source: postlfs/config/logon.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE sect1 PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
   "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
  <!ENTITY % general-entities SYSTEM "../../general.ent">
  %general-entities;
]>

<sect1 id="postlfs-config-logon" xreflabel="Customizing your Logon with /etc/issue">
  <?dbhtml filename="logon.html"?>


  <title>Customizing your Logon with /etc/issue</title>

  <indexterm zone="postlfs-config-logon">
    <primary sortas="e-etc-issue">/etc/issue</primary>
  </indexterm>

  <para>
    When you first boot up your new LFS system, the logon screen will be
    nice and plain (as it should be in a bare-bones system).  Many people
    however, will want their system to display some information in the logon
    message.  This can be accomplished using the
    file <filename>/etc/issue</filename>.
  </para>

  <para>
    The <filename>/etc/issue</filename> file is a plain text file
    which will also accept certain escape sequences (see below) in order to
    insert information about the system.  There is also the file
    <filename>issue.net</filename> which can be used when logging on remotely.
    <command>ssh</command> however, will only use it if you set the option in
    the configuration file and will <emphasis>not</emphasis> interpret the
    escape sequences shown below.
  </para>

  <para>
    One of the most common things which people want to do is clear the
    screen at each logon.  The easiest way of doing that is to put a "clear"
    escape sequence into <filename>/etc/issue</filename>.  A simple way of
    doing this is to issue the command <command>clear &gt;
    /etc/issue</command>.  This will insert the relevant escape code into
    the start of the <filename>/etc/issue</filename> file.  Note that if
    you do this, when you edit the file, you should leave the characters
    (normally '^[[H^[[2J') on the first line alone.
  </para>

  <note>
    <para>
      Terminal escape sequences are special codes recognized by the terminal.
      The ^[ represents an ASCII ESC character.  The sequence ESC [ H
      puts the cursor in the upper left hand corner of the screen and ESC 2 J
      erases the screen.  For more information on terminal escape sequences see
      <ulink url='https://invisible-mirror.net/xterm/ctlseqs/ctlseqs.html'/>
    </para>
  </note>

  <para>
    The following sequences are recognized by <command>agetty</command>
    (the program which usually parses <filename>/etc/issue</filename>).  This
    information is from <command>man agetty</command> where you can find
    extra information about the logon process.
  </para>

  <para>
    The <filename>issue</filename> file can contain certain character
    sequences to display various information.  All <filename>issue</filename>
    sequences consist of a backslash (\) immediately followed by one of the
    letters explained below (so <option>\d</option> in
    <filename>/etc/issue</filename> would insert the current date).
  </para>

<screen><literal>b   Insert the baudrate of the current line.
d   Insert the current date.
s   Insert the system name, the name of the operating system.
l   Insert the name of the current tty line.
m   Insert the architecture identifier of the machine, e.g., i686.
n   Insert the nodename of the machine, also known as the hostname.
o   Insert the domainname of the machine.
r   Insert the release number of the kernel, e.g., 2.6.11.12.
t   Insert the current time.
u   Insert the number of current users logged in.
U   Insert the string "1 user" or "&lt;n&gt; users" where &lt;n&gt; is the
    number of current users logged in.
v   Insert the version of the OS, e.g., the build-date etc.</literal></screen>

</sect1>