get back to the message listing.</p>
<p>If you want to delete a message, press <kbd class="USERINPUT">d</kbd>. It will mark
the highlighted message for deletion. <tt class="COMMAND">pine</tt> deletes the mail when
you exit the program. <tt class="COMMAND">pine</tt> also lets you store your mail in
folders. You can get a listing of folders by pressing <kbd class="USERINPUT">l</kbd>. At
the message listing, press <kbd class="USERINPUT">s</kbd> to save it to another folder.
It will ask for the folder name to write the message to.</p>
<p><tt class="COMMAND">pine</tt> offers many, many features; you should definitely have a
look at the man page for more information. It will contain the latest information about
the program.</p>
</div>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="BASIC-NETWORK-COMMANDS-EMAIL-ELM"
name="BASIC-NETWORK-COMMANDS-EMAIL-ELM">13.7.2 <tt class="COMMAND">elm</tt></a></h3>
<p><tt class="COMMAND">elm</tt>(1) is another popular text-based email client. Though not
quite as user friendly as <tt class="COMMAND">pine</tt>, it's definitely been around a
lot longer.</p>
<div class="FIGURE"><a id="FIG-BASIC-NETWORK-COMMANDS-EMAIL-ELM"
name="FIG-BASIC-NETWORK-COMMANDS-EMAIL-ELM"></a>
<p><b>Figure 13-3. Elm main screen</b></p>
<p><img src="basic-network-commands/elm.png" /></p>
</div>
<p>By default, you are placed in your inbox. The messages are listed with the message
number, date, sender, and subject. Use the arrow keys to highlight the message you want.
Press <kbd class="USERINPUT">Enter</kbd> to read the message.</p>
<p>To compose a new message, type <kbd class="USERINPUT">m</kbd> at the main screen. The
<kbd class="USERINPUT">d</kbd> key will flag a message for deletion. And the <kbd
class="USERINPUT">r</kbd> key will reply to the current message you are reading. All of
these keys are displayed at the bottom of the screen with a prompt.</p>
<p>The man page discusses <tt class="COMMAND">elm</tt> in more detail, so you will
probably want to consult that before using <tt class="COMMAND">elm</tt>.</p>
</div>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="BASIC-NETWORK-COMMANDS-EMAIL-MUTT"
name="BASIC-NETWORK-COMMANDS-EMAIL-MUTT">13.7.3 <tt class="COMMAND">mutt</tt></a></h3>
<p>“All mail clients suck. This one just sucks less.” <tt
class="COMMAND">mutt</tt>'s original interface was based on <tt class="COMMAND">elm</tt>
with added features found in other popular mailclients, resulting in a hybrid mutt.</p>
<p>Some of <tt class="COMMAND">mutt</tt>'s features include:</p>
<ul>
<li>
<p>color support</p>
</li>
<li>
<p>message threading</p>
</li>
<li>
<p>MIME and PGP/MIME support</p>
</li>
<li>
<p>pop3 and imap support</p>
</li>
<li>
<p>support for multiple mailbox formats (mbox, MMDF, MH, maildir)</p>
</li>
<li>
<p><span class="emphasis"><i class="EMPHASIS">highly</i></span> customizable</p>
</li>
</ul>
<div class="FIGURE"><a id="FIG-BASIC-NETWORK-COMMANDS-EMAIL-MUTT"
name="FIG-BASIC-NETWORK-COMMANDS-EMAIL-MUTT"></a>
<p><b>Figure 13-4. Mutt main screen</b></p>
<p><img src="basic-network-commands/mutt.png" /></p>
</div>
<p>if you're looking for a mail client that will let you be in total control over
everything, then you will like <tt class="COMMAND">mutt</tt>. all the default settings
can be customized, keybindings can be changed. if you like to add a macro, you can.</p>
<p>you probably want to take a look at the <tt class="FILENAME">muttrc</tt> manpage,
which will tell you how to configure everything. or take a look at the included example
<tt class="FILENAME">muttrc</tt> file.</p>
</div>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="BASIC-NETWORK-COMMANDS-EMAIL-NAIL"
name="BASIC-NETWORK-COMMANDS-EMAIL-NAIL">13.7.4 <tt class="COMMAND">nail</tt></a></h3>
<p><tt class="COMMAND">nail</tt>(1) is a command line driven mail client. It is very
primitive and offers pretty much nothing in the way of user interfaces. However, mailx is
handy for times when you need to quickly mail something, scripting a bulk mailer, testing
your MTA installation or something similar. Note that Slackware creates symbolic links to
<tt class="COMMAND">nail</tt> at <tt class="FILENAME">/usr/bin/mail</tt> and <tt
class="FILENAME">/usr/bin/mailx</tt>. Any of these three commands executes the same
program. In fact, you will most likely see <tt class="COMMAND">nail</tt> referred to as
<tt class="COMMAND">mail</tt>.</p>
<p>The basic command line is:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd
class="USERINPUT">mailx <subject> <to-addr></kbd>
</pre>
</td>
</tr>
</table>
<p><tt class="COMMAND">mailx</tt> reads the message body from standard input. So you can
cat a file into this command to mail it, or you can just type text and hit <b
class="KEYCAP">Ctrl</b>+<b class="KEYCAP">D</b> when finished with the message.</p>
<p>Here is an example of mailing a program source file to another person.</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd
class="USERINPUT">cat randomfunc.c | mail -s "Here's that function" asdf@example.net</kbd>
</pre>
</td>
</tr>
</table>
<p>The man page explains more of what <tt class="COMMAND">nail</tt> can do, so you will
probably want to have a look at that before using it.</p>
</div>
</div>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="BASIC-NETWORK-COMMANDS-WEB"
name="BASIC-NETWORK-COMMANDS-WEB">13.8 Browsers</a></h2>
<p>The first thing that people think about when they hear the word Internet is
“surfing the net”. Or looking at websites using a web browser. This is
probably by far the most popular use of the Internet for the average user.</p>
<p>Slackware provides popular graphical web browsers in the “XAP” series, as
well as text mode browsers in the “N” series. We'll take a quick look at some
of the most common options below.</p>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="AEN4776" name="AEN4776">13.8.1 <tt
class="COMMAND">lynx</tt></a></h3>
<p><tt class="COMMAND">lynx</tt>(1) is a text-based web browser. It is a very quick way
of looking up something on the Internet. Sometimes graphics just get in the way if you
know exactly what you're after.</p>
<p>To start <tt class="COMMAND">lynx</tt>, just type <tt class="COMMAND">lynx</tt> at the
prompt:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">lynx</kbd>
</pre>
</td>
</tr>
</table>
<div class="FIGURE"><a id="FIG-BASIC-NETWORK-COMMANDS-WEB-LYNX"
name="FIG-BASIC-NETWORK-COMMANDS-WEB-LYNX"></a>
<p><b>Figure 13-5. Lynx default start page</b></p>
<p><img src="basic-network-commands/lynx.png" /></p>
</div>
<p>You may want to specify a site for <tt class="COMMAND">lynx</tt> to open to:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">lynx http://www.slackware.com</kbd>
</pre>
</td>
</tr>
</table>
<p><tt class="COMMAND">lynx</tt> prints the command keys and what they do at the bottom
of the screen. The up and down arrow keys move around the document, <kbd
class="USERINPUT">Enter</kbd> selects the highlighted link, and the <kbd
class="USERINPUT">left arrow</kbd> goes back to the previous page. Typing <kbd
class="USERINPUT">d</kbd> will download the currently selected file. The <kbd
class="USERINPUT">g</kbd> command brings up the Go prompt, where you can give <tt
class="COMMAND">lynx</tt> a URL to open.</p>
<p>There are many other commands in <tt class="COMMAND">lynx</tt>. You can either consult
the man page, or type <kbd class="USERINPUT">h</kbd> to get the help screen for more
information.</p>
</div>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="AEN4813" name="AEN4813">13.8.2 <tt
class="COMMAND">links</tt></a></h3>
<p>Just like <tt class="COMMAND">lynx</tt>, <tt class="COMMAND">links</tt> is a textmode
web browser, where you do all the navigation using the keyboard. However, when you press
the <kbd class="USERINPUT">Esc</kbd> key, it will activate a very convenient pulldown
menu on the top of the screen. This makes it very easy to use, without having to learn
all the keyboard shortcuts. People who do not use a text browser every day will
appreciate this feature.</p>
<p><tt class="COMMAND">links</tt> seems to have better support for both frames and
tables, when compared to <tt class="COMMAND">lynx</tt>.</p>
<div class="FIGURE"><a id="FIG-BASIC-NETWORK-COMMANDS-WEB-LINKS"
name="FIG-BASIC-NETWORK-COMMANDS-WEB-LINKS"></a>
<p><b>Figure 13-6. Links, with the file menu open</b></p>
<p><img src="basic-network-commands/links.png" /></p>
</div>
</div>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="AEN4831" name="AEN4831">13.8.3 <tt
class="COMMAND">wget</tt></a></h3>
<p><tt class="COMMAND">wget</tt>(1) is a command line utility that will download files
from a specified URL. While not an actual web-browser, <tt class="COMMAND">wget</tt> is
used primarily to grab whole or partial web sites for offline viewing, or for fast
download of single files from HTTP or FTP servers instead. The basic syntax is:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">wget <url></kbd>
</pre>
</td>
</tr>
</table>
<p>You can also pass options. For example, this will download the Slackware web site:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd
class="USERINPUT">wget --recursive http://www.slackware.com</kbd>
</pre>
</td>
</tr>
</table>
<p><tt class="COMMAND">wget</tt> will create a <tt
class="FILENAME">www.slackware.com</tt> directory and store the files in there, just as
the site does.</p>
<p><tt class="COMMAND">wget</tt> can also download files from FTP sites; just specify an
FTP URL instead of an HTTP one.</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd
class="USERINPUT">wget ftp://ftp.gnu.org/gnu/wget/wget-1.8.2.tar.gz</kbd>
--12:18:16-- ftp://ftp.gnu.org/gnu/wget/wget-1.8.2.tar.gz
=> `wget-1.8.2.tar.gz'
Resolving ftp.gnu.org... done.
Connecting to ftp.gnu.org[199.232.41.7]:21... connected.
Logging in as anonymous ... Logged in!
==> SYST ... done. ==> PWD ... done.
==> TYPE I ... done. ==> CWD /gnu/wget ... done.
==> PORT ... done. ==> RETR wget-1.8.2.tar.gz ... done.
Length: 1,154,648 (unauthoritative)
100%[==================================>] 1,154,648 209.55K/s ETA 00:00
12:18:23 (209.55KB/s) - `wget-1.8.2.tar.gz' saved [1154648]
</pre>
</td>
</tr>
</table>
<p><tt class="COMMAND">wget</tt> has many more options, which make it nice for site
specific scripts (web site mirroring and so forth). The man page should be consulted for
more information.</p>
</div>
</div>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="BASIC-NETWORK-COMMANDS-FTP"
name="BASIC-NETWORK-COMMANDS-FTP">13.9 FTP Clients</a></h2>
<p>FTP stands for the File Transfer Protocol. It allows you to send and receive files
between two computers. There is the FTP server and the FTP client. We discuss the client
in this section.</p>
<p>For the curious, the “client” is you. The “server” is the
computer that answers your FTP request and lets you login. You will download files from
and upload files to the server. The client cannot accept FTP connections, it can only
connect to servers.</p>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="AEN4871" name="AEN4871">13.9.1 <tt
class="COMMAND">ftp</tt></a></h3>
<p>To connect to an FTP server, simply run the <tt class="COMMAND">ftp</tt>(1) command
and specify the host:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">ftp <hostname> [port]</kbd>
</pre>
</td>
</tr>
</table>
<p>If the host is running an FTP server, it will ask for a username and password. You can
log in as yourself or as “anonymous”. Anonymous FTP sites are very popular
for software archives. For example, to get Slackware Linux via FTP, you must use
anonymous FTP.</p>
<p>Once connected, you will be at the <var class="LITERAL">ftp></var> prompt. There
are special commands for FTP, but they are similar to other standard commands. The
following shows some of the basic commands and what they do:</p>
<div class="TABLE"><a id="AEN4883" name="AEN4883"></a>
<p><b>Table 13-1. <tt class="COMMAND">ftp</tt> commands</b></p>
<table border="0" frame="void" class="CALSTABLE">
<col width="1*" />
<col width="3*" />
<thead>
<tr>
<th>Command</th>
<th>Purpose</th>
</tr>
</thead>
<tbody>
<tr>
<td><tt class="COMMAND">ls</tt></td>
<td>List files</td>
</tr>
<tr>
<td><tt class="COMMAND">cd <dirname></tt></td>
<td>Change directory</td>
</tr>
<tr>
<td><tt class="COMMAND">bin</tt></td>
<td>Set binary transfer mode</td>
</tr>
<tr>
<td><tt class="COMMAND">ascii</tt></td>
<td>Set ASCII transfer mode</td>
</tr>
<tr>
<td><tt class="COMMAND">get <filename></tt></td>
<td>Download a file</td>
</tr>
<tr>
<td><tt class="COMMAND">put <filename></tt></td>
<td>Upload a file</td>
</tr>
<tr>
<td><tt class="COMMAND">hash</tt></td>
<td>Toggle hash mark stats indicator</td>
</tr>
<tr>
<td><tt class="COMMAND">tick</tt></td>
<td>Toggle byte counter indicator</td>
</tr>
<tr>
<td><tt class="COMMAND">prom</tt></td>
<td>Toggle interactive mode for downloads</td>
</tr>
<tr>
<td><tt class="COMMAND">mget <mask></tt></td>
<td>Download a file or group of files; wildcards are allowed</td>
</tr>
<tr>
<td><tt class="COMMAND">mput <mask></tt></td>
<td>Upload a file or group of files; wildcards are allowed</td>
</tr>
<tr>
<td><tt class="COMMAND">quit</tt></td>
<td>Log off the FTP server</td>
</tr>
</tbody>
</table>
</div>
<p>You can also use some of the following commands which are quite self-explanatory: <tt
class="COMMAND">chmod</tt>, <tt class="COMMAND">delete</tt>, <tt
class="COMMAND">rename</tt>, <tt class="COMMAND">rmdir</tt>. For a complete list of all
commands and their meaning, just type <kbd class="USERINPUT">help</kbd> or <kbd
class="USERINPUT">?</kbd> and you'll see a complete listing on screen.</p>
<p>FTP is a fairly simple program to use, but lacks the user interface that many of us
are used to nowadays. The man page discusses some of the command line options for <tt
class="COMMAND">ftp</tt>(1).</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
ftp> <kbd class="USERINPUT">ls *.TXT</kbd>
200 PORT command successful.
150 Opening ASCII mode data connection for /bin/ls.
-rw-r--r-- 1 root 100 18606 Apr 6 2002 BOOTING.TXT
-rw-r--r-- 1 root 100 10518 Jun 13 2002 COPYRIGHT.TXT
-rw-r--r-- 1 root 100 602 Apr 6 2002 CRYPTO_NOTICE.TXT
-rw-r--r-- 1 root 100 32431 Sep 29 02:56 FAQ.TXT
-rw-r--r-- 1 root 100 499784 Mar 3 19:29 FILELIST.TXT
-rw-r--r-- 1 root 100 241099 Mar 3 19:12 PACKAGES.TXT
-rw-r--r-- 1 root 100 12339 Jun 19 2002 README81.TXT
-rw-r--r-- 1 root 100 14826 Jun 17 2002 SPEAKUP_DOCS.TXT
-rw-r--r-- 1 root 100 15434 Jun 17 2002 SPEAK_INSTALL.TXT
-rw-r--r-- 1 root 100 2876 Jun 17 2002 UPGRADE.TXT
226 Transfer complete.
ftp> <kbd class="USERINPUT">tick</kbd>
Tick counter printing on (10240 bytes/tick increment).
ftp> <kbd class="USERINPUT">get README81.TXT</kbd>
local: README81.TXT remote: README81.TXT
200 PORT command successful.
150 Opening BINARY mode data connection for README81.TXT (12339 bytes).
Bytes transferred: 12339
226 Transfer complete.
12339 bytes received in 0.208 secs (58 Kbytes/sec)
</pre>
</td>
</tr>
</table>
</div>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="BASIC-NETWORK-COMMANDS-FTP-NCFTP"
name="BASIC-NETWORK-COMMANDS-FTP-NCFTP">13.9.2 <tt class="COMMAND">ncftp</tt></a></h3>
<p><tt class="COMMAND">ncftp</tt>(1) (pronounced "Nik-F-T-P") is an alternative to the
traditional ftp client that comes with Slackware. It is still a text-based program, but
offers many advantages over <tt class="COMMAND">ftp</tt>, including:</p>
<ul>
<li>
<p>Tab completion</p>
</li>
<li>
<p>Bookmarks file</p>
</li>
<li>
<p>More liberal wildcard uses</p>
</li>
<li>
<p>Command history</p>
</li>
</ul>
<p>By default, <tt class="COMMAND">ncftp</tt> will try to log in anonymously to the
server you specify. You can force <tt class="COMMAND">ncftp</tt> to present a login
prompt with the “<var class="OPTION">-u</var>” option. Once logged in, you
can use the same commands as in <tt class="COMMAND">ftp</tt>, only you'll notice a nicer
interface, one that works more like <tt class="COMMAND">bash</tt>.</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
ncftp /pub/linux/slackware > <kbd class="USERINPUT">cd slackware-current/</kbd>
Please read the file README81.TXT
it was last modified on Wed Jun 19 16:24:21 2002 - 258 days ago
CWD command successful.
