<!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>Virtual Terminals</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="The Shell" href="shell.html" />
<link rel="PREVIOUS" title="The Bourne Again Shell (bash)" href="shell-bash.html" />
<link rel="NEXT" title="Filesystem Structure" href="filesystem-structure.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="shell-bash.html"
accesskey="P">Prev</a></td>
<td width="80%" align="center" valign="bottom">Chapter 8 The Shell</td>
<td width="10%" align="right" valign="bottom"><a href="filesystem-structure.html"
accesskey="N">Next</a></td>
</tr>
</table>
<hr align="LEFT" width="100%" />
</div>
<div class="SECT1">
<h1 class="SECT1"><a id="SHELL-VT" name="SHELL-VT">8.4 Virtual Terminals</a></h1>
<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">
<h2 class="SECT2"><a id="AEN3024" name="AEN3024">8.4.1 Screen</a></h2>
<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 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="shell-bash.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="filesystem-structure.html"
accesskey="N">Next</a></td>
</tr>
<tr>
<td width="33%" align="left" valign="top">The Bourne Again Shell (bash)</td>
<td width="34%" align="center" valign="top"><a href="shell.html"
accesskey="U">Up</a></td>
<td width="33%" align="right" valign="top">Filesystem Structure</td>
</tr>
</table>
</div>
</body>
</html>
