diff options
| author |   Patrick J Volkerding <volkerdi@slackware.com> | 2009-08-26 10:00:38 -0500 |
|---|---|---|
| committer |   Eric Hameleers <alien@slackware.com> | 2018-05-31 22:41:17 +0200 |
| commit | 5a12e7c134274dba706667107d10d231517d3e05 (patch) | |
| tree | 55718d5acb710fde798d9f38d0bbaf594ed4b296 /slackbook/html/essential-sysadmin-shutdown.html | |
| download | current-slackware-13.0.tar.gz current-slackware-13.0.tar.xz | |
Slackware 13.0slackware-13.0
Wed Aug 26 10:00:38 CDT 2009
Slackware 13.0 x86_64 is released as stable! Thanks to everyone who
helped make this release possible -- see the RELEASE_NOTES for the
credits. The ISOs are off to the replicator. This time it will be a
6 CD-ROM 32-bit set and a dual-sided 32-bit/64-bit x86/x86_64 DVD.
We're taking pre-orders now at store.slackware.com. Please consider
picking up a copy to help support the project. Once again, thanks to
the entire Slackware community for all the help testing and fixing
things and offering suggestions during this development cycle.
As always, have fun and enjoy! -P.
Diffstat (limited to 'slackbook/html/essential-sysadmin-shutdown.html')
| -rw-r--r-- | slackbook/html/essential-sysadmin-shutdown.html | 236 |
1 files changed, 236 insertions, 0 deletions
diff --git a/slackbook/html/essential-sysadmin-shutdown.html b/slackbook/html/essential-sysadmin-shutdown.html new file mode 100644 index 000000000..a97c78f6d --- /dev/null +++ b/slackbook/html/essential-sysadmin-shutdown.html @@ -0,0 +1,236 @@ +<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" + "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> +<html xmlns="http://www.w3.org/1999/xhtml"> +<head> +<meta name="generator" content="HTML Tidy, see www.w3.org" /> +<title>Shutting Down Properly</title> +<meta name="GENERATOR" content="Modular DocBook HTML Stylesheet Version 1.7" /> +<link rel="HOME" title="Slackware Linux Essentials" href="index.html" /> +<link rel="UP" title="Essential System Administration" href="essential-sysadmin.html" /> +<link rel="PREVIOUS" title="Users and Groups, the Hard Way" +href="essential-sysadmin-hardusers.html" /> +<link rel="NEXT" title="Basic Network Commands" href="basic-network-commands.html" /> +<link rel="STYLESHEET" type="text/css" href="docbook.css" /> +<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" /> +</head> +<body class="SECT1" bgcolor="#FFFFFF" text="#000000" link="#0000FF" vlink="#840084" +alink="#0000FF"> +<div class="NAVHEADER"> +<table summary="Header navigation table" width="100%" border="0" cellpadding="0" +cellspacing="0"> +<tr> +<th colspan="3" align="center">Slackware Linux Essentials</th> +</tr> + +<tr> +<td width="10%" align="left" valign="bottom"><a href="essential-sysadmin-hardusers.html" +accesskey="P">Prev</a></td> +<td width="80%" align="center" valign="bottom">Chapter 12 Essential System +Administration</td> +<td width="10%" align="right" valign="bottom"><a href="basic-network-commands.html" +accesskey="N">Next</a></td> +</tr> +</table> + +<hr align="LEFT" width="100%" /> +</div> + +<div class="SECT1"> +<h1 class="SECT1"><a id="ESSENTIAL-SYSADMIN-SHUTDOWN" +name="ESSENTIAL-SYSADMIN-SHUTDOWN">12.3 Shutting Down Properly</a></h1> + +<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 class="NAVFOOTER"> +<hr align="LEFT" width="100%" /> +<table summary="Footer navigation table" width="100%" border="0" cellpadding="0" +cellspacing="0"> +<tr> +<td width="33%" align="left" valign="top"><a href="essential-sysadmin-hardusers.html" +accesskey="P">Prev</a></td> +<td width="34%" align="center" valign="top"><a href="index.html" +accesskey="H">Home</a></td> +<td width="33%" align="right" valign="top"><a href="basic-network-commands.html" +accesskey="N">Next</a></td> +</tr> + +<tr> +<td width="33%" align="left" valign="top">Users and Groups, the Hard Way</td> +<td width="34%" align="center" valign="top"><a href="essential-sysadmin.html" +accesskey="U">Up</a></td> +<td width="33%" align="right" valign="top">Basic Network Commands</td> +</tr> +</table> +</div> +</body> +</html> + |