ncftp ...ware/slackware-current > <kbd class="USERINPUT">ls</kbd>
BOOTING.TXT FAQ.TXT bootdisks/
CHECKSUMS FILELIST.TXT extra/
CHECKSUMS.asc GPG-KEY isolinux/
CHECKSUMS.md5 PACKAGES.TXT kernels/
CHECKSUMS.md5.asc PRERELEASE_NOTES pasture/
COPYING README81.TXT rootdisks/
COPYRIGHT.TXT SPEEKUP_DOCS.TXT slackware/
CRYPTO_NOTICE.TXT SPEEK_INSTALL.TXT source/
CURRENT.WARNING Slackware-HOWTO
ChangeLog.txt UPGRADE.TXT
ncftp ...ware/slackware-current > <kbd class="USERINPUT">get README81.TXT</kbd>
README81.TXT: 12.29 kB 307.07 kB/s
</pre>
</td>
</tr>
</table>
</div>
</div>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="BASIC-NETWORK-COMMANDS-TALK"
name="BASIC-NETWORK-COMMANDS-TALK">13.10 Talking to Other People</a></h2>
<div class="SECT2">
<h3 class="SECT2"><a id="AEN4989" name="AEN4989">13.10.1 <tt
class="COMMAND">wall</tt></a></h3>
<p><tt class="COMMAND">wall</tt>(1) is a quick way to write a message to the users on a
system. The basic syntax is:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">wall [file]</kbd>
</pre>
</td>
</tr>
</table>
<p>This will result in the contents of [file] being displayed on the terminals of all
currently logged in users. If you don't specify a file, wall will read from standard
input, so you can just type your message, and end with <b class="KEYCAP">Ctrl</b>+<b
class="KEYCAP">d</b>.</p>
<p><tt class="COMMAND">wall</tt> doesn't have many features, and apart from letting your
users know that you're about to do some serious maintenance to the system, or even reboot
it, so they have time to save their work and log off :)</p>
</div>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="AEN5006" name="AEN5006">13.10.2 <tt
class="COMMAND">talk</tt></a></h3>
<p><tt class="COMMAND">talk</tt>(1) allows two users to chat. It splits the screen in
half, horizontally. To request a chat with another user, use this command:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">talk <person> [ttyname]</kbd>
</pre>
</td>
</tr>
</table>
<div class="FIGURE"><a id="FIG-BASIC-NETWORK-COMMANDS-TALK-TALK"
name="FIG-BASIC-NETWORK-COMMANDS-TALK-TALK"></a>
<p><b>Figure 13-7. Two users in a <tt class="COMMAND">talk</tt> session</b></p>
<p><img src="basic-network-commands/talk.png" /></p>
</div>
<p>If you specify just a username, the chat request is assumed to be local, so only local
users are queried. The ttyname is required if you want to ring a user on a specific
terminal (if the user is logged in more than once). The required information for <tt
class="COMMAND">talk</tt> can be obtained from the <tt class="COMMAND">w</tt>(1)
command.</p>
<p><tt class="COMMAND">talk</tt> can also ring users on remote hosts. For the username
you simply specify an email address. <tt class="COMMAND">talk</tt> will try to contact
that remote user on that host.</p>
<p><tt class="COMMAND">talk</tt> is somewhat limited. It only supports two users and is
half-duplex.</p>
</div>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="AEN5033" name="AEN5033">13.10.3 <tt
class="COMMAND">ytalk</tt></a></h3>
<p><tt class="COMMAND">ytalk</tt>(1) is a backwards compatible replacement for <tt
class="COMMAND">talk</tt>. It comes with Slackware as the <tt class="COMMAND">ytalk</tt>
command. The syntax is similar, but has a few differences:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd
class="USERINPUT">ytalk <username>[#ttyname]</kbd>
</pre>
</td>
</tr>
</table>
<div class="FIGURE"><a id="FIG-BASIC-NETWORK-COMMANDS-TALK-YTALK"
name="FIG-BASIC-NETWORK-COMMANDS-TALK-YTALK"></a>
<p><b>Figure 13-8. Two users in a <tt class="COMMAND">ytalk</tt> session</b></p>
<p><img src="basic-network-commands/ytalk.png" /></p>
</div>
<p>The username and terminal are specified the same as under talk, except you must put
them together with the hash mark (#).</p>
<p>ytalk offers several advantages:</p>
<ul>
<li>
<p>It supports more than two users.</p>
</li>
<li>
<p>A menu of options that can be brought up anytime with <kbd
class="USERINPUT">Esc</kbd>.</p>
</li>
<li>
<p>You can shell out while still in the talk session.</p>
</li>
<li>
<p>Plus more...</p>
</li>
</ul>
<p>If you're a server administrator, you'll want to make sure that the <tt
class="COMMAND">ntalk</tt> port is enabled in <tt class="FILENAME">/etc/inetd.conf</tt>.
<tt class="COMMAND">ytalk</tt> needs that to work properly.</p>
</div>
</div>
</div>
<div class="CHAPTER">
<hr />
<h1><a id="SECURITY" name="SECURITY"></a>Chapter 14 Security</h1>
<p>Security on any system is important; it can prevent people launching attacks from your
machine, as well as protect sensitive data. This chapter is all about how to start
securing your Slackware box against script kiddies, crackers and rogue hamsters alike.
Bear in mind that this is only the start of securing a system; security is a process, not
a state.</p>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="SECURITY-DISABLE" name="SECURITY-DISABLE">14.1 Disabling
Services</a></h2>
<p>The first step after installing Slackware should be to disable any services you don't
need. Any services could potentially pose a security risk, so it is important to run as
few services as possible (i.e. only those that are needed). Services are started from two
main places - <tt class="COMMAND">inetd</tt> and init scripts.</p>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="AEN5081" name="AEN5081">14.1.1 Services started from <tt
class="COMMAND">inetd</tt></a></h3>
<p>A lot of the daemons that come with Slackware are run from <tt
class="COMMAND">inetd</tt>(8). <tt class="COMMAND">inetd</tt> is a daemon that listens on
all of the ports used by services configured to be started by it and spawns an instance
of the relevant daemon when a connection attempt is made. Daemons started from <tt
class="COMMAND">inetd</tt> can be disabled by commenting out the relevant lines in <tt
class="FILENAME">/etc/inetd.conf</tt>. To do this, open this file in your favorite editor
(e.g. <tt class="COMMAND">vi</tt>) and you should see lines similar to this:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="PROGRAMLISTING">
telnet stream tcp nowait root /usr/sbin/tcpd in.telnetd
</pre>
</td>
</tr>
</table>
<p>You can disable this service, and any others you don't need, by commenting them out
(i.e. adding a <var class="LITERAL">#</var> (hash) symbol to the beginning of the line).
The above line would then become:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="PROGRAMLISTING">
#telnet stream tcp nowait root /usr/sbin/tcpd in.telnetd
</pre>
</td>
</tr>
</table>
<p>After <tt class="COMMAND">inetd</tt> has been restarted, this service will be
disabled. You can restart <tt class="COMMAND">inetd</tt> with the command:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">#</samp> <kbd
class="USERINPUT">kill -HUP $(cat /var/run/inetd.pid)</kbd>
</pre>
</td>
</tr>
</table>
</div>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="AEN5102" name="AEN5102">14.1.2 Services started from init
scripts</a></h3>
<p>The rest of the services started when the machine starts are started from the init
scripts in <tt class="FILENAME">/etc/rc.d/</tt>. These can be disabled in two different
ways, the first being to remove the execute permissions on the relevant init script and
the second being to comment out the relevant lines in the init scripts.</p>
<p>For example, SSH is started by its own init script at <tt
class="FILENAME">/etc/rc.d/rc.sshd</tt>. You can disable this using:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">#</samp> <kbd class="USERINPUT">chmod -x /etc/rc.d/rc.sshd</kbd>
</pre>
</td>
</tr>
</table>
<p>For services that don't have their own init script, you will need to comment out the
relevant lines in the init scripts to disable them. For example, the portmap daemon is
started by the following lines in <tt class="FILENAME">/etc/rc.d/rc.inet2</tt>:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="PROGRAMLISTING">
# This must be running in order to mount NFS volumes.
# Start the RPC portmapper:
if [ -x /sbin/rpc.portmap ]; then
echo "Starting RPC portmapper: /sbin/rpc.portmap"
/sbin/rpc.portmap
fi
# Done starting the RPC portmapper.
</pre>
</td>
</tr>
</table>
<p>This can be disabled by adding <var class="LITERAL">#</var> symbols to the beginnings
of the lines that don't already start with them, like so:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="PROGRAMLISTING">
# This must be running in order to mount NFS volumes.
# Start the RPC portmapper:
#if [ -x /sbin/rpc.portmap ]; then
# echo "Starting RPC portmapper: /sbin/rpc.portmap"
# /sbin/rpc.portmap
#fi
# Done starting the RPC portmapper.
</pre>
</td>
</tr>
</table>
<p>These changes will only take effect after either a reboot or changing from and back to
runlevel 3 or 4. You can do this by typing the following on the console (you will need to
log in again after changing to runlevel 1):</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">#</samp> <kbd class="USERINPUT">telinit 1</kbd>
<samp class="PROMPT">#</samp> <kbd class="USERINPUT">telinit 3</kbd>
</pre>
</td>
</tr>
</table>
</div>
</div>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="SECURITY-HOST" name="SECURITY-HOST">14.2 Host Access
Control</a></h2>
<div class="SECT2">
<h3 class="SECT2"><a id="SECURITY-HOST-IPTABLES" name="SECURITY-HOST-IPTABLES">14.2.1 <tt
class="COMMAND">iptables</tt></a></h3>
<p><tt class="COMMAND">iptables</tt> is the packet filtering configuration program for
Linux 2.4 and above. The 2.4 kernel (2.4.5, to be exact) was first introduced into
Slackware (as an option) in version 8.0 and was made the default in Slackware 8.1. This
section only covers the basics of its usage and you should check <a
href="http://www.netfilter.org/" target="_top">http://www.netfilter.org/</a> for more
details. These commands can be entered into <tt
class="FILENAME">/etc/rc.d/rc.firewall</tt>, which has to be set as executable for these
rules to take effect at startup. Note that incorrect <tt class="COMMAND">iptables</tt>
commands can essentially lock you out of your own machine. Unless you are 100% confident
in your skills, always ensure you have local access to the machine.</p>
<p>The first thing most people should do is set the default policy for each inbound chain
to DROP:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">#</samp> <kbd class="USERINPUT">iptables -P INPUT DROP</kbd>
<samp class="PROMPT">#</samp> <kbd class="USERINPUT">iptables -P FORWARD DROP</kbd>
</pre>
</td>
</tr>
</table>
<p>When everything is denied, you can start allowing things. The first thing to allow is
any traffic for sessions which are already established:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">#</samp> <kbd
class="USERINPUT">iptables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT</kbd>
</pre>
</td>
</tr>
</table>
<p>So as not to break any applications that communicate using the loopback address, it is
usually wise to add a rule like this:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">#</samp> <kbd
class="USERINPUT">iptables -A INPUT -s 127.0.0.0/8 -d 127.0.0.0/8 -i lo -j ACCEPT</kbd>
</pre>
</td>
</tr>
</table>
<p>This rules allows any traffic to and from 127.0.0.0/8 (127.0.0.0 - 127.255.255.255) on
the loopback (<tt class="FILENAME">lo</tt>) interface. When creating rules, it is a good
idea to be as specific as possible, to make sure that your rules do not inadvertently
allow anything evil. That said, rules that allow too little mean more rules and more
typing.</p>
<p>The next thing to do would be to allow access to specific services running on your
machine. If, for example, you wanted to run a web server on your machine, you would use a
rule similar to this:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">#</samp> <kbd
class="USERINPUT">iptables -A INPUT -p tcp --dport 80 -i ppp0 -j ACCEPT</kbd>
</pre>
</td>
</tr>
</table>
<p>This will allow access from any machine to port 80 on your machine via the <tt
class="FILENAME">ppp0</tt> interface. You may want to restrict access to this service so
that only certain machines can access it. This rule allows access to your web service
from <tt class="HOSTID">64.57.102.34</tt>:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">#</samp> <kbd
class="USERINPUT">iptables -A INPUT -p tcp -s 64.57.102.34 --dport 80 -i ppp0 -j ACCEPT</kbd>
</pre>
</td>
</tr>
</table>
<p>Allowing ICMP traffic can be useful for diagnostic purposes. To do this, you would use
a rule like this:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">#</samp> <kbd
class="USERINPUT">iptables -A INPUT -p icmp -j ACCEPT</kbd>
</pre>
</td>
</tr>
</table>
<p>Most people will also want to set up Network Address Translation (NAT) on their
gateway machine, so that other machines on their network can access the Internet through
it. You would use the following rule to do this:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">#</samp> <kbd
class="USERINPUT">iptables -t nat -A POSTROUTING -o ppp0 -j MASQUERADE</kbd>
</pre>
</td>
</tr>
</table>
<p>You will also need to enable IP forwarding. You can do this temporarily, using the
following command:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">#</samp> <kbd
class="USERINPUT">echo 1 > /proc/sys/net/ipv4/ip_forward</kbd>
</pre>
</td>
</tr>
</table>
<p>To enable IP forwarding on a more permanent basis (i.e. so that the change is kept
after a reboot), you will need to open the file <tt
class="FILENAME">/etc/rc.d/rc.inet2</tt> in your favorite editor and change the following
line:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="PROGRAMLISTING">
IPV4_FORWARD=0
</pre>
</td>
</tr>
</table>
<p>...to this:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="PROGRAMLISTING">
IPV4_FORWARD=1
</pre>
</td>
</tr>
</table>
<p>For more information on NAT, see the <a
href="http://www.netfilter.org/documentation/HOWTO/NAT-HOWTO.txt" target="_top">NAT
HOWTO</a>.</p>
</div>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="SECURITY-HOST-TCPWRAPPERS"
name="SECURITY-HOST-TCPWRAPPERS">14.2.2 <tt class="COMMAND">tcpwrappers</tt></a></h3>
<p><tt class="COMMAND">tcpwrappers</tt> controls access to daemons at the application
level, rather than at the IP level. This can provide an extra layer of security at times
when IP-level access controls (e.g. Netfilter) are not functioning correctly. For
example, if you recompile the kernel but forget to include iptables support, your IP
level protection will fail but tcpwrappers will still help protect your system.</p>
<p>Access to services protected by tcpwrappers can be controlled using <tt
class="FILENAME">/etc/hosts.allow</tt> and <tt class="FILENAME">/etc/hosts.deny</tt>.</p>
<p>The majority of people would have a single line in their <tt
class="FILENAME">/etc/hosts.deny</tt> file to deny access to all daemons by default. This
line would be:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="PROGRAMLISTING">
ALL : ALL
</pre>
</td>
</tr>
</table>
<p>When this is done, you can concentrate on allowing access to services for specified
hosts, domains, or IP ranges. This can be done in the <tt
class="FILENAME">/etc/hosts.allow</tt> file, which follows the same format.</p>
<p>A lot of people would start by accepting all connections from <tt
class="HOSTID">localhost</tt>. This can be achieved using:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="PROGRAMLISTING">
ALL : 127.0.0.1
</pre>
</td>
</tr>
</table>
<p>To allow access to SSHd from <tt class="HOSTID">192.168.0.0/24</tt>, you could use
either of the following rules:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="PROGRAMLISTING">
sshd : 192.168.0.0/24
sshd : 192.168.0.
</pre>
</td>
</tr>
</table>
<p>It is also possible to restrict access to hosts in certain domains. This can be done
using the following rule (note that this relies on the reverse DNS entry for the
connecting host being trustworthy, so I would recommand against its use on
Internet-connected hosts):</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="PROGRAMLISTING">
sshd : .slackware.com
</pre>
</td>
</tr>
</table>
</div>
</div>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="SECURITY-CURRENT" name="SECURITY-CURRENT">14.3 Keeping
Current</a></h2>
<div class="SECT2">
<h3 class="SECT2"><a id="SECURITY-CURRENT-LIST" name="SECURITY-CURRENT-LIST">14.3.1 <var
class="LITERAL">slackware-security</var> mailing list</a></h3>
<p>Whenever a security problem affects Slackware, an email is sent to all subscribers to
the <var class="LITERAL">slackware-security@slackware.com</var> mailing list. Reports are
sent out for vulnerabilities of any part of Slackware, apart from the software in <tt
class="FILENAME">/extra</tt> or <tt class="FILENAME">/pasture</tt>. These security
announcement emails include details on obtaining updated versions of Slackware packages
or work-arounds, if any.</p>
<p>Subscribing to Slackware mailing lists is covered in <a
href="#HELP-ONLINE-EMAIL">Section 2.2.2</a>.</p>
</div>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="SECURITY-CURRENT-PATCHES" name="SECURITY-CURRENT-PATCHES">14.3.2
The <tt class="FILENAME">/patches</tt> directory</a></h3>
<p>Whenever updated packages are released for a version of Slackware (usually only to fix
a security problem, in the case of already released Slackware versions), they are placed
in the <tt class="FILENAME">/patches</tt> directory. The full path to these patches will
depend on the mirror you are using, but will take the form <tt
class="FILENAME">/path/to/slackware-x.x/patches/</tt>.</p>
<p>Before installing these packages, it is a good idea to verify the <tt
class="COMMAND">md5sum</tt> of the package. <tt class="COMMAND">md5sum</tt>(1) is a
commandline utility that creates a “unique” mathematical hash of the file. If
a single bit of the file has been changed, it will generate a different md5sum value.</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd
class="USERINPUT">md5sum package-<ver>-<arch>-<rev>.tgz</kbd>
6341417aa1c025448b53073a1f1d287d package-<ver>-<arch>-<rev>.tgz
</pre>
</td>
</tr>
</table>
<p>You should then check this against the line for the new package in the <tt
class="FILENAME">CHECKSUMS.md5</tt> file in the root of the <tt
class="FILENAME">slackware-<var class="REPLACEABLE">$VERSION</var></tt> directory (also
in the <tt class="FILENAME">/patches</tt> directory for patches) or in the email to the
<var class="LITERAL">slackware-security</var> mailing list.</p>
<p>If you have a file with the md5sum values in it, you can source it instead with the
<var class="OPTION">-c</var> option to <tt class="COMMAND">md5sum</tt>.</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">#</samp> <kbd class="USERINPUT">md5sum -c CHECKSUMS.md5</kbd>
./ANNOUNCE.10_0: OK
./BOOTING.TXT: OK
./COPYING: OK
./COPYRIGHT.TXT: OK
./CRYPTO_NOTICE.TXT: OK
./ChangeLog.txt: OK
./FAQ.TXT: FAILED
</pre>
</td>
</tr>
</table>
<p>As you can see, any files that <tt class="COMMAND">md5sum</tt> evaluates as correct
are listed “<var class="LITERAL">OK</var>” while files that fail are labelled
“<var class="LITERAL">FAILED</var>”. (Yes, this was an insult to your
intelligence. Why do you put up with me?)</p>
</div>
</div>
</div>
<div class="CHAPTER">
<hr />
<h1><a id="ARCHIVE-FILES" name="ARCHIVE-FILES"></a>Chapter 15 Archive Files</h1>
<div class="SECT1">
<h2 class="SECT1"><a id="ARCHIVE-FILES-GZIP" name="ARCHIVE-FILES-GZIP">15.1 <tt
class="COMMAND">gzip</tt></a></h2>
<p><tt class="COMMAND">gzip</tt>(1) is the GNU compression program. It takes a single
file and compresses it. The basic usage is as follows:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">gzip <var
class="REPLACEABLE">filename</var></kbd>
</pre>
</td>
</tr>
</table>
<p>The resulting file will be named <tt class="FILENAME"><var
class="REPLACEABLE">filename</var>.gz</tt> and will usually be smaller than the input
file. Note that <tt class="FILENAME">filename.gz</tt> will replace <tt
class="FILENAME">filename</tt>. This means that <tt class="FILENAME">filename</tt> will
no longer exist, even though a gzipped copy will. Regular text files will compress
nicely, while jpeg images, mp3s, and other such files will not compress too well as they
are already compressed. This basic usage is a balance of final file size and compression
time. The maximum compression can be achieved like so:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">gzip -9 <var
class="REPLACEABLE">filename</var></kbd>
</pre>
</td>
</tr>
</table>
<p>This will take a longer time to compress the file, but the result will be as small as
<tt class="COMMAND">gzip</tt> can make it. Using lower values for the command line option
will cause it to compress faster, but the file will not be as compressed.</p>
<p>Decompressing gzipped files can be done using two commands, which are really just the
same program. <tt class="COMMAND">gzip</tt> will decompress any file with a recognized
file extension. A recognized extension can be any of the following: <tt
class="FILENAME">.gz</tt>, <tt class="FILENAME">-gz</tt>, <tt class="FILENAME">.z</tt>,
<tt class="FILENAME">-z</tt>, <tt class="FILENAME">.Z</tt>, or <tt
class="FILENAME">-Z</tt>. The first method is to call <tt class="COMMAND">gunzip</tt>(1)
on a file, like so:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">gunzip <var
class="REPLACEABLE">filename.gz</var></kbd>
</pre>
</td>
</tr>
</table>
<p>This will leave a decompressed version of infile in the current directory, and the <tt
class="FILENAME">.gz</tt> extension will be stripped from the filename. <tt
class="COMMAND">gunzip</tt> is really part of <tt class="COMMAND">gzip</tt> and is
identical to <tt class="COMMAND">gzip -d</tt>. As such, <tt class="COMMAND">gzip</tt> is
often pronounced <tt class="COMMAND">gunzip</tt>, as that name just sounds cooler.
