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<?xml version="1.0" encoding='UTF-8'?>
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.3//EN"
"http://www.oasis-open.org/docbook/xml/4.3/docbookx.dtd">
<refentry id="pam_motd">
<refmeta>
<refentrytitle>pam_motd</refentrytitle>
<manvolnum>8</manvolnum>
<refmiscinfo class="sectdesc">Linux-PAM Manual</refmiscinfo>
</refmeta>
<refnamediv id="pam_motd-name">
<refname>pam_motd</refname>
<refpurpose>Display the motd file</refpurpose>
</refnamediv>
<refsynopsisdiv>
<cmdsynopsis id="pam_motd-cmdsynopsis">
<command>pam_motd.so</command>
<arg choice="opt">
motd=<replaceable>/path/filename</replaceable>
</arg>
<arg choice="opt">
motd_dir=<replaceable>/path/dirname.d</replaceable>
</arg>
</cmdsynopsis>
</refsynopsisdiv>
<refsect1 id="pam_motd-description">
<title>DESCRIPTION</title>
<para>
pam_motd is a PAM module that can be used to display
arbitrary motd (message of the day) files after a successful
login. By default, pam_motd shows files in the
following locations:
</para>
<para>
<simplelist type='vert'>
<member><filename>/etc/motd</filename></member>
<member><filename>/run/motd</filename></member>
<member><filename>/usr/lib/motd</filename></member>
<member><filename>/etc/motd.d/</filename></member>
<member><filename>/run/motd.d/</filename></member>
<member><filename>/usr/lib/motd.d/</filename></member>
</simplelist>
</para>
<para>
Each message size is limited to 64KB.
</para>
<para>
If <filename>/etc/motd</filename> does not exist,
then <filename>/run/motd</filename> is shown. If
<filename>/run/motd</filename> does not exist, then
<filename>/usr/lib/motd</filename> is shown.
</para>
<para>
Similar overriding behavior applies to the directories.
Files in <filename>/etc/motd.d/</filename> override files
with the same name in <filename>/run/motd.d/</filename> and
<filename>/usr/lib/motd.d/</filename>. Files in <filename>/run/motd.d/</filename>
override files with the same name in <filename>/usr/lib/motd.d/</filename>.
</para>
<para>
Files in the directories listed above are displayed in lexicographic
order by name. Moreover, the files are filtered by reading them with the
credentials of the target user authenticating on the system.
</para>
<para>
To silence a message,
a symbolic link with target <filename>/dev/null</filename>
may be placed in <filename>/etc/motd.d</filename> with
the same filename as the message to be silenced. Example:
Creating a symbolic link as follows silences <filename>/usr/lib/motd.d/my_motd</filename>.
</para>
<para>
<command>ln -s /dev/null /etc/motd.d/my_motd</command>
</para>
<para>
The <emphasis remap='B'>MOTD_SHOWN=pam</emphasis> environment variable
is set after showing the motd files, even when all of them were silenced
using symbolic links.
</para>
</refsect1>
<refsect1 id="pam_motd-options">
<title>OPTIONS</title>
<variablelist>
<varlistentry>
<term>
<option>motd=<replaceable>/path/filename</replaceable></option>
</term>
<listitem>
<para>
The <filename>/path/filename</filename> file is displayed
as message of the day. Multiple paths to try can be
specified as a colon-separated list. By default this option
is set to <filename>/etc/motd:/run/motd:/usr/lib/motd</filename>.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>motd_dir=<replaceable>/path/dirname.d</replaceable></option>
</term>
<listitem>
<para>
The <filename>/path/dirname.d</filename> directory is scanned
and each file contained inside of it is displayed. Multiple
directories to scan can be specified as a colon-separated list.
By default this option is set to <filename>/etc/motd.d:/run/motd.d:/usr/lib/motd.d</filename>.
</para>
</listitem>
</varlistentry>
</variablelist>
<para>
When no options are given, the default behavior applies for both
options. Specifying either option (or both) will disable the
default behavior for both options.
</para>
</refsect1>
<refsect1 id="pam_motd-types">
<title>MODULE TYPES PROVIDED</title>
<para>
Only the <option>session</option> module type is provided.
</para>
</refsect1>
<refsect1 id='pam_motd-return_values'>
<title>RETURN VALUES</title>
<variablelist>
<varlistentry>
<term>PAM_ABORT</term>
<listitem>
<para>
Not all relevant data or options could be obtained.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>PAM_BUF_ERR</term>
<listitem>
<para>
Memory buffer error.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>PAM_IGNORE</term>
<listitem>
<para>
This is the default return value of this module.
</para>
</listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1 id='pam_motd-examples'>
<title>EXAMPLES</title>
<para>
The suggested usage for <filename>/etc/pam.d/login</filename> is:
<programlisting>
session optional pam_motd.so
</programlisting>
</para>
<para>
To use a <filename>motd</filename> file from a different location:
<programlisting>
session optional pam_motd.so motd=/elsewhere/motd
</programlisting>
</para>
<para>
To use a <filename>motd</filename> file from elsewhere, along with a
corresponding <filename>.d</filename> directory:
<programlisting>
session optional pam_motd.so motd=/elsewhere/motd motd_dir=/elsewhere/motd.d
</programlisting>
</para>
</refsect1>
<refsect1 id='pam_motd-see_also'>
<title>SEE