:^)</p>
</div>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="ARCHIVE-FILES-BZIP2" name="ARCHIVE-FILES-BZIP2">15.2 <tt
class="COMMAND">bzip2</tt></a></h2>
<p><tt class="COMMAND">bzip2</tt>(1) is an alternative compression program installed on
Slackware Linux. It uses a different compression algorithm from <tt
class="COMMAND">gzip</tt>, which results in some advantages and some disadvantages. The
main advantage for <tt class="COMMAND">bzip2</tt> is the compressed file size. <tt
class="COMMAND">bzip2</tt> will almost always compress better than <tt
class="COMMAND">gzip</tt>. In some instances, this can result in dramatically smaller
files. This can be a great advantage for people on slower modem connections. Also
remember, when downloading software from a public ftp server, it's generally good
netiquette to download the <tt class="FILENAME">.bz2</tt> files instead of the <tt
class="FILENAME">.gz</tt> files, as this results in less overhead for the generous people
hosting the server.</p>
<p>The disadvantage to <tt class="COMMAND">bzip2</tt> is that it is more CPU intensive
than <tt class="COMMAND">gzip</tt>. This means that bzipping a file will generally take
longer and will use more of the CPU than gzipping the file would. When considering which
compression program to use, you must weigh this speed vs. compressed size and determine
which is more important.</p>
<p>The usage of <tt class="COMMAND">bzip2</tt> is nearly identical to <tt
class="COMMAND">gzip</tt>, so not much time will be spent discussing it. Like <tt
class="COMMAND">gunzip</tt>, <tt class="COMMAND">bunzip2</tt> is identical to <tt
class="COMMAND">bzip2 -d</tt>. The primary difference in practical usage is that <tt
class="COMMAND">bzip2</tt> uses the <tt class="FILENAME">.bz2</tt> extension.</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">bzip2 <var
class="REPLACEABLE">filename</var></kbd>
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">bunzip2 <var
class="REPLACEABLE">filename.bz2</var></kbd>
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">bzip2 -9 <var
class="REPLACEABLE">filename</var></kbd>
</pre>
</td>
</tr>
</table>
</div>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="ARCHIVE-FILES-TAR" name="ARCHIVE-FILES-TAR">15.3 <tt
class="COMMAND">tar</tt></a></h2>
<p><tt class="COMMAND">tar</tt>(1) is the GNU tape archiver. It takes several files or
directories and creates one large file. This allows you to compress an entire directory
tree, which is impossible by just using <tt class="COMMAND">gzip</tt> or <tt
class="COMMAND">bzip2</tt>. <tt class="COMMAND">tar</tt> has many command line options,
which are explained in its man page. This section will just cover the most common uses of
<tt class="COMMAND">tar</tt>.</p>
<p>The most common use for <tt class="COMMAND">tar</tt> is to decompress and unarchive a
package that you've downloaded from a web site or ftp site. Most files will come with a
<tt class="FILENAME">.tar.gz</tt> extension. This is commonly known as a
“tarball”. It means that several files were archived using <tt
class="COMMAND">tar</tt> and then compressed using <tt class="COMMAND">gzip</tt>. You
might also see this listed as a <tt class="FILENAME">.tar.Z</tt> file. It means the same
thing, but this is usually encountered on older Unix systems.</p>
<p>Alternatively, you might find a <tt class="FILENAME">.tar.bz2</tt> file somewhere.
Kernel source is distributed as such because it is a smaller download. As you might have
guessed, this is several files archived with <tt class="COMMAND">tar</tt> and then
bzipped.</p>
<p>You can get to all the files in this archive by making use of <tt
class="COMMAND">tar</tt> and some command line arguments. Unarchiving a tarball makes use
of the <var class="OPTION">-z</var> flag, which means to first run the file through <tt
class="COMMAND">gunzip</tt> and decompress it. The most common way to decompress a
tarball is like so:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">tar -xvzf filename.tar.gz</kbd>
</pre>
</td>
</tr>
</table>
<p>That's quite a few options. So what do they all mean? The <var class="OPTION">-x</var>
means to extract. This is important, as it tells <tt class="COMMAND">tar</tt> exactly
what to do with the input file. In this case, we'll be splitting it back up into all the
files that it came from. <var class="OPTION">-v</var> means to be verbose. This will list
all the files that are being unarchived. It is perfectly acceptable to leave this option
off, if somewhat boring. Alternatively, you could use <var class="OPTION">-vv</var> to be
very verbose and list even more information about each file being unarchived. The <var
class="OPTION">-z</var> option tells <tt class="COMMAND">tar</tt> to run <tt
class="FILENAME">filename.tar.gz</tt> through <tt class="COMMAND">gunzip</tt> first. And
finally, the <var class="OPTION">-f</var> option tells <tt class="COMMAND">tar</tt> that
the next string on the command line is the file to operate on.</p>
<p>There are a few other ways to write this same command. On older systems lacking a
decent copy of GNU <tt class="COMMAND">tar</tt>, you might see it written like so:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd
class="USERINPUT">gunzip filename.tar.gz | tar -xvf -</kbd>
</pre>
</td>
</tr>
</table>
<p>This command line will uncompress the file and send the output to <tt
class="COMMAND">tar</tt>. Since <tt class="COMMAND">gzip</tt> will write its output to
standard out if told to do so, this command will write the decompressed file to standard
out. The pipe then sends it to <tt class="COMMAND">tar</tt> for unarchiving. The
“-” means to operate on standard input. It will unarchive the stream of data
that it gets from <tt class="COMMAND">gzip</tt> and write that to the disk.</p>
<p>Another way to write the first command line is to leave off the dash before the
options, like so:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">tar xvzf filename.tar.gz</kbd>
</pre>
</td>
</tr>
</table>
<p>You might also encounter a bzipped archive. The version of <tt
class="COMMAND">tar</tt> that comes with Slackware Linux can handle these the same as
gzipped archives. Instead of the <var class="OPTION">-z</var> command line option, you'd
use <var class="OPTION">-j</var>:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">tar -xvjf filename.tar.bz2</kbd>
</pre>
</td>
</tr>
</table>
<p>It is important to note that <tt class="COMMAND">tar</tt> will place the unarchived
files in the current directory. So, if you had an archive in <tt
class="FILENAME">/tmp</tt> that you wanted to decompress into your home directory, there
are a few options. First, the archive could be moved into your home directory and then
run through <tt class="COMMAND">tar</tt>. Second, you could specify the path to the
archive file on the command line. Third, you can use the <var class="OPTION">-C</var>
option to “explode” the tarball in a specified directory.</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">cd $HOME</kbd>
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">cp /tmp/filename.tar.gz .</kbd>
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">tar -xvzf filename.tar.gz</kbd>
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">cd $HOME</kbd>
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">tar -xvzf /tmp/filename.tar.gz</kbd>
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">cd /</kbd>
<samp class="PROMPT">%</samp> <kbd
class="USERINPUT">tar -xvzf /tmp/filename.tar.gz -C $HOME</kbd>
</pre>
</td>
</tr>
</table>
<p>All the above statements are equivalent. In each case, the archive is unpacked inside
your home directory and the original uncompressed archive is left in place.</p>
<p>So what good is being able to uncompress these archives if you can't make them? Well,
<tt class="COMMAND">tar</tt> handles that too. In most cases it's as easy as removing the
“<var class="OPTION">-x</var>” option and replacing it with the “<var
class="OPTION">-c</var>” option.</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">tar -cvzf filename.tar.gz .</kbd>
</pre>
</td>
</tr>
</table>
<p>In this command line, the <var class="OPTION">-c</var> option tells <tt
class="COMMAND">tar</tt> to create an archive, while the <var class="OPTION">-z</var>
option runs the resulting archive file through <tt class="COMMAND">gzip</tt> to compress
it. <tt class="FILENAME">filename.tar.gz</tt> is the file that you want to create.</p>
<p>Specifying the “<var class="OPTION">-f</var>” option isn't always
necessary, but is typically good practice anyway. Without it, <tt
class="COMMAND">tar</tt> writes to standard output, which is usually desired for piping
<tt class="COMMAND">tar</tt>'s output to another program, like so.</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd
class="USERINPUT">tar -cv filename.tar . | gpg --encrypt</kbd>
</pre>
</td>
</tr>
</table>
<p>That command creates an non-compressed tar archive of the current directory, pipes the
tarball through <tt class="COMMAND">gpg</tt> which encrypts and compresses the tarball,
making it realistically impossible to read by anyone other than the person knowing the
secret key.</p>
</div>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="ARCHIVE-FILES-ZIP" name="ARCHIVE-FILES-ZIP">15.4 <tt
class="COMMAND">zip</tt></a></h2>
<p>Finally, there are two utilities that can be used on zip files. These are very common
in the Windows world, so Linux has programs to deal with them. The compression program is
called <tt class="COMMAND">zip</tt>(1), and the decompression program is called <tt
class="COMMAND">unzip</tt>(1).</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">zip foo *</kbd>
</pre>
</td>
</tr>
</table>
<p>This will create the file <tt class="FILENAME">foo.zip</tt>, which will contain all
the files in the current directory. <tt class="COMMAND">zip</tt> will add the <tt
class="FILENAME">.zip</tt> extension automatically, so there's no need to include that in
the file name. You can also recurse through the current directory, zipping up any
directories that are also laying around:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">zip -r foo *</kbd>
</pre>
</td>
</tr>
</table>
<p>Decompressing files is easy, as well.</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">unzip foo.zip</kbd>
</pre>
</td>
</tr>
</table>
<p>This will extract all the files in the file <tt class="FILENAME">foo.zip</tt>,
including any directories in the archive.</p>
<p>The <tt class="COMMAND">zip</tt> utilities have several advanced options for creating
self-extracting archives, leaving out files, controlling compressed file size, printing
out what will happen, and much more. See the man pages for <tt class="COMMAND">zip</tt>
and <tt class="COMMAND">unzip</tt> to find out how to use these options.</p>
</div>
</div>
<div class="CHAPTER">
<hr />
<h1><a id="VI" name="VI"></a>Chapter 16 Vi</h1>
<p><tt class="COMMAND">vi</tt>(1) is the standard Unix text editing program, and while
mastering it is not as essential as it once was, is still a very rewarding goal. There
are several versions (or clones) of <tt class="COMMAND">vi</tt> available, including <tt
class="COMMAND">vi</tt>, <tt class="COMMAND">elvis</tt>, <tt class="COMMAND">vile</tt>,
and <tt class="COMMAND">vim</tt>. One of these is available on just about any version of
Unix, as well as on Linux. All of these versions include the same basic feature set and
commands, so learning one clone should make it easy to learn another. With the variety of
text editors included with Linux distributions and Unix variants these days, many people
no longer use <tt class="COMMAND">vi</tt>. Still, it remains the most universal text
editor across Unix and Unix work-alikes. Mastering <tt class="COMMAND">vi</tt> means you
should never be sitting at a Unix machine and not be comfortable with at least one
powerful text editor.</p>
<p><tt class="COMMAND">vi</tt> includes a number of powerful features including syntax
highlighting, code formatting, a powerful search-and-replace mechanism, macros, and more.
These features make it especially attractive to programmers, web developers, and the
like. System administrators will appreciate the automation and integration with the shell
that is possible.</p>
<p>On Slackware Linux, the default version of <tt class="COMMAND">vi</tt> available is
<tt class="COMMAND">elvis</tt>. Other versions - including <tt class="COMMAND">vim</tt>
and <tt class="COMMAND">gvim</tt> - are available if you've installed the proper
packages. <tt class="COMMAND">gvim</tt> is an X Window version of <tt
class="COMMAND">vim</tt> that includes toolbars, detachable menus, and dialog boxes.</p>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="VI-STARTING" name="VI-STARTING">16.1 Starting vi</a></h2>
<p><tt class="COMMAND">vi</tt> can be started from the command line in a variety of ways.
The simplest form is just:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">vi</kbd>
</pre>
</td>
</tr>
</table>
<div class="FIGURE"><a id="FIG-VI-VIM-SPLITEDIT" name="FIG-VI-VIM-SPLITEDIT"></a>
<p><b>Figure 16-1. A vi session.</b></p>
<p><img src="vi/vim-splitedit.png" /></p>
</div>
<p>This will start up <tt class="COMMAND">vi</tt> with an empty buffer. At this point,
you'll see a mostly blank screen. It is now in “command mode”, waiting for
you to do something. For a discussion of the various <tt class="COMMAND">vi</tt> modes,
see the <a href="#VI-MODES">Section 16.2</a>. In order to quit out of <tt
class="COMMAND">vi</tt>, type the following:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<kbd class="USERINPUT">:q</kbd>
</pre>
</td>
</tr>
</table>
<p>Assuming that there have been no changes to the file, this will cause <tt
class="COMMAND">vi</tt> to quit. If there have been changes made, it will warn you that
there have been changes and tell you how to disregard them. Disregarding changes usually
means appending an exclamation point after the “<b class="KEYCAP">q</b>” like
so:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<kbd class="USERINPUT">:q!</kbd>
</pre>
</td>
</tr>
</table>
<p>The exclamation point usually means to force some action. We'll discuss it and other
key combinations in further details later.</p>
<p>You can also start <tt class="COMMAND">vi</tt> with a pre-existing file. For example,
the file <tt class="FILENAME">/etc/resolv.conf</tt> would be opened like so:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">vi /etc/resolv.conf</kbd>
</pre>
</td>
</tr>
</table>
<p>Finally, <tt class="COMMAND">vi</tt> can be started on a particular line of a file.
This is especially useful for programmers when an error message includes the line their
program bombed on. For example, you could start up <tt class="COMMAND">vi</tt> on line 47
of <tt class="FILENAME">/usr/src/linux/init/main.c</tt> like so:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd
class="USERINPUT">vi +47 /usr/src/linux/init/main.c</kbd>
</pre>
</td>
</tr>
</table>
<p><tt class="COMMAND">vi</tt> will display the given file and will place the cursor at
the specified line. In the case where you specify a line that is after the end of the
file, <tt class="COMMAND">vi</tt> will place the cursor on the last line. This is
especially helpful for programmers, as they can jump straight to the location in the file
that an error occurred, without having to search for it.</p>
</div>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="VI-MODES" name="VI-MODES">16.2 Modes</a></h2>
<p><tt class="COMMAND">vi</tt> operates in various modes, which are used to accomplish
various tasks. When you first start <tt class="COMMAND">vi</tt>, you are placed into
command mode. From this point, you can issue various commands to manipulate text, move
around in the file, save, quit, and change modes. Editing the text is done in insert
mode. You can quickly move between modes with a variety of keystrokes, which are
explained below.</p>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="VI-MODES-COMMAND-MODE" name="VI-MODES-COMMAND-MODE">16.2.1
Command Mode</a></h3>
<p>You are first placed into command mode. From this mode, you cannot directly enter text
or edit what is already there. However, you can manipulate the text, search, quit, save,
load new files, and more. This is intended only to be an introduction to the command
mode. For a description of the various commands, see <a href="#VI-KEYS">Section
16.7</a>.</p>
<p>Probably the most often used command in command mode is changing to insert mode. This
is accomplished by hitting the <b class="KEYCAP">i</b> key. The cursor changes shapes,
and <span class="emphasis"><i class="EMPHASIS">-- INSERT --</i></span> is displayed at
the bottom of the screen (note that this does not happen in all clones of <tt
class="COMMAND">vi</tt>). From there, all your keystrokes are entered into the current
buffer and are displayed to the screen. To get back into command mode, hit the <b
class="KEYCAP">ESCAPE</b> key.</p>
<p>Command mode is also where you move around in the file. On some systems, you can use
the arrow keys to move around. On other systems, you may need to use the more traditional
keys of “<b class="KEYCAP">hjkl</b>”. Here is a simple listing of how these
keys are used to move around:</p>
<div class="INFORMALTABLE"><a id="AEN5604" name="AEN5604"></a>
<table border="0" frame="void" width="100%" class="CALSTABLE">
<col width="25%" />
<col width="75%" />
<tbody>
<tr>
<td><b class="KEYCAP">h</b></td>
<td>move left one character</td>
</tr>
<tr>
<td><b class="KEYCAP">j</b></td>
<td>move down one character</td>
</tr>
<tr>
<td><b class="KEYCAP">k</b></td>
<td>move up one character</td>
</tr>
<tr>
<td><b class="KEYCAP">l</b></td>
<td>move right one character</td>
</tr>
</tbody>
</table>
</div>
<p>Simply press a key to move. As you will see later, these keys can be combined with a
number to move much more efficiently.</p>
<p>Many of the commands that you will use in command mode begin with a colon. For
example, quitting is <b class="KEYCAP">:q</b>, as discussed earlier. The colon simply
indicates that it is a command, while the “<b class="KEYCAP">q</b>” tells <tt
class="COMMAND">vi</tt> to quit. Other commands are an optional number, followed by a
letter. These commands do not have a colon before them, and are generally used to
manipulate the text.</p>
<p>For example, deleting one line from a file is accomplished by hitting <b
class="KEYCAP">dd</b>. This will remove the line that the cursor is on. Issuing the
command <b class="KEYCAP">4dd</b> would tell <tt class="COMMAND">vi</tt> to remove the
line that the cursor is on and the three after that. In general, the number tells <tt
class="COMMAND">vi</tt> how many times to perform the command.</p>
<p>You can combine a number with the movement keys to move around several characters at a
time. For example, <b class="KEYCAP">10k</b> would move up ten lines on the screen.</p>
<p>Command mode can also be used to cut and paste, insert text, and read other files into
the current buffer. Copying text is accomplished with the <b class="KEYCAP">y</b> key (<b
class="KEYCAP">y</b> stands for yank). Copying the current line is done by typing <b
class="KEYCAP">yy</b>, and this can be prefixed with a number to yank more lines. Then,
move to the location for the copy and hit <b class="KEYCAP">p</b>. The text is pasted on
the line after the current one.</p>
<p>Cutting text is done by typing <b class="KEYCAP">dd</b>, and <b class="KEYCAP">p</b>
can be used to paste the cut text back into the file. Reading in text from another file
is a simple procedure. Just type <b class="KEYCAP">:r</b>, followed by a space and the
file name that contains the text to be inserted. The file's contents will be pasted into
the current buffer on the line after the cursor. More sophisticated <tt
class="COMMAND">vi</tt> clones even contain filename completion similar to the
shell's.</p>
<p>The final use that will be covered is searching. Command mode allows for simple
searching, as well as complicated search-and-replace commands that make use of a powerful
version of regular expressions. A complete discussion of regular expressions is beyond
the scope of this chapter, so this section will only cover simple means of searching.</p>
<p>A simple search is accomplished by hitting the <b class="KEYCAP">/</b> key, followed
by the text that you are searching for. <tt class="COMMAND">vi</tt> will search forward
from the cursor to the end of the file for a match, stopping when it finds one. Note that
inexact matches will cause <tt class="COMMAND">vi</tt> to stop as well. For example, a
search for “<span class="emphasis"><i class="EMPHASIS">the</i></span>” will
cause <tt class="COMMAND">vi</tt> to stop on “<span class="emphasis"><i
class="EMPHASIS">then</i></span>”, “<span class="emphasis"><i
class="EMPHASIS">therefore</i></span>”, and so on. This is because all of those
words do match “<span class="emphasis"><i
class="EMPHASIS">the</i></span>”.</p>
<p>After <tt class="COMMAND">vi</tt> has found the first match, you can continue on to
the next match simply by hitting the <b class="KEYCAP">/</b> key followed by enter. You
can also search backwards through the file by replacing the slash with the <b
class="KEYCAP">?</b> key. For example, searching backwards through the file for
“<span class="emphasis"><i class="EMPHASIS">the</i></span>” would be
accomplished by typing <b class="KEYCAP">?the</b>.</p>
</div>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="VI-MODES-INSET-MODE" name="VI-MODES-INSET-MODE">16.2.2 Insert
Mode</a></h3>
<p>Inserting and replacing text is accomplished in insert mode. As previously discussed,
you can get into insert mode by hitting <b class="KEYCAP">i</b> from command mode. Then,
all text that you type is entered into the current buffer. Hitting the <b
class="KEYCAP">ESCAPE</b> key takes you back into command mode.</p>
<p>Replacing text is accomplished in several ways. From command mode, hitting <b
class="KEYCAP">r</b> will allow you to replace the one character underneath the cursor.
Just type the new character and it will replace the one under the cursor. You will then
be immediately placed back into command mode. Hitting <b class="KEYCAP">R</b> allows you
to replace as many characters as you'd like. To get out of this replacement mode, just
hit <b class="KEYCAP">ESCAPE</b> to go back into command mode.</p>
<p>There is yet another way to toggle between insertion and replacement. Hitting the <b
class="KEYCAP">INSERT</b> key from command mode will take you into insert mode. Once you
are in insert mode, the keyboard's <b class="KEYCAP">INSERT</b> key serves as a toggle
between insert and replace. Hitting it once will allow you to replace. Hitting it once
more will once again allow you to insert text.</p>
</div>
</div>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="VI-OPENING-FILES" name="VI-OPENING-FILES">16.3 Opening
Files</a></h2>
<p><tt class="COMMAND">vi</tt> allows you to open files from command mode as well as
specifying a file on the command line to open. To open the file <tt
class="FILENAME">/etc/lilo.conf</tt>:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<kbd class="USERINPUT">:e /etc/lilo.conf</kbd>
</pre>
</td>
</tr>
</table>
<p>If you have made changes to the current buffer without saving, <tt
class="COMMAND">vi</tt> will complain. You can still open the file without saving the
current buffer by typing <b class="KEYCAP">:e!</b>, followed by a space and the filename.
In general, <tt class="COMMAND">vi</tt>'s warnings can be suppressed by following the
command with an exclamation mark.</p>
<p>If you want to reopen the current file, you can do so simply by typing <b
class="KEYCAP">e!</b>. This is particularly useful if you have somehow messed up the file
and want to reopen it.</p>
<p>Some <tt class="COMMAND">vi</tt> clones (for example, <tt class="COMMAND">vim</tt>)
allow for multiple buffers to be open at the same time. For example, to open up the file
<tt class="FILENAME">09-vi.sgml</tt> in my home directory while another file was open, I
would type:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<kbd class="USERINPUT">:split ~/09-vi.sgml</kbd>
</pre>
</td>
</tr>
</table>
<p>The new file is displayed on the top half of the screen, and the old file is displayed
in the bottom half of the screen. There are a lot of commands that manipulate the split
screen, and many of these commands start to resemble something out of <tt
class="COMMAND">Emacs</tt> The best place to look up these commands would be the man page
for your vi clone. Note that many clones do not support the split-screen idea, so you
might not be able to use it at all.</p>
</div>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="VI-SAVING-FILES" name="VI-SAVING-FILES">16.4 Saving
Files</a></h2>
<p>There are several ways to save files in <tt class="COMMAND">vi</tt>. If you want to
save the current buffer to the file <tt class="FILENAME">randomness</tt>, you would
type:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<kbd class="USERINPUT">:w randomness</kbd>
</pre>
</td>
</tr>
</table>
<p>Once you've saved the file once, saving it again is as simple as typing <b
class="KEYCAP">:w</b>. Any changes will be written out to the file. After you've saved
the file, you are dumped back into command mode. If you want to save the file and quit
<tt class="COMMAND">vi</tt> (a very common operation), you would type <b
class="KEYCAP">:wq</b>. That tells <tt class="COMMAND">vi</tt> to save the current file
and quit back to the shell.</p>
<p>On occasion, you want to save a file that is marked as read-only. You can do this by
adding an exclamation point after the write command, like so:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<kbd class="USERINPUT">:w!</kbd>
</pre>
</td>
</tr>
</table>
<p>However, there will still be instances where you cannot write the file (for example,
you are attempting to edit a file that is owned by another user). When this happens, <tt
class="COMMAND">vi</tt> will tell you that it cannot save the file. If you really want to
edit the file, you'll have to come back and edit it as <tt class="USERNAME">root</tt> or
(preferably) the owner of that file.</p>
</div>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="VI-QUITTING-VI" name="VI-QUITTING-VI">16.5 Quitting vi</a></h2>
<p>One way to quit <tt class="COMMAND">vi</tt> is through <b class="KEYCAP">:wq</b>,
which will save the current buffer before quitting. You can also quit without saving with
<b class="KEYCAP">:q</b> or (more commonly) <b class="KEYCAP">:q!</b>. The latter is used
when you've modified the file but do not wish to save any changes to it.</p>
<p>On occasion, your machine might crash or <tt class="COMMAND">vi</tt> might crash.
However, both <tt class="COMMAND">elvis</tt> and <tt class="COMMAND">vim</tt> will take
steps to minimize the damage to any open buffers. Both editors save the open buffers to a
temporary file on occasion. This file is usually named similarly to the open file, but
with a dot at the beginning. This makes the file hidden.</p>
<p>This temporary file gets removed once the editor quits under normal conditions. This
means that the temporary copy will still be around if something crashes. When you go back
to edit the file again, you will be prompted for what action to take. In most cases, a
large amount of your unsaved work can be recovered. <tt class="COMMAND">elvis</tt> will
also send you a mail (from Graceland, oddly enough :) telling you that a backup copy
exists.</p>
</div>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="VI-CONFIGURATION" name="VI-CONFIGURATION">16.6 vi
Configuration</a></h2>
<p>Your <tt class="COMMAND">vi</tt> clone of choice can be configured in several
ways.</p>
<p>A variety of commands can be entered while in command mode to set up <tt
class="COMMAND">vi</tt> just how you like it. Depending on your editor, you can enable
features to make programming easier (like syntax hilighting, auto-indenting, and more),
set up macros to automake tasks, enable textual substitutions, and more.</p>
<p>Almost all of these commands can be put into a configuration file in your home
directory. <tt class="COMMAND">elvis</tt> expects a <tt class="FILENAME">.exrc</tt> file,
while <tt class="COMMAND">vim</tt> expects a <tt class="FILENAME">.vimrc</tt> file. Most
of the setup commands that can be entered in command mode can be placed in the
configuration file. This includes setup information, textual substitutions, macros, and
more.</p>
<p>Discussing all these options and the differences between the editors is quite an
involved subject. For more information, check out the man page or web site for your
preferred <tt class="COMMAND">vi</tt> editor. Some editors (like <tt
class="COMMAND">vim</tt>) have extensive help within the editor that can be accessed with
the <b class="KEYCAP">:help</b> command, or something similar. You can also check out the
O'Reilly book <i class="CITETITLE">Learning the <tt class="COMMAND">vi</tt> Editor</i> by
Lamb and Robbins.</p>
<p>Many common programs in Linux will load up a text file in <tt class="COMMAND">vi</tt>
by default. For example, editing your crontabs will start up <tt class="COMMAND">vi</tt>
by default. If you do not like <tt class="COMMAND">vi</tt> and would like another editor
to be started instead, all you need to do is set the <tt class="ENVAR">VISUAL</tt>
environment variable to the editor you prefer. For information on setting environment
variables, see the section called Environment Variables in Chapter 8. If you want to make
sure that your editor will be the default every time you login, add the VISUAL setting to
your <tt class="FILENAME">.bash_profile</tt> or <tt class="FILENAME">.bashrc</tt>
files.</p>
</div>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="VI-KEYS" name="VI-KEYS">16.7 Vi Keys</a></h2>
<p>This section is a quick reference of many common <tt class="COMMAND">vi</tt> commands.
Some of these were discussed earlier in the chapter, while many will be new.</p>
<div class="TABLE"><a id="AEN5773" name="AEN5773"></a>
<p><b>Table 16-1. Movement</b></p>
<table border="0" frame="void" class="CALSTABLE">
<col />
<col />
<thead>
<tr>
<th align="CENTER">Operation</th>
<th align="CENTER">Key</th>
</tr>
</thead>
<tbody>
<tr>
<td>left, down, up, right</td>
<td align="CENTER"><b class="KEYCAP">h</b>, <b class="KEYCAP">j</b>, <b
class="KEYCAP">k</b>, <b class="KEYCAP">l</b></td>
</tr>
<tr>
<td>To the end of the line</td>
<td align="CENTER"><b class="KEYCAP">$</b></td>
</tr>
<tr>
<td>To the beginning of the line</td>
<td align="CENTER"><b class="KEYCAP">^</b></td>
</tr>
<tr>
<td>To the end of the file</td>
<td align="CENTER"><b class="KEYCAP">G</b></td>
</tr>
<tr>
<td>To the beginning of the file</td>
<td align="CENTER"><b class="KEYCAP">:1</b></td>
</tr>
<tr>
<td>To line 47</td>
<td align="CENTER"><b class="KEYCAP">:47</b></td>
</tr>
</tbody>
</table>
</div>
<div class="TABLE"><a id="AEN5808" name="AEN5808"></a>
<p><b>Table 16-2. Editing</b></p>
<table border="0" frame="void" class="CALSTABLE">
<col />
<col />
<thead>
<tr>
<th align="CENTER">Operation</th>
<th align="CENTER">Key</th>
</tr>
</thead>
<tbody>
<tr>
<td>Removing a line</td>
<td align="CENTER"><b class="KEYCAP">dd</b></td>
</tr>
<tr>
<td>Removing five lines</td>
<td align="CENTER"><b class="KEYCAP">5dd</b></td>
</tr>
<tr>
<td>Replacing a character</td>
<td align="CENTER"><b class="KEYCAP">r</b></td>
</tr>
<tr>
<td>Removing a character</td>
<td align="CENTER"><b class="KEYCAP">x</b></td>
</tr>
<tr>
<td>Removing ten characters</td>
<td align="CENTER"><b class="KEYCAP">10x</b></td>
</tr>
<tr>
<td>Undo last action</td>
<td align="CENTER"><b class="KEYCAP">u</b></td>
</tr>
<tr>
<td>Join current and next lines</td>
<td align="CENTER"><b class="KEYCAP">J</b></td>
</tr>
<tr>
<td>Replace old with new, globally</td>
<td align="CENTER"><b class="KEYCAP">%s'old'new'g</b></td>
</tr>
</tbody>
</table>
</div>
<div class="TABLE"><a id="AEN5848" name="AEN5848"></a>
<p><b>Table 16-3. Searching</b></p>
<table border="0" frame="void" class="CALSTABLE">
<col />
<col />
<thead>
<tr>
<th align="CENTER">Operation</th>
<th align="CENTER">Key</th>
</tr>
</thead>
<tbody>
<tr>
<td>Search for “asdf”</td>
<td align="CENTER"><b class="KEYCAP">/asdf</b></td>
</tr>
<tr>
<td>Search backwards for “asdf”</td>
<td align="CENTER"><b class="KEYCAP">?asdf</b></td>
</tr>
<tr>
<td>Repeat last search forwards</td>
<td align="CENTER"><b class="KEYCAP">/</b></td>
</tr>
<tr>
<td>Repeat last search backwards</td>
<td align="CENTER"><b class="KEYCAP">?</b></td>
</tr>
<tr>
<td>Repeat last search, same direction</td>
<td align="CENTER"><b class="KEYCAP">n</b></td>
</tr>
<tr>
<td>Repeat last search, opposite direction</td>
<td align="CENTER"><b class="KEYCAP">N</b></td>
</tr>
</tbody>
</table>
</div>
<div class="TABLE"><a id="AEN5882" name="AEN5882"></a>
<p><b>Table 16-4. Saving and Quitting</b></p>
<table border="0" frame="void" class="CALSTABLE">
<col />
<col />
<thead>
<tr>
<th align="CENTER">Operation</th>
<th align="CENTER">Key</th>
</tr>
</thead>
<tbody>
<tr>
<td>Quit</td>
<td align="CENTER"><b class="KEYCAP">:q</b></td>
</tr>
<tr>
<td>Quit without saving</td>
<td align="CENTER"><b class="KEYCAP">:q!</b></td>
</tr>
<tr>
<td>Write and quit</td>
<td align="CENTER"><b class="KEYCAP">:wq</b></td>
</tr>
<tr>
<td>Write, without quitting</td>
<td align="CENTER"><b class="KEYCAP">:w</b></td>
</tr>
<tr>
<td>Reload currently open file</td>
<td align="CENTER"><b class="KEYCAP">:e!</b></td>
</tr>
<tr>
<td>Write buffer to file <tt class="FILENAME">asdf</tt></td>
<td align="CENTER"><b class="KEYCAP">:w asdf</b></td>
</tr>
<tr>
<td>Open file <tt class="FILENAME">hejaz</tt></td>
<td align="CENTER"><b class="KEYCAP">:e hejaz</b></td>
</tr>
<tr>
<td>Read file <tt class="FILENAME">asdf</tt> into buffer</td>
<td align="CENTER"><b class="KEYCAP">:r asdf</b></td>
</tr>
<tr>
<td>Read output of <tt class="COMMAND">ls</tt> into buffer</td>
<td align="CENTER"><b class="KEYCAP">:r !ls</b></td>
</tr>
</tbody>
</table>
</div>
</div>
</div>
<div class="CHAPTER">
<hr />
<h1><a id="EMACS" name="EMACS"></a>Chapter 17 Emacs</h1>
<p>While <tt class="COMMAND">vi</tt> (with its clones) is without a doubt the most
ubiquitous editor on Unix-like systems, Emacs comes in a good second. Instead of using
different “modes”, like <tt class="COMMAND">vi</tt> does, it uses <b
class="KEYCAP">Control</b> and <b class="KEYCAP">Alt</b> key combinations to enter
commands, in much the same way that you can use <b class="KEYCAP">Control</b> and <b
class="KEYCAP">Alt</b> key combinations in a word processor and indeed in many other
applications to execute certain functions. (Though it should be noted that the commands
rarely correspond; so while many modern applications use <b class="KEYCAP">Ctrl</b>-<b
class="KEYCAP">C</b>/ <b class="KEYCAP">X</b>/ <b class="KEYCAP">V</b> for copying,
cutting and pasting, Emacs uses different keys and actually a somewhat different
mechanism for this.)</p>
<p>Also unlike <tt class="COMMAND">vi</tt>, which is an (excellent) editor and nothing
more, Emacs is a program with near endless capabilities. Emacs is (for the most part)
written in Lisp, which is a very powerful programming language that has the peculiar
property that every program written in it is automatically a Lisp compiler of its own.
This means that the user can extend Emacs, and in fact write completely new programs
“in Emacs”.</p>
<p>As a result, Emacs is not just an editor anymore. There are many add-on packages for
Emacs available (many come with the program's source) that provide all sorts of
functionality. Many of these are related to text editing, which is after all Emacs' basic
task, but it doesn't stop there. There are for example several spreadsheet programs for
Emacs, there are databases, games, mail and news clients (the top one being Gnus),
etc.</p>
<p>There are two main versions of Emacs: GNU Emacs (which is the version that comes with
Slackware) and XEmacs. The latter is <span class="emphasis"><i
class="EMPHASIS">not</i></span> a version for Emacs running under X. In fact, both Emacs
and XEmacs run on the console as well as under X. XEmacs was once started as a project to
tidy up the Emacs code. Currently, both versions are being actively developed, and there
is in fact much interaction between the two development teams. For the present chapter,
it is immaterial whether you use Emacs or XEmacs, the differences between them are not
relevant to the normal user.</p>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="EMACS-STARTING" name="EMACS-STARTING">17.1 Starting
emacs</a></h2>
<p>Emacs can be started from the shell by simply typing <tt class="COMMAND">emacs</tt>.
When you are running X, Emacs will (normally) come up with its own X window, usually with
a menu bar at the top, where you can find the most important functions. On startup, Emacs
will first show a welcome message, and then after a few seconds will drop you in the
*scratch* buffer. (See <a href="#EMACS-BUFFERS">Section 17.2</a>.)</p>
<div class="INFORMALFIGURE"><a id="AEN5971" name="AEN5971"></a>
<p><img src="emacs/emacs.png" /></p>
</div>
<p>You can also start Emacs on an existing file by typing</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">%</samp> <kbd class="USERINPUT">emacs /etc/resolv.conf</kbd>
</pre>
</td>
</tr>
</table>
<p>This will cause Emacs to load the specified file when it starts up, skipping the
welcome message.</p>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="EMACS-COMMAND-KEYS" name="EMACS-COMMAND-KEYS">17.1.1 Command
Keys</a></h3>
<p>As mentioned above, Emacs uses <b class="KEYCAP">Control</b> and <b
class="KEYCAP">Alt</b> combinations for commands. The usual convention is to write these
with <b class="KEYCAP">C</b>-<b class="KEYCAP">letter</b> and <b class="KEYCAP">M</b>-<b
class="KEYCAP">letter</b>, respectively. So <b class="KEYCAP">C</b>-<b
class="KEYCAP">x</b> means <b class="KEYCAP">Control</b>+<b class="KEYCAP">x</b>, and <b
class="KEYCAP">M</b>-<b class="KEYCAP">x</b> means <b class="KEYCAP">Alt</b>+<b
class="KEYCAP">x</b>. (The letter <b class="KEYCAP">M</b> is used instead of A because
originally the key was not the <b class="KEYCAP">Alt</b> key but the <b
class="KEYCAP">Meta</b> key. The <b class="KEYCAP">Meta</b> key has all but disappeared
from computer keyboards, and in Emacs the <b class="KEYCAP">Alt</b> key has taken over
its function.)</p>
<p>Many Emacs commands consist of sequences of keys and key combinations. For example, <b
class="KEYCAP">C</b>-<b class="KEYCAP">x</b> <b class="KEYCAP">C</b>-<b
class="KEYCAP">c</b> (that is <b class="KEYCAP">Control</b>-<b class="KEYCAP">x</b>
followed by <b class="KEYCAP">Control</b>-<b class="KEYCAP">c</b> ) quits Emacs, <b
class="KEYCAP">C</b>-<b class="KEYCAP">x</b> <b class="KEYCAP">C</b>-<b
class="KEYCAP">s</b> saves the current file. Keep in mind that <b class="KEYCAP">C</b>-<b
class="KEYCAP">x</b> <b class="KEYCAP">C</b>-<b class="KEYCAP">b</b> is <span
class="emphasis"><i class="EMPHASIS">not</i></span> the same as <b
class="KEYCAP">C</b>-<b class="KEYCAP">x</b> <b class="KEYCAP">b</b>. The former means <b
class="KEYCAP">Control</b>-<b class="KEYCAP">x</b> followed by <b
class="KEYCAP">Control</b>-<b class="KEYCAP">b</b>, while the latter means <b
class="KEYCAP">Control</b>-<b class="KEYCAP">x</b> followed by just '<b
class="KEYCAP">b</b>'.</p>
</div>
</div>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="EMACS-BUFFERS" name="EMACS-BUFFERS">17.2 Buffers</a></h2>
<p>In Emacs, the concept of “buffers” is essential. Every file that you open
is loaded into its own buffer. Furthermore, Emacs has several special buffers, which do
not contain a file but are used for other things. Such special buffers usually have a
name that starts and ends with an asterisk. For example, the buffer that Emacs shows when
it is first started, is the so-called *scratch* buffer. In the *scratch* buffer, you can
type text in the normal way, but text that is typed there is not saved when Emacs is
closed.</p>
<p>There is one other special buffer you need to know about, and that is the minibuffer.
This buffer consists of only one line, and is always on the screen: it is the very last
line of the Emacs window, below the status bar for the current buffer. The minibuffer is
where Emacs shows messages for the user, and it is also the place where commands that
require some user input are executed. For example, when you open a file, Emacs will ask
for its name in the minibuffer.</p>
<p>Switching from one buffer to another can be done with the command <b
class="KEYCAP">C</b>-<b class="KEYCAP">x</b> <b class="KEYCAP">b</b>. This will prompt
you for the name of a buffer (a buffer's name is usually the name of the file you are
editing in it), and it gives a default choice, which is normally the buffer that you were
in before you switched to or created the current buffer. Just hitting <span
class="emphasis"><i class="EMPHASIS">Enter</i></span> will switch to that default
buffer.</p>
<p>If you want to switch to another buffer than the default offered by Emacs, just type
its name. Note that you can use so-called <b class="KEYCAP">Tab</b>-completion here: type
the first few letters of the buffer's name and hit <b class="KEYCAP">Tab</b>; Emacs will
then complete the name of the buffer. <b class="KEYCAP">Tab</b> completion works
everywhere in Emacs where it makes sense.</p>
<p>You can get a list of open buffers by hitting <b class="KEYCAP">C</b>-<b
class="KEYCAP">x</b> <b class="KEYCAP">C</b>-<b class="KEYCAP">b</b>. This command will
usually split the screen in two, displaying the buffer you were working in in the top
half, and a new buffer called *Buffer List* in the bottom half. This buffer contains a
list of all the buffers, their sizes and modes, and the files, if any, that those buffers
are visiting (as it is called in Emacs). You can get rid of this split screen by typing
<b class="KEYCAP">C</b>-<b class="KEYCAP">x</b> <b class="KEYCAP">1</b>.</p>
<div class="NOTE">
<table class="NOTE" width="100%" border="0">
<tr>
<td width="25" align="CENTER" valign="TOP"><img src="./imagelib/admon/note.png"
hspace="5" alt="Note" /></td>
<td align="LEFT" valign="TOP">
<p>Under X, the list of buffers is also available in the Buffer menu in the menu bar.</p>
</td>
</tr>
</table>
</div>
</div>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="EMACS-MODES" name="EMACS-MODES">17.3 Modes</a></h2>
<p>Every buffer in Emacs has an associated mode. This mode is very different from the
idea of modes in <tt class="COMMAND">vi</tt>: a mode tells you what kind of buffer you
are in. For example, there is text-mode for normal text files, but there are also modes
such as c-mode for editing C programs, sh-mode for editing shell scripts, latex-mode for
editing <b class="APPLICATION">LaTeX</b> files, mail-mode for editing email and news
messages, etc. A mode provides special customizations and functionality that is useful
for the kind of file you are editing. It is even possible for a mode to redefine keys and
key commands. For example, in Text mode, the Tab key simply jumps to the next tab stop,
but in many programming language modes, the <b class="KEYCAP">Tab</b> key indents the
current line according to the depth of the block that line is in.</p>
<p>The modes mentioned above are called major modes. Each buffer has exactly one major
mode. Additionally, a buffer can have one or more minor modes. A minor mode provides
additional features that may be useful for certain editing tasks. For example, if you hit
the <b class="KEYCAP">INSERT</b> key, you invoke overwrite-mode, which does what you'd
expect. There is also an auto-fill-mode, which is handy in combination with text-mode or
latex-mode: it causes each line that you type to be automatically wrapped once the line
reaches a certain number of characters. Without auto-fill-mode, you have to type <b
class="KEYCAP">M</b>-<b class="KEYCAP">q</b> to fill out a paragraph. (Which you can also
use to reformat a paragraph after you've edited some text in it and it is no longer
nicely filled out.)</p>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="EMACS-OPENING-FILES" name="EMACS-OPENING-FILES">17.3.1 Opening
files</a></h3>
<p>To open a file in Emacs, type</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<kbd class="USERINPUT">C-x C-f</kbd>
</pre>
</td>
</tr>
</table>
<p>Emacs will ask you for the name of the file, filling in some default path for you
(which is usually <tt class="FILENAME">~/</tt> ). After you type the filename (you can
use <b class="KEYCAP">Tab</b> completion) and hit <b class="KEYCAP">ENTER</b> , Emacs
will open the file in a new buffer and display that buffer on the screen.</p>
<div class="NOTE">
<table class="NOTE" width="100%" border="0">
<tr>
<td width="25" align="CENTER" valign="TOP"><img src="./imagelib/admon/note.png"
hspace="5" alt="Note" /></td>
<td align="LEFT" valign="TOP">
<p>Emacs will automatically create a new buffer, it will not load the file into the
current buffer.</p>
</td>
</tr>
</table>
</div>
<p>In order to create a new file in emacs, you cannot just go typing right away. You
first have to create a buffer for it, and come up with a filename. You do this by typing
<b class="KEYCAP">C</b>-<b class="KEYCAP">x</b> <b class="KEYCAP">C</b>-<b
class="KEYCAP">f</b> and typing a filename, just as if you were opening an existing file.
Emacs will notice that the file you typed doesn't exist, and will create a new buffer and
report “(New file)” in the minibuffer.</p>
<p>When you type <b class="KEYCAP">C</b>-<b class="KEYCAP">x</b> <b
class="KEYCAP">C</b>-<b class="KEYCAP">f</b> and then enter a directory name instead of a
filename, Emacs will create a new buffer in which you will find a list of all the files
in that directory. You can move the cursor to the file that you are looking for and type
, and Emacs will open it. (There are in fact a lot more actions you can perform here,
such as deleting, renaming and moving files, etc. Emacs is now in dired-mode, which is
basically a simple file manager.)</p>
<p>When you have typed <b class="KEYCAP">C</b>-<b class="KEYCAP">x</b> <b
class="KEYCAP">C</b>-<b class="KEYCAP">f</b> and suddenly change your mind, you can type
<b class="KEYCAP">C</b>-<b class="KEYCAP">g</b> to cancel the action. <b
class="KEYCAP">C</b>-<b class="KEYCAP">g</b> works almost everywhere where you want to
cancel an action or command that you've started but don't want to finish.</p>
</div>
</div>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="EMACS-BASIC-EDITING" name="EMACS-BASIC-EDITING">17.4 Basic
Editing</a></h2>
<p>When you have opened a file, you can of course move around in it with the cursor. The
<b class="KEYCAP">cursor keys</b> and <b class="KEYCAP">PgUp</b>, <b
class="KEYCAP">PgDn</b> do what you'd expect. <b class="KEYCAP">Home</b> and <b
class="KEYCAP">End</b> jump to the beginning and end of the line. (In older versions,
they would actually jump to the beginning and end of the buffer.) However, there are also
<b class="KEYCAP">Control</b> and <b class="KEYCAP">Meta</b> (<b class="KEYCAP">Alt</b>)
key combos that move the cursor around. Because you do not need to move your hands to
another part of the keyboard for these, they are much quicker once you get used to them.
The most important such commands are listed in <a href="#TABLE-EMACS-BASIC-EDITING">Table
17-1</a>.</p>
<div class="TABLE"><a id="TABLE-EMACS-BASIC-EDITING"
name="TABLE-EMACS-BASIC-EDITING"></a>
<p><b>Table 17-1. Basic Emacs Editing Commands</b></p>
<table border="0" frame="void" width="100%" class="CALSTABLE">
<col width="25%" />
<col width="75%" />
<thead>
<tr>
<th>Command</th>
<th>Result</th>
</tr>
</thead>
<tbody>
<tr>
<td><b class="KEYCAP">C</b>-<b class="KEYCAP">b</b> </td>
<td>go one character back</td>
</tr>
<tr>
<td><b class="KEYCAP">C</b>-<b class="KEYCAP">f</b> </td>
<td>go one character forward</td>
</tr>
<tr>
<td><b class="KEYCAP">C</b>-<b class="KEYCAP">n</b> </td>
<td>go one line down</td>
</tr>
<tr>
<td><b class="KEYCAP">C</b>-<b class="KEYCAP">p</b> </td>
<td>go one line up</td>
</tr>
<tr>
<td><b class="KEYCAP">C</b>-<b class="KEYCAP">a</b> </td>
<td>go to the beginning of the line</td>
</tr>
<tr>
<td><b class="KEYCAP">C</b>-<b class="KEYCAP">e</b> </td>
<td>go to the end of the line</td>
</tr>
<tr>
<td><b class="KEYCAP">M</b>-<b class="KEYCAP">b</b> </td>
<td>go one word back</td>
</tr>
<tr>
<td><b class="KEYCAP">M</b>-<b class="KEYCAP">f</b> </td>
<td>go one word forward</td>
</tr>
<tr>
<td><b class="KEYCAP">M</b>-<b class="KEYCAP">}</b> </td>
<td>go one paragraph forward</td>
</tr>
<tr>
<td><b class="KEYCAP">M</b>-<b class="KEYCAP">{</b> </td>
<td>go one paragraph backward</td>
</tr>
<tr>
<td><b class="KEYCAP">M</b>-<b class="KEYCAP">a</b> </td>
<td>go one sentence backward</td>
</tr>
<tr>
<td><b class="KEYCAP">M</b>-<b class="KEYCAP">e</b> </td>
<td>go one sentence forward</td>
</tr>
<tr>
<td><b class="KEYCAP">C</b>-<b class="KEYCAP">d</b> </td>
<td>delete the character under the cursor</td>
</tr>
<tr>
<td><b class="KEYCAP">M</b>-<b class="KEYCAP">d</b> </td>
<td>delete until the end of the current word</td>
</tr>
<tr>
<td><b class="KEYCAP">C</b>-<b class="KEYCAP">v</b> </td>
<td>go down one screen (i.e., PgDn)</td>
</tr>
<tr>
<td><b class="KEYCAP">M</b>-<b class="KEYCAP">v</b> </td>
<td>go up one screen (i.e., PgUp)</td>
</tr>
<tr>
<td><b class="KEYCAP">M</b>-<b class="KEYCAP"><</b> </td>
<td>go to the beginning of the buffer</td>
</tr>
<tr>
<td><b class="KEYCAP">M</b>-<b class="KEYCAP">></b> </td>
<td>go to the end of the buffer</td>
</tr>
<tr>
<td><b class="KEYCAP">C</b>-<b class="KEYCAP">_</b> </td>
<td>undo the last change (can be repeated); note that you actually have to type <b
class="KEYCAP">Shift</b>+<b class="KEYCAP">Control</b>+<b class="KEYCAP">hyphen</b> for
this.</td>
</tr>
<tr>
<td><b class="KEYCAP">C</b>-<b class="KEYCAP">k</b> </td>
<td>delete to end of line</td>
</tr>
<tr>
<td><b class="KEYCAP">C</b>-<b class="KEYCAP">s</b> </td>
<td>forward search</td>
</tr>
<tr>
<td><b class="KEYCAP">C</b>-<b class="KEYCAP">r</b> </td>
<td>backward search</td>
</tr>
</tbody>
</table>
</div>
<p>Note that many <b class="KEYCAP">Meta</b> commands are parallel to the <b
class="KEYCAP">Control</b> commands except that they operate on larger units: while <b
class="KEYCAP">C</b>-<b class="KEYCAP">f</b> goes forward one character, <b
class="KEYCAP">M</b>-<b class="KEYCAP">f</b> goes forward an entire word, etc.</p>
<p>Also note that <b class="KEYCAP">M</b>-<b class="KEYCAP"><</b> and <b
class="KEYCAP">M</b>-<b class="KEYCAP">></b> require you to type <b
class="KEYCAP">Shift</b>+<b class="KEYCAP">Alt</b>+<b class="KEYCAP">comma</b> and <b
class="KEYCAP">Shift</b>+<b class="KEYCAP">Alt</b>+<b class="KEYCAP">dot</b>
respectively, since <b class="KEYCAP"><</b> and <b class="KEYCAP">></b> are on <b
class="KEYCAP">Shift</b>+<b class="KEYCAP">comma</b> and <b class="KEYCAP">Shift</b>+<b
class="KEYCAP">dot</b>. (Unless of course you have a different keyboard layout from the
standard US layout.)</p>
<p>Note that <b class="KEYCAP">C</b>-<b class="KEYCAP">k</b> deletes (kills, as it is
commonly called) all the text after the cursor to the end of the line, but doesn't delete
the line itself (i.e., it doesn't delete the final newline). It only deletes the line if
there was no text after the cursor. In other words, in order to delete a complete line,
you have to put the cursor at the beginning of the line, and then hit <b
class="KEYCAP">C</b>-<b class="KEYCAP">k</b> twice: once to delete the text on the line,
once to delete the line itself.</p>
</div>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="EMACS-SAVING-FILES" name="EMACS-SAVING-FILES">17.5 Saving
Files</a></h2>
<p>In order to save a file, you type</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<kbd class="USERINPUT">C-x C-s</kbd>
</pre>
</td>
</tr>
</table>
<p>Emacs will not ask you for a filename, the buffer will just be saved to the file it
was loaded from. If you want to save your text to another file, type</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<kbd class="USERINPUT">C-x C-w</kbd>
</pre>
</td>
</tr>
</table>
<p>When you save the file for the first time in this session, Emacs will normally save
the old version of your file to a backup file, which has the same name appended with a
tilde: so if you're editing a file “<tt class="FILENAME">cars.txt</tt>”,
Emacs will create a backup “<tt class="FILENAME">cars.txt~</tt>”.</p>
<p>This backup file is a copy of the file that you opened. While you are working, Emacs
will also regularly create an auto-save copy of the work you are doing, to a file named
with hash signs: <tt class="FILENAME">#cars.txt#</tt>. This backup is deleted when you
save the file with C-x C-s.</p>
<p>When you are done editing a file, you can kill the buffer that holds it by typing</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<kbd class="USERINPUT">C-x k</kbd>
</pre>
</td>
</tr>
</table>
<p>Emacs will then ask you which buffer you want to kill, with the current buffer as
default, which you can select by hitting <b class="KEYCAP">ENTER</b>. If you haven't
saved your file yet, Emacs will ask you if you really want to kill the buffer.</p>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="EMACS-QUITING" name="EMACS-QUITING">17.5.1 Quitting
Emacs</a></h3>
<p>When you are done with Emacs altogether, you can type</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<kbd class="USERINPUT">C-x C-c</kbd>
</pre>
</td>
</tr>
</table>
<p>This quits Emacs. If you have any unsaved files, Emacs will tell you so, and ask if
you want to save them each in turn. If you answer no to any of these, Emacs will ask for
one final confirmation and then quit.</p>
</div>
</div>
</div>
<div class="CHAPTER">
<hr />
<h1><a id="PACKAGE-MANAGEMENT" name="PACKAGE-MANAGEMENT"></a>Chapter 18 Slackware Package
Management</h1>
<p>A software package is a bundle of related programs that are ready for you to install.
When you download a source code archive, you have to configure, compile, and install it
by hand. With a software package, this has already been done for you. All that you have
to do is install the package. Another handy feature of using software packages is that it
is very easy to remove and upgrade them, if you so desire. Slackware comes with programs
for all your package management needs. You can install, remove, upgrade, make, and
examine packages very easily.</p>
<p>There's a myth that's been going around ever since RedHat debuted RedHat Package
Manager, that Slackware has no package management tool. This simply couldn't be further
from the truth. Slackware has always included a package manager, even before RedHat
existed. While not as full-featured or as ubiquitous as rpm (or for that matter deb), <tt
class="COMMAND">pkgtool</tt> and its associated programs are every bit as good at
installing packages as rpm. The truth about <tt class="COMMAND">pkgtool</tt> is not that
it doesn't exist, but that it doesn't do any dependency checking.</p>
<p>Apparently many people in the Linux community think that a packager manager must by
definition include dependency checking. Well, that simply isn't the case, as Slackware
most certainly does not. This is not to say that Slackware packages don't have
dependencies, but rather that its package manager doesn't check for them. Dependency
management is left up to the sysadmin, and that's the way we like it.</p>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="PACKAGE-MANAGEMENT-OVERVIEW"
name="PACKAGE-MANAGEMENT-OVERVIEW">18.1 Overview of Package Format</a></h2>
<p>Before learning the utilities, you should become familiar with the format of a
Slackware package. In Slackware, a package is simply a tar archive file that has been
compressed with <tt class="COMMAND">gzip</tt>. Packages are built to be extracted in the
root directory.</p>
<p>Here is a fictitious program and its example package:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
./
usr/
usr/bin/
usr/bin/makehejaz
usr/doc/
usr/doc/makehejaz-1.0/
usr/doc/makehejaz-1.0/COPYING
usr/doc/makehejaz-1.0/README
usr/man/
usr/man/man1
usr/man/man1/makehejaz.1.gz
install/
install/doinst.sh
</pre>
</td>
</tr>
</table>
<p>The package system will extract this file in the root directory to install it. An
entry in the package database will be created that contains the contents of this package
so that it can be upgraded or removed later.</p>
<p>Notice the <tt class="FILENAME">install/</tt> subdirectory. This is a special
directory that can contain a postinstallation script called <tt
class="FILENAME">doinst.sh</tt>. If the package system finds this file, it will execute
it after installing the package.</p>
<p>Other scripts can be embedded in the package, but those are discussed more in detail
in <a href="#PACKAGE-MANAGEMENT-MAKEPKG">Section 18.3.2</a> below.</p>
</div>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="PACKAGE-MANAGEMENT-PACKAGE-UTILITIES"
name="PACKAGE-MANAGEMENT-PACKAGE-UTILITIES">18.2 Package Utilities</a></h2>
<p>There are four main utilities for package management. They perform installation,
removal, and upgrades of packages.</p>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="PACKAGE-MANAGEMENT-PACKAGE-UTILITIES-PKGTOOL"
name="PACKAGE-MANAGEMENT-PACKAGE-UTILITIES-PKGTOOL">18.2.1 pkgtool</a></h3>
<p><tt class="COMMAND">pkgtool</tt>(8) is a menu-driven program that allows installation
and removal of packages. The main menu is shown in <a href="#PKGTOOL-MAIN-MENU">Figure
18-1</a>.</p>
<div class="FIGURE"><a id="PKGTOOL-MAIN-MENU" name="PKGTOOL-MAIN-MENU"></a>
<p><b>Figure 18-1. Pkgtool's main menu.</b></p>
<p><img src="package-management/pkgtool-w.png" /></p>
</div>
<p>Installation is offered from the current directory, another directory, or from floppy
disks. Simply select the installation method you want and pkgtool will search that
location for valid packages to install.</p>
<p>You may also view a list of installed packages, as shown in <a
href="#PKGTOOL-VIEW-MODE">Figure 18-2</a>.</p>
<div class="FIGURE"><a id="PKGTOOL-VIEW-MODE" name="PKGTOOL-VIEW-MODE"></a>
<p><b>Figure 18-2. Pkgtool view mode</b></p>
<p><img src="package-management/pkgtool-view-w.png" /></p>
</div>
<p>If you want to remove packages, select the remove option and you will be presented
with a checklist of all the installed packages. Flag the ones you want to remove and
select OK. <tt class="COMMAND">pkgtool</tt> will remove them.</p>
<p>Some users prefer this utility to the command line utilities. However, it should be
noted that the command line utilities offer many more options. Also, the ability to
upgrade packages is only offered through the command line utilities.</p>
</div>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="PACKAGE-MANAGEMENT-PACKAGE-UTILITIES-INSTALLPKG"
name="PACKAGE-MANAGEMENT-PACKAGE-UTILITIES-INSTALLPKG">18.2.2 installpkg</a></h3>
<p><tt class="COMMAND">installpkg</tt>(8) handles installation of new packages on the
system. The syntax is as follows:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">#</samp> <kbd class="USERINPUT">installpkg option package_name</kbd>
</pre>
</td>
</tr>
</table>
<p>Three options are provided for <tt class="COMMAND">installpkg</tt>. Only one option
can be used at a time.</p>
<div class="TABLE"><a id="AEN6446" name="AEN6446"></a>
<p><b>Table 18-1. <tt class="COMMAND">installpkg</tt> Options</b></p>
<table border="0" frame="void" class="CALSTABLE">
<col width="1*" />
<col width="3*" />
<thead>
<tr>
<th align="LEFT">Option</th>
<th align="LEFT">Effects</th>
</tr>
</thead>
<tbody>
<tr>
<td>-m</td>
<td>Performs a makepkg operation on the current directory.</td>
</tr>
<tr>
<td>-warn</td>
<td>Shows what would happen if you installed the specified package. This is useful for
production systems so you can see exactly what would happen before installing
something.</td>
</tr>
<tr>
<td>-r</td>
<td>Recursively install all packages in the current directory and down. The package name
can use wildcards, which would be used as the search mask when recursively
installing.</td>
</tr>
</tbody>
</table>
</div>
<p>If you pass the <tt class="ENVAR">ROOT</tt> environment variable before <tt
class="COMMAND">installpkg</tt>, that path will be used for the root directory. This is
useful for setting up new drives for your root directory. They will typically be mounted
to <tt class="FILENAME">/mnt</tt> or something other than <tt
class="FILENAME">/</tt>.</p>
<p>The installed package database entry is stored in <tt
class="FILENAME">/var/log/packages</tt>. The entry is really just a plain text file, one
for each package. If the package has a postinstallation script, it is written to <tt
class="FILENAME">/var/log/scripts/</tt>.</p>
<p>You may specify several packages or use wildcards for the package name. Be advised
that <tt class="COMMAND">installpkg</tt> will not tell you if you are overwriting an
installed package. It will simply install right on top of the old one. If you want to
ensure that old files from the previous package are safely removed, use <tt
class="COMMAND">upgradepkg</tt>.</p>
</div>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="PACKAGE-MANAGEMENT-PACKAGE-UTILITIES-REMOVEPKG"
name="PACKAGE-MANAGEMENT-PACKAGE-UTILITIES-REMOVEPKG">18.2.3 removepkg</a></h3>
<p><tt class="COMMAND">removepkg</tt>(8) handles removing installed packages from the
system. The syntax is as follows:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">#</samp> <kbd class="USERINPUT">removepkg option package_name</kbd>
</pre>
</td>
</tr>
</table>
<p>Four options are provided for <tt class="COMMAND">removepkg</tt>. Only one option may
be used at a time.</p>
<div class="TABLE"><a id="AEN6491" name="AEN6491"></a>
<p><b>Table 18-2. <tt class="COMMAND">removepkg</tt> Options</b></p>
<table border="0" frame="void" class="CALSTABLE">
<col width="1*" />
<col width="3*" />
<thead>
<tr>
<th>Option</th>
<th>Effects</th>
</tr>
</thead>
<tbody>
<tr>
<td>-copy</td>
<td>The package is copied to the preserved packages directory. This creates a tree of the
original package without removing it.</td>
</tr>
<tr>
<td>-keep</td>
<td>Saves temporary files created during the removal. Really only useful for debugging
purposes.</td>
</tr>
<tr>
<td>-preserve</td>
<td>The package is removed, but copied to the preserved packages directory at the same
time.</td>
</tr>
<tr>
<td>-warn</td>
<td>Shows what would happen if you removed the package.</td>
</tr>
</tbody>
</table>
</div>
<p>If you pass the <tt class="ENVAR">ROOT</tt> environment variable before <tt
class="COMMAND">removepkg</tt>, that path will be used for the root directory. This is
useful for setting up new drives for your root directory. They will typically be mounted
to <tt class="FILENAME">/mnt</tt> or something other than <tt
class="FILENAME">/</tt>.</p>
<p><tt class="COMMAND">removepkg</tt> looks at the other installed packages and only
removes files unique to the package you specify. It will also scan the postinstallation
script for the specified package and remove any symbolic links that were created by
it.</p>
<p>During the removal process, a status report is displayed. After the removal, the
package database entry is moved to <tt class="FILENAME">/var/log/removed_packages</tt>
and the postinstallation script is moved to <tt
class="FILENAME">/var/log/removed</tt>_scripts.</p>
<p>Just as with <tt class="COMMAND">installpkg</tt>, you can specify several packages or
use wildcards for the package name.</p>
</div>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="PACKAGE-MANAGEMENT-PACKAGE-UTILITIES-UPGRADEPKG"
name="PACKAGE-MANAGEMENT-PACKAGE-UTILITIES-UPGRADEPKG">18.2.4 upgradepkg</a></h3>
<p><tt class="COMMAND">upgradepkg</tt>(8) will upgrade an installed Slackware package.
The syntax is as follows:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">#</samp> <kbd class="USERINPUT">upgradepkg package_name</kbd>
</pre>
</td>
</tr>
</table>
<p>or</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
<samp class="PROMPT">#</samp> <kbd
class="USERINPUT">upgradepkg old_package_name%new_package_name</kbd>
</pre>
</td>
</tr>
</table>
<p><tt class="COMMAND">upgradepkg</tt> works by first installing the new package and then
removing the old package so that old files are no longer around on the system. If the
upgraded package name has changed, use the percent sign syntax to specify the old package
(the one that is installed) and the new package (the one you are upgrading it to).</p>
<p>If you pass the <tt class="ENVAR">ROOT</tt> environment variable before <tt
class="COMMAND">upgradepkg</tt>, that path will be used for the root directory. This is
useful for setting up new drives for your root directory. They will typically be mounted
to <tt class="FILENAME">/mnt</tt> or something other than <tt
class="FILENAME">/</tt>.</p>
<p><tt class="COMMAND">upgradepkg</tt> is not flawless. You should always back up your
configuration files. If they get removed or overwritten, you'll want a copy of the
originals for any needed repair work.</p>
<p>Just as with <tt class="COMMAND">installpkg</tt> and <tt
class="COMMAND">removepkg</tt>, you can specify several packages or use wildcards for the
package name.</p>
</div>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="PACKAGE-MANAGEMENT-PACKAGE-UTILITIES-RPM"
name="PACKAGE-MANAGEMENT-PACKAGE-UTILITIES-RPM">18.2.5 <tt
class="COMMAND">rpm2tgz</tt>/<tt class="COMMAND">rpm2targz</tt></a></h3>
<p>The Red Hat Package Manager is a popular packaging system available today. Many
software distributors are offering their products in RPM format. Since this is not our
native format, we do not recommend people rely on them. However, some things are only
available as an RPM (even the source).</p>
<p>We provide a program that will convert RPM packages to our native <tt
class="FILENAME">.tgz</tt> format. This will allow you to extract the package (perhaps
with <tt class="COMMAND">explodepkg</tt>) to a temporary directory and examine its
contents.</p>
<p>The <tt class="COMMAND">rpm2tgz</tt> program will create a Slackware package with a
<tt class="FILENAME">.tgz</tt> extension, while <tt class="FILENAME">rpm2targz</tt>
creates an archive with a <tt class="FILENAME">.tar.gz</tt> extension.</p>
</div>
</div>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="PACKAGE-MANAGEMENT-MAKING-PACKAGES"
name="PACKAGE-MANAGEMENT-MAKING-PACKAGES">18.3 Making Packages</a></h2>
<p>Making Slackware packages can be either easy or difficult. There is no specific method
for building a package. The only requirement is that the package be a tar gzipped file
and if there is a postinstallation script, it must be <tt
class="FILENAME">/install/doinst.sh</tt>.</p>
<p>If you are interested in making packages for your system or for a network that you
manage, you should have a look at the various build scripts in the Slackware source tree.
There are several methods we use for making packages.</p>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="PACKAGE-MANAGEMENT-EXPLODEPKG"
name="PACKAGE-MANAGEMENT-EXPLODEPKG">18.3.1 <tt class="COMMAND">explodepkg</tt></a></h3>
<p><tt class="COMMAND">explodepkg</tt>(8) will do the same thing that <tt
class="COMMAND">installpkg</tt> does to extract the package, but it doesn't actually
install it and it doesn't record it in the packages database. It simply extracts it to
the current directory.</p>
<p>If you look at the Slackware source tree, you will see how we use this command for
“framework” packages. These packages contain a skeleton of what the final
package will look like. They hold all the necessary filenames (zero-length), permissions,
and ownerships. The build script will cat the package contents from the source directory
to the package build directory.</p>
</div>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="PACKAGE-MANAGEMENT-MAKEPKG"
name="PACKAGE-MANAGEMENT-MAKEPKG">18.3.2 <tt class="COMMAND">makepkg</tt></a></h3>
<p><tt class="COMMAND">makepkg</tt>(8) will package up the current directory into a valid
Slackware package. It will search the tree for any symbolic links and add a creation
block to the postinstallation script for creating them during the package install. It
also warns of any zero-length files in the package tree.</p>
<p>This command is typically run after you have created your package tree.</p>
</div>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="PACKAGE-MANAGEMENT-SLACKBUILD-SCRIPTS"
name="PACKAGE-MANAGEMENT-SLACKBUILD-SCRIPTS">18.3.3 SlackBuild Scripts</a></h3>
<p>Slackware packages are built in many different ways by necessity. Not all software
packages are written by their programmers to compile the same way. Many have compile time
options that are not all included in the packages Slackware uses. Perhaps you need some
of this functionality; you'll need to compile your own package then. Fortunately for many
Slackware packages, you can find SlackBuild scripts in the package's source code.</p>
<p>So what is a SlackBuild script? SlackBuild scripts are executable shell scripts that
you run as <tt class="USERNAME">root</tt> to configure, compile, and create Slackware
packages. You can freely modify these scripts in the source directory and run them to
create your own versions of the default Slackware packages.</p>
</div>
</div>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="PACKAGE-MANAGEMENT-MAKING-TAGS-AND-TAGFILES"
name="PACKAGE-MANAGEMENT-MAKING-TAGS-AND-TAGFILES">18.4 Making Tags and Tagfiles (for
setup)</a></h2>
<p>The Slackware setup program handles installation of the software packages on your
system. There are files that tell the setup program which packages must be installed,
which ones are optional, and which ones are selected by default by the setup program.</p>
<p>A tagfile is in the first software series directory and is called tagfile. It lists
the packages in that particular disk set and their status. The status can be:</p>
<div class="TABLE"><a id="AEN6621" name="AEN6621"></a>
<p><b>Table 18-3. Tagfile Status Options</b></p>
<table border="0" frame="void" width="100%" class="CALSTABLE">
<col width="25%" />
<col width="75%" />
<thead>
<tr>
<th>Option</th>
<th>Meaning</th>
</tr>
</thead>
<tbody>
<tr>
<td>ADD</td>
<td>The package is required for proper system operation</td>
</tr>
<tr>
<td>SKP</td>
<td>The package will be automatically skipped</td>
</tr>
<tr>
<td>REC</td>
<td>The package is not required, but recommended</td>
</tr>
<tr>
<td>OPT</td>
<td>The package is optional</td>
</tr>
</tbody>
</table>
</div>
<p>The format is simply:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
package_name: status
</pre>
</td>
</tr>
</table>
<p>One package per line. The original tagfiles for each software series are stored as
tagfile.org. So if you mess up yours, you can restore the original one.</p>
<p>Many administrators prefer writing their own tagfiles and starting the installer and
selecting “full”. The setup program will read the tagfiles and perform the
installation according to their contents. If you use REC or OPT, a dialog box will be
presented to the user asking whether or not they want a particular package. Therefore, it
is recommended that you stick with ADD and SKP when writing tagfiles for automated
installs.</p>
<p>Just make sure your tagfiles are written to the same location as the originals. Or you
can specify a custom tagfile path if you have custom tagfiles.</p>
</div>
</div>
<div class="CHAPTER">
<hr />
<h1><a id="ZIPSLACK" name="ZIPSLACK"></a>Chapter 19 ZipSlack</h1>
<div class="SECT1">
<h2 class="SECT1"><a id="ZIPSLACK-WHAT" name="ZIPSLACK-WHAT">19.1 What is
ZipSlack?</a></h2>
<p>ZipSlack is a special version of Slackware Linux. It's an already installed copy of
Slackware that's ready to run from your DOS or Windows partition. It's a basic
installation, you do not get everything that comes with Slackware.</p>
<p>ZipSlack gets its name from the form it's distributed in, a big .ZIP file. Users of
DOS and Windows will probably be familiar with these files. They are compressed archives.
The ZipSlack archive contains everything you need to get up and running with
Slackware.</p>
<p>It is important to note that ZipSlack is significantly different from a regular
installation. Even though they function the same and contain the same programs, their
intended audiences and functions differ. Several advantages and disadvantages of ZipSlack
are discussed below.</p>
<p>One last thing, you should always review the documentation included in the actual
ZipSlack directory. It contains the latest information regarding installation, booting,
and general use of the product.</p>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="ZIPSLACK-ADVANTAGES" name="ZIPSLACK-ADVANTAGES">19.1.1
Advantages</a></h3>
<ul>
<li>
<p>Does not require repartitioning of your hard disk.</p>
</li>
<li>
<p>Great way to learn Slackware Linux without stumbling through the installation
process.</p>
</li>
</ul>
</div>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="ZIPSLACK-DISADVANTAGES" name="ZIPSLACK-DISADVANTAGES">19.1.2
Disadvantages</a></h3>
<ul>
<li>
<p>Uses the DOS filesystem, which is slower than a native Linux filesystem.</p>
</li>
<li>
<p>Will not work with Windows NT.</p>
</li>
</ul>
</div>
</div>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="ZIPSLACK-GETTING" name="ZIPSLACK-GETTING">19.2 Getting
ZipSlack</a></h2>
<p>Obtaining ZipSlack is easy. If you have purchased the official Slackware Linux CD set,
then you already have ZipSlack. Just find the CD that contains the <tt
class="FILENAME">zipslack</tt> directory and place it in your CD-ROM drive. It's usually
the third or fourth disc, but always trust the labels over this documentation as the disk
it resides on is prone to change.</p>
<p>If you want to download ZipSlack, you should first visit our “Get Slack”
web page for the latest download information:</p>
<p><a href="http://www.slackware.com/getslack/"
target="_top">http://www.slackware.com/getslack/</a></p>
<p>ZipSlack is part of each Slackware release. Locate the release you want, and go to
that directory on the FTP site. The latest release directory can be found at this
location:</p>
<p><a href="ftp://ftp.slackware.com/pub/slackware/slackware/"
target="_top">ftp://ftp.slackware.com/pub/slackware/slackware/</a></p>
<p>You'll find ZipSlack in the <tt class="FILENAME">/zipslack</tt> subdirectory. ZipSlack
is offered as one big <tt class="FILENAME">.ZIP</tt> file or floppy-sized chunks. The
chunks are in the <tt class="FILENAME">/zipslack/split</tt> directory.</p>
<p>Don't stop at just the <tt class="FILENAME">.ZIP</tt> files. You should also download
the documentation files and any boot images that appear in the directory.</p>
<div class="SECT2">
<hr />
<h3 class="SECT2"><a id="ZIPSLACK-INSTALLATION" name="ZIPSLACK-INSTALLATION">19.2.1
Installation</a></h3>
<p>Once you've downloaded the necessary components, you'll need to extract the <tt
class="FILENAME">.ZIP</tt> file. Be sure to use a 32-bit unzipper. The size and filenames
in the archive are too much for a 16-bit unzipper. Examples of 32-bit unzippers include
WinZip and PKZIP for Windows.</p>
<p>ZipSlack is designed to be extracted directly to the root directory of a drive (such
as <tt class="DEVICENAME">C:</tt> or <tt class="DEVICENAME">D:</tt>). A <tt
class="FILENAME">\LINUX</tt> directory will be created that contains the actual Slackware
installation. You'll also find the files necessary to booting the system in that
directory as well.</p>
<p>After you've extracted the files, you should have a <tt class="FILENAME">\LINUX</tt>
directory on the drive of your choosing (we'll use <tt class="DEVICENAME">C:</tt> from
here on).</p>
</div>
</div>
<div class="SECT1">
<hr />
<h2 class="SECT1"><a id="ZIPSLACK-BOOTING" name="ZIPSLACK-BOOTING">19.3 Booting
ZipSlack</a></h2>
<p>There are several ways to boot ZipSlack. The most common is to use the included
LINUX.BAT to boot the system from DOS (or from DOS mode under Windows 9x). This file must
be edited to match your system before it will work.</p>
<p>Start by opening the <tt class="FILENAME">C:\LINUX\LINUX.BAT</tt> file in your
favorite text editor. At the top of the file you will notice a large comment. It explains
what you need to edit in this file (and also what to do if you are booting from an
external Zip drive). Don't worry if you don't understand the <var
class="LITERAL">root=</var> setting. There are several examples, so feel free to pick one
and try it. If it doesn't work, you can edit the file again, comment out the line you
uncommented, and pick another one.</p>
<p>After you uncomment the line you want by removing the “rem” at the
beginning of the line, save the file and exit the editor. Bring your machine into DOS
mode.</p>
<p>A DOS prompt window in Windows 9x will NOT work.</p>
<p>Type <tt class="COMMAND">C:\LINUX\LINUX.BAT</tt> to boot the system. If all goes well,
you should be presented with a login prompt.</p>
<p>Log in as <tt class="USERNAME">root</tt>, with no password. You'll probably want to
set a password for root, as well as adding an account for yourself. At this point you can
refer to the other sections in this book for general system usage.</p>
<p>If using the <tt class="FILENAME">LINUX.BAT</tt> file to boot the system didn't work
for you, you should refer to the included <tt class="FILENAME">C:\LINUX\README.1ST</tt>
file for other ways to boot.</p>
</div>
</div>
<div class="GLOSSARY">
<h1><a id="GLOSSARY" name="GLOSSARY"></a>Glossary</h1>
<dl>
<dt><b>Account</b></dt>
<dd>
<p>All of the information about a user, including username, password, finger information,
UID and GID, and home directory. To create an account is to add and define a user.</p>
</dd>
<dt><b>Background</b></dt>
<dd>
<p>Any process that is running without accepting or controlling the input of a terminal
is said to be running in the background.</p>
</dd>
<dt><b>Boot disk</b></dt>
<dd>
<p>A floppy disk containing an operating system (in our case, the Linux kernel) from
which a computer can be started.</p>
</dd>
<dt><b>Compile</b></dt>
<dd>
<p>To convert source code to machine-readable “binary” code.</p>
</dd>
<dt><b>Daemon</b></dt>
<dd>
<p>A program designed to run in the background and, without user intervention, perform a
specific task (usually providing a service).</p>
</dd>
<dt><b>Darkstar</b></dt>
<dd>
<p>The default hostname in Slackware; your computer will be called darkstar if you do not
specify some other name.</p>
<p>One of Patrick Volkerding's development machines, named after “Dark Star”,
a song by the Grateful Dead.</p>
</dd>
<dt><b>Desktop Environment</b></dt>
<dd>
<p>A graphical user interface (GUI) that runs atop the X Window System and provides such
features as integrated applications, cohesive look-and-feel between programs and
components, file and window management capabilities, etc. A step beyond the simple window
manager.</p>
</dd>
<dt><b>Device driver</b></dt>
<dd>
<p>A chunk of code in the kernel that directly controls a piece of hardware.</p>
</dd>
<dt><b>Device node</b></dt>
<dd>
<p>A special type of file in the <tt class="FILENAME">/dev</tt> filesystem that
represents a hardware component to the operating system.</p>
</dd>
<dt><b>DNS</b></dt>
<dd>
<p>Domain Name Service. A system in which networked computers are given names which
translate to numerical addresses.</p>
</dd>
<dt><b>Domain name</b></dt>
<dd>
<p>A computer's DNS name, excluding its host name.</p>
</dd>
<dt><b>Dot file</b></dt>
<dd>
<p>In Linux, files which are to be hidden have filenames beginning with a dot ('.').</p>
</dd>
<dt><b>Dotted quad</b></dt>
<dd>
<p>The format of IP addresses, so called because it consists of four numbers (range 0-255
decimal) separated by periods.</p>
</dd>
<dt><b>Dynamic loader</b></dt>
<dd>
<p>When programs are compiled under Linux, they usually use pieces of code (functions)
from external libraries. When such programs are run, those libraries must be found and
the required functions loaded into memory. This is the job of the dynamic loader.</p>
</dd>
<dt><b>Environment variable</b></dt>
<dd>
<p>A variable set in the user's shell which can be referenced by that user or programs
run by that user within that shell. Environment variables are generally used to store
preferences and default parameters.</p>
</dd>
<dt><b>Epoch</b></dt>
<dd>
<p>A period of history; in Unix, “The Epoch” begins at 00:00:00 UTC January
1, 1970. This is considered the “dawn of time” by Unix and Unix-like
operating systems, and all other time is calculated relative to this date.</p>
</dd>
<dt><b>Filesystem</b></dt>
<dd>
<p>A representation of stored data in which “files” of data are kept
organized in “directories”. The filesystem is the nearly universal form of
representation for data stored to disks (both fixed and removable).</p>
</dd>
<dt><b>Foreground</b></dt>
<dd>
<p>A program that is accepting or controlling a terminal's input is said to be running in
the foreground.</p>
</dd>
<dt><b>Framebuffer</b></dt>
<dd>
<p>A type of graphics device; in Linux, this most often refers to the software
framebuffer, which provides a standard framebuffer interface to programs while keeping
specific hardware drivers hidden from them. This layer of abstraction frees programs of
the need to speak to various hardware drivers.</p>
</dd>
<dt><b>FTP</b></dt>
<dd>
<p>The File Transfer Protocol. FTP is a very popular method of transferring data between
computers.</p>
</dd>
<dt><b>Gateway</b></dt>
<dd>
<p>A computer through which data on a network is transferred to another network.</p>
</dd>
<dt><b>GID</b></dt>
<dd>
<p>Group Identifier. The GID is a unique number attributed to a group of users.</p>
</dd>
<dt><b>Group</b></dt>
<dd>
<p>Users in Unix belong to “groups”, which can contain many other users and
are used for more general access control than the existence of users alone can easily
allow.</p>
</dd>
<dt><b>GUI</b></dt>
<dd>
<p>Graphical User Interface. A software interface that uses rendered graphical elements
such as buttons, scrollbars, windows, etc. rather than solely text-based input and
output</p>
</dd>
<dt><b>Home directory</b></dt>
<dd>
<p>A user's “home directory” is the directory the user is placed in
immediately upon logging in. Users have full permissions and more or less free reign
within their home directories.</p>
</dd>
<dt><b>HOWTO</b></dt>
<dd>
<p>A document describing “how to” do something, such as configure a firewall
or manage users and groups. There is a large collection of these documents available from
the Linux Documentation Project.</p>
</dd>
<dt><b>HTTP</b></dt>
<dd>
<p>The Hypertext Transfer Protocol. HTTP is the primary protocol on which the World Wide
Web operates.</p>
</dd>
<dt><b>ICMP</b></dt>
<dd>
<p>Internet Control Message Protocol. A very basic networking protocol, used mostly for
pings.</p>
</dd>
<dt><b>Kernel</b></dt>
<dd>
<p>The heart of an operating system. The kernel is the part that provides basic process
control and interfaces with the computer's hardware.</p>
</dd>
<dt><b>Kernel module</b></dt>
<dd>
<p>A piece of kernel code, usually a driver of some sort, that can be loaded and unloaded
from memory separately from the main body of the kernel. Modules are handy when upgrading
drivers or testing kernel settings, because they can be loaded and unloaded without
rebooting.</p>
</dd>
<dt><b>Library</b></dt>
<dd>
<p>A collection of functions which can be shared between programs.</p>
</dd>
<dt><b>LILO</b></dt>
<dd>
<p>The LInux LOader. LILO is the most widely-used Linux boot manager.</p>
</dd>
<dt><b>LOADLIN</b></dt>
<dd>
<p>LOADLIN is a program that runs under MS DOS or Windows and boots a Linux system. It is
most commonly used on computers with multiple operating systems (including Linux and
DOS/Windows, of course).</p>
</dd>
<dt><b>Man section</b></dt>
<dd>
<p>Pages in the standard Unix online manual ("man") are grouped into sections for easy
reference. All C programming pages are in section 3, system administration pages in
section 5, etc.</p>
</dd>
<dt><b>MBR</b></dt>
<dd>
<p>The Master Boot Record. A reserved space on a hard drive where information on what to
do when booting is stored. LILO or other boot managers can be written here.</p>
</dd>
<dt><b>Motif</b></dt>
<dd>
<p>A popular programming toolkit used in many older X programs.</p>
</dd>
<dt><b>MOTD</b></dt>
<dd>
<p>Message of the Day. The motd (stored in Linux in <tt class="FILENAME">/etc/motd</tt>
is a text file that is displayed to all users upon logging in. Traditionally, it is used
by the system administrator as a sort of “bulletin board” for communicating
with users.</p>
</dd>
<dt><b>Mount point</b></dt>
<dd>
<p>An empty directory in a filesystem where another filesystem is to be
“mounted”, or grafted on.</p>
</dd>
<dt><b>Nameserver</b></dt>
<dd>
<p>A DNS information server. Nameservers translate DNS names to numerical IP
addresses.</p>
</dd>
<dt><b>Network interface</b></dt>
<dd>
<p>A virtual representation of a network device provided by the kernel. Network
interfaces allow users and programs to talk to network devices.</p>
</dd>
<dt><b>NFS</b></dt>
<dd>
<p>The Network Filesystem. NFS allows the mounting of remote filesystems as if they were
local to your computer and thus provides a transparent method of file sharing.</p>
</dd>
<dt><b>Octal</b></dt>
<dd>
<p>Base-8 number system, with digits 0-7.</p>
</dd>
<dt><b>Pager</b></dt>
<dd>
<p>An X program that allows the user to see and switch between multiple
“desktops”.</p>
</dd>
<dt><b>Partition</b></dt>
<dd>
<p>A division of a hard drive. Filesystems exist on top of partitions.</p>
</dd>
<dt><b>PPP</b></dt>
<dd>
<p>Point-to-Point Protocol. PPP is used mainly for connecting via modem to an Internet
Service Provider.</p>
</dd>
<dt><b>Process</b></dt>
<dd>
<p>A running program.</p>
</dd>
<dt><b>Root directory</b></dt>
<dd>
<p>Represented as “/”, the root directory exists at the top of the
filesystem, with all other directories branching out beneath it in a “file
tree”.</p>
</dd>
<dt><b>Root disk</b></dt>
<dd>
<p>The disk (usually fixed) on which the root directory is stored.</p>
</dd>
<dt><b>Routing table</b></dt>
<dd>
<p>The set of information the kernel uses in “routing” network data around.
It contains such tidbits as where your default gateway is, which network interface is
connected to which network, etc.</p>
</dd>
<dt><b>Runlevel</b></dt>
<dd>
<p>The overall system state as defined by init. Runlevel 6 is rebooting, runlevel 1 is
“single user mode”, runlevel 4 is an X login, etc. There are 6 available
runlevels on a Slackware system.</p>
</dd>
<dt><b>Secure shell</b></dt>
<dd>
<p>An encrypted (thus secure) method of logging in remotely to a computer. Many secure
shell programs are available; both a client and server are needed.</p>
</dd>
<dt><b>Service</b></dt>
<dd>
<p>The sharing of information and/or data between programs and computers from a single
“server” to multiple “clients”. HTTP, FTP, NFS, etc. are
services.</p>
</dd>
<dt><b>Shadow password suite</b></dt>
<dd>
<p>The shadow password suite allows encrypted passwords to be hidden from users, while
the rest of the information in the <tt class="FILENAME">/etc/passwd</tt> file remains
visible to all. This helps prevent brute-force attempts at cracking passwords.</p>
</dd>
<dt><b>Shell</b></dt>
<dd>
<p>Shells provide a commandline interface to the user. When you're looking at a text
prompt, you're in a shell.</p>
</dd>
<dt><b>Shell builtin</b></dt>
<dd>
<p>A command built into the shell, as opposed to being provided by an external program.
For instance, <tt class="COMMAND">bash</tt> has a <tt class="COMMAND">cd</tt>
builtin.</p>
</dd>
<dt><b>Signal</b></dt>
<dd>
<p>Unix programs can communicate between each other using simple “signals”,
which are enumerated and usually have specific meanings. <tt class="COMMAND">kill -l</tt>
will list the available signals.</p>
</dd>
<dt><b>SLIP</b></dt>
<dd>
<p>Serial Line Interface Protocol. SLIP is a similar protocol to PPP, in that it's used
for connecting two machines via a serial interface.</p>
</dd>
<dt><b>Software package</b></dt>
<dd>
<p>A program and its associated files, archived and compressed into a single file along
with any necessary scripts or information to aid in managing the installation, upgrade,
and removal of those files.</p>
</dd>
<dt><b>Software series</b></dt>
<dd>
<p>A collection of related software packages in Slackware. All KDE packages are in the
“kde” series, networking packages in the “n” series, etc.</p>
</dd>
<dt><b>Source code</b></dt>
<dd>
<p>The (more or less) human-readable code in which most programs are written. Source code
is compiled into “binary” code.</p>
</dd>
<dt><b>Standard Error (stderr)</b></dt>
<dd>
<p>The Unix-standard output stream for errors. Programs write any error messages on
stderr, so that they can be separated from normal output.</p>
</dd>
<dt><b>Standard Input (stdin)</b></dt>
<dd>
<p>The Unix-standard input stream. Data can be redirected or piped into a program's stdin
from any source.</p>
</dd>
<dt><b>Standard Output (stdout)</b></dt>
<dd>
<p>The Unix-standard output stream. Normal text output from a program is written to
stdout, which is separate from the error messages reported on stderr and can be piped or
redirected into other programs' stdin or to a file.</p>
</dd>
<dt><b>Subnet</b></dt>
<dd>
<p>An IP address range that is part of a larger range. For instance, 192.168.1.0 is a
subnet of 192.168.0.0 (where 0 is a mask meaning “undefined”); it is, in
fact, the “.1” subnet.</p>
</dd>
<dt><b>Superblock</b></dt>
<dd>
<p>In Linux, partitions are discussed in terms of blocks. A block is 512 bytes. The
superblock is the first 512 bytes of a partition.</p>
</dd>
<dt><b>Supplemental disk</b></dt>
<dd>
<p>In Slackware, a floppy disk used during installation that contains neither the kernel
(which is on the boot disk) nor the root filesystem (which is on the root disk), but
additional needed files such as network modules or PCMCIA support.</p>
</dd>
<dt><b>Suspended process</b></dt>
<dd>
<p>A process which has been frozen until killed or resumed.</p>
</dd>
<dt><b>Swap space</b></dt>
<dd>
<p>Disk space used by the kernel as “virtual” RAM. It is slower than RAM, but
because disk space is cheaper, swap is usually more plentiful. Swap space is useful to
the kernel for holding lesser-used data and as a fallback when physical RAM is
exhausted.</p>
</dd>
<dt><b>Symbolic link</b></dt>
<dd>
<p>A special file that simply points to the location of another file. Symbolic links are
used to avoid data duplication when a file is needed in multiple locations.</p>
</dd>
<dt><b>Tagfile</b></dt>
<dd>
<p>A file used by the Slackware <tt class="COMMAND">setup</tt> program during
installation, which describes a set of packages to be installed.</p>
</dd>
<dt><b>Terminal</b></dt>
<dd>
<p>A human-computer interface consisting of at least a screen (or virtual screen) and
some method of input (almost always at least a keyboard).</p>
</dd>
<dt><b>Toolkit, GUI</b></dt>
<dd>
<p>A GUI toolkit is a collection of libraries that provide a programmer with code to draw
“widgets” such as scrollbars, checkboxes, etc. and construct a graphical
interface. The GUI toolkit used by a program often defines its “look and
feel”.</p>
</dd>
<dt><b>UID</b></dt>
<dd>
<p>User Identifier. A unique number that identifies a user to the system. UIDs are used
by most programs instead of usernames because a number is easier to deal with; usernames
are generally only used when the user has to see things happen.</p>
</dd>
<dt><b>VESA</b></dt>
<dd>
<p>Video Electronics Standards Association. The term “VESA” is often used to
denote a standard specified by said Association. Nearly all modern video adapters are
VESA-compliant.</p>
</dd>
<dt><b>Virtual terminal</b></dt>
<dd>
<p>The use of software to simulate multiple terminals while using only a single set of
input/output devices (keyboard, monitor, mouse). Special keystrokes switch between
virtual terminals at a single physical terminal.</p>
</dd>
<dt><b>Window manager</b></dt>
<dd>
<p>An X program whose purpose is to provide a graphical interface beyond the simple
rectangle-drawing of the X Window System. Window managers generally provide titlebars,
menus for running programs, etc.</p>
</dd>
<dt><b>Working directory</b></dt>
<dd>
<p>The directory in which a program considers itself to be while running.</p>
</dd>
<dt><b>Wrapper program</b></dt>
<dd>
<p>A program whose sole purpose is to run other programs, but change their behavior in
some way by altering their environments or filtering their input.</p>
</dd>
<dt><b>X server</b></dt>
<dd>
<p>The program in the X Window System which interfaces with graphics hardware and handles
the actual running of X programs.</p>
</dd>
<dt><b>X Window System</b></dt>
<dd>
<p>Network-oriented graphical interface system used on most Unix-like operating systems,
including Linux.</p>
</dd>
</dl>
</div>
<div class="APPENDIX">
<hr />
<h1><a id="GPL" name="GPL"></a>Appendix A. The GNU General Public License</h1>
<p class="LITERALLAYOUT">GNU GENERAL PUBLIC LICENSE<br />
<br />
Version 2, June 1991<br />
Copyright (C) 1989, 1991 Free Software Foundation, Inc.<br />
59 Temple Place, Suite 330, Boston, MA 02111-1307 USA<br />
Everyone is permitted to copy and distribute verbatim copies of this<br />
license document, but changing it is not allowed.</p>
<div class="SIMPLESECT">
<hr />
<h4 class="SIMPLESECT"><a id="AEN7088" name="AEN7088">A.1. Preamble</a></h4>
<p>The licenses for most software are designed to take away your freedom to share and
change it. By contrast, the GNU General Public License is intended to guarantee your
freedom to share and change free software--to make sure the software is free for all its
users. This General Public License applies to most of the Free Software Foundation's
software and to any other program whose authors commit to using it. (Some other Free
Software Foundation software is covered by the GNU Library General Public License
instead.) You can apply it to your programs, too.</p>
<p>When we speak of free software, we are referring to freedom, not price. Our General
Public Licenses are designed to make sure that you have the freedom to distribute copies
of free software (and charge for this service if you wish), that you receive source code
or can get it if you want it, that you can change the software or use pieces of it in new
free programs; and that you know you can do these things.</p>
<p>To protect your rights, we need to make restrictions that forbid anyone to deny you
these rights or to ask you to surrender the rights. These restrictions translate to
certain responsibilities for you if you distribute copies of the software, or if you
modify it.</p>
<p>For example, if you distribute copies of such a program, whether gratis or for a fee,
you must give the recipients all the rights that you have. You must make sure that they,
too, receive or can get the source code. And you must show them these terms so they know
their rights.</p>
<p>We protect your rights with two steps: (1) copyright the software, and (2) offer you
this license which gives you legal permission to copy, distribute and/or modify the
software.</p>
<p>Also, for each author's protection and ours, we want to make certain that everyone
understands that there is no warranty for this free software. If the software is modified
by someone else and passed on, we want its recipients to know that what they have is not
the original, so that any problems introduced by others will not reflect on the original
authors' reputations.</p>
<p>Finally, any free program is threatened constantly by software patents. We wish to
avoid the danger that redistributors of a free program will individually obtain patent
licenses, in effect making the program proprietary. To prevent this, we have made it
clear that any patent must be licensed for everyone's free use or not licensed at
all.</p>
<p>The precise terms and conditions for copying, distribution and modification
follow.</p>
</div>
<div class="SIMPLESECT">
<hr />
<h4 class="SIMPLESECT"><a id="AEN7098" name="AEN7098">A.2. TERMS AND CONDITIONS</a></h4>
<p><span class="emphasis"><i class="EMPHASIS">TERMS AND CONDITIONS FOR COPYING,
DISTRIBUTION AND MODIFICATION</i></span></p>
<ol type="1">
<li>
<p>This License applies to any program or other work which contains a notice placed by
the copyright holder saying it may be distributed under the terms of this General Public
License. The “Program”, below, refers to any such program or work, and a
“work based on the Program” means either the Program or any derivative work
under copyright law: that is to say, a work containing the Program or a portion of it,
either verbatim or with modifications and/or translated into another language.
(Hereinafter, translation is included without limitation in the term
“modification”.) Each licensee is addressed as “you”.</p>
<p>Activities other than copying, distribution and modification are not covered by this
License; they are outside its scope. The act of running the Program is not restricted,
and the output from the Program is covered only if its contents constitute a work based
on the Program (independent of having been made by running the Program). Whether that is
true depends on what the Program does.</p>
</li>
<li>
<p>You may copy and distribute verbatim copies of the Program's source code as you
receive it, in any medium, provided that you conspicuously and appropriately publish on
each copy an appropriate copyright notice and disclaimer of warranty; keep intact all the
notices that refer to this License and to the absence of any warranty; and give any other
recipients of the Program a copy of this License along with the Program.</p>
<p>You may charge a fee for the physical act of transferring a copy, and you may at your
option offer warranty protection in exchange for a fee.</p>
</li>
<li>
<p>You may modify your copy or copies of the Program or any portion of it, thus forming a
work based on the Program, and copy and distribute such modifications or work under the
terms of Section 1 above, provided that you also meet all of these conditions:</p>
<ol type="a">
<li>
<p>You must cause the modified files to carry prominent notices stating that you changed
the files and the date of any change.</p>
</li>
<li>
<p>You must cause any work that you distribute or publish, that in whole or in part
contains or is derived from the Program or any part thereof, to be licensed as a whole at
no charge to all third parties under the terms of this License.</p>
</li>
<li>
<p>If the modified program normally reads commands interactively when run, you must cause
it, when started running for such interactive use in the most ordinary way, to print or
display an announcement including an appropriate copyright notice and a notice that there
is no warranty (or else, saying that you provide a warranty) and that users may
redistribute the program under these conditions, and telling the user how to view a copy
of this License. (Exception: if the Program itself is interactive but does not normally
print such an announcement, your work based on the Program is not required to print an
announcement.)</p>
</li>
</ol>
<p>These requirements apply to the modified work as a whole. If identifiable sections of
that work are not derived from the Program, and can be reasonably considered independent
and separate works in themselves, then this License, and its terms, do not apply to those
sections when you distribute them as separate works. But when you distribute the same
sections as part of a whole which is a work based on the Program, the distribution of the
whole must be on the terms of this License, whose permissions for other licensees extend
to the entire whole, and thus to each and every part regardless of who wrote it.</p>
<p>Thus, it is not the intent of this section to claim rights or contest your rights to
work written entirely by you; rather, the intent is to exercise the right to control the
distribution of derivative or collective works based on the Program.</p>
<p>In addition, mere aggregation of another work not based on the Program with the
Program (or with a work based on the Program) on a volume of a storage or distribution
medium does not bring the other work under the scope of this License.</p>
</li>
<li>
<p>You may copy and distribute the Program (or a work based on it, under Section 2) in
object code or executable form under the terms of Sections 1 and 2 above provided that
you also do one of the following:</p>
<ol type="a">
<li>
<p>Accompany it with the complete corresponding machine-readable source code, which must
be distributed under the terms of Sections 1 and 2 above on a medium customarily used for
software interchange; or,</p>
</li>
<li>
<p>Accompany it with a written offer, valid for at least three years, to give any third
party, for a charge no more than your cost of physically performing source distribution,
a complete machine-readable copy of the corresponding source code, to be distributed
under the terms of Sections 1 and 2 above on a medium customarily used for software
interchange; or,</p>
</li>
<li>
<p>Accompany it with the information you received as to the offer to distribute
corresponding source code. (This alternative is allowed only for noncommercial
distribution and only if you received the program in object code or executable form with
such an offer, in accord with Subsection b above.)</p>
</li>
</ol>
<p>The source code for a work means the preferred form of the work for making
modifications to it. For an executable work, complete source code means all the source
code for all modules it contains, plus any associated interface definition files, plus
the scripts used to control compilation and installation of the executable. However, as a
special exception, the source code distributed need not include anything that is normally
distributed (in either source or binary form) with the major components (compiler,
kernel, and so on) of the operating system on which the executable runs, unless that
component itself accompanies the executable.</p>
<p>If distribution of executable or object code is made by offering access to copy from a
designated place, then offering equivalent access to copy the source code from the same
place counts as distribution of the source code, even though third parties are not
compelled to copy the source along with the object code.</p>
</li>
<li>
<p>You may not copy, modify, sublicense, or distribute the Program except as expressly
provided under this License. Any attempt otherwise to copy, modify, sublicense or
distribute the Program is void, and will automatically terminate your rights under this
License. However, parties who have received copies, or rights, from you under this
License will not have their licenses terminated so long as such parties remain in full
compliance.</p>
</li>
<li>
<p>You are not required to accept this License, since you have not signed it. However,
nothing else grants you permission to modify or distribute the Program or its derivative
works. These actions are prohibited by law if you do not accept this License. Therefore,
by modifying or distributing the Program (or any work based on the Program), you indicate
your acceptance of this License to do so, and all its terms and conditions for copying,
distributing or modifying the Program or works based on it.</p>
</li>
<li>
<p>Each time you redistribute the Program (or any work based on the Program), the
recipient automatically receives a license from the original licensor to copy, distribute
or modify the Program subject to these terms and conditions. You may not impose any
further restrictions on the recipients' exercise of the rights granted herein. You are
not responsible for enforcing compliance by third parties to this License.</p>
</li>
<li>
<p>If, as a consequence of a court judgment or allegation of patent infringement or for
any other reason (not limited to patent issues), conditions are imposed on you (whether
by court order, agreement or otherwise) that contradict the conditions of this License,
they do not excuse you from the conditions of this License. If you cannot distribute so
as to satisfy simultaneously your obligations under this License and any other pertinent
obligations, then as a consequence you may not distribute the Program at all. For
example, if a patent license would not permit royalty-free redistribution of the Program
by all those who receive copies directly or indirectly through you, then the only way you
could satisfy both it and this License would be to refrain entirely from distribution of
the Program.</p>
<p>If any portion of this section is held invalid or unenforceable under any particular
circumstance, the balance of the section is intended to apply and the section as a whole
is intended to apply in other circumstances.</p>
<p>It is not the purpose of this section to induce you to infringe any patents or other
property right claims or to contest validity of any such claims; this section has the
sole purpose of protecting the integrity of the free software distribution system, which
is implemented by public license practices. Many people have made generous contributions
to the wide range of software distributed through that system in reliance on consistent
application of that system; it is up to the author/donor to decide if he or she is
willing to distribute software through any other system and a licensee cannot impose that
choice.</p>
<p>This section is intended to make thoroughly clear what is believed to be a consequence
of the rest of this License.</p>
</li>
<li>
<p>If the distribution and/or use of the Program is restricted in certain countries
either by patents or by copyrighted interfaces, the original copyright holder who places
the Program under this License may add an explicit geographical distribution limitation
excluding those countries, so that distribution is permitted only in or among countries
not thus excluded. In such case, this License incorporates the limitation as if written
in the body of this License.</p>
</li>
<li>
<p>The Free Software Foundation may publish revised and/or new versions of the General
Public License from time to time. Such new versions will be similar in spirit to the
present version, but may differ in detail to address new problems or concerns.</p>
<p>Each version is given a distinguishing version number. If the Program specifies a
version number of this License which applies to it and “any later version”,
you have the option of following the terms and conditions either of that version or of
any later version published by the Free Software Foundation. If the Program does not
specify a version number of this License, you may choose any version ever published by
the Free Software Foundation.</p>
</li>
<li>
<p>If you wish to incorporate parts of the Program into other free programs whose
distribution conditions are different, write to the author to ask for permission. For
software which is copyrighted by the Free Software Foundation, write to the Free Software
Foundation; we sometimes make exceptions for this. Our decision will be guided by the two
goals of preserving the free status of all derivatives of our free software and of
promoting the sharing and reuse of software generally.</p>
</li>
<li>
<p>NO WARRANTY</p>
<p>BECAUSE THE PROGRAM IS LICENSED FREE OF CHARGE, THERE IS NO WARRANTY FOR THE PROGRAM,
TO THE EXTENT PERMITTED BY APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE
COPYRIGHT HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM “AS IS” WITHOUT
WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE
RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU. SHOULD THE PROGRAM
PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL NECESSARY SERVICING, REPAIR OR
CORRECTION.</p>
</li>
<li>
<p>IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING WILL ANY
COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MAY MODIFY AND/OR REDISTRIBUTE THE PROGRAM AS
PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL
OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE THE PROGRAM
(INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA BEING RENDERED INACCURATE OR LOSSES
SUSTAINED BY YOU OR THIRD PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER
PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
DAMAGES.</p>
</li>
</ol>
<p>END OF TERMS AND CONDITIONS</p>
</div>
<div class="SIMPLESECT">
<hr />
<h4 class="SIMPLESECT"><a id="AEN7162" name="AEN7162">A.3. How to Apply These Terms to
Your New Programs</a></h4>
<p>If you develop a new program, and you want it to be of the greatest possible use to
the public, the best way to achieve this is to make it free software which everyone can
redistribute and change under these terms.</p>
<p>To do so, attach the following notices to the program. It is safest to attach them to
the start of each source file to most effectively convey the exclusion of warranty; and
each file should have at least the “copyright” line and a pointer to where
the full notice is found.</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="PROGRAMLISTING">
<one line to give the program's name and a brief idea of what it does.>
Copyright (C) <year> <name of author>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
</pre>
</td>
</tr>
</table>
<p>Also add information on how to contact you by electronic and paper mail.</p>
<p>If the program is interactive, make it output a short notice like this when it starts
in an interactive mode:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="SCREEN">
Gnomovision version 69, Copyright (C) year name of author
Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
This is free software, and you are welcome to redistribute it
under certain conditions; type `show c' for details.
</pre>
</td>
</tr>
</table>
<p>The hypothetical commands `show w' and `show c' should show the appropriate parts of
the General Public License. Of course, the commands you use may be called something other
than `show w' and `show c'; they could even be mouse-clicks or menu items--whatever suits
your program.</p>
<p>You should also get your employer (if you work as a programmer) or your school, if
any, to sign a “copyright disclaimer” for the program, if necessary. Here is
a sample; alter the names:</p>
<table border="0" bgcolor="#E0E0E0" width="100%">
<tr>
<td>
<pre class="PROGRAMLISTING">
Yoyodyne, Inc., hereby disclaims all copyright interest in the program
`Gnomovision' (which makes passes at compilers) written by James Hacker.
<signature of Ty Coon>, 1 April 1989
Ty Coon, President of Vice
</pre>
</td>
</tr>
</table>
<p>This General Public License does not permit incorporating your program into
proprietary programs. If your program is a subroutine library, you may consider it more
useful to permit linking proprietary applications with the library. If this is what you
want to do, use the GNU Library General Public License instead of this License.</p>
</div>
</div>
</div>
<hr />
</body>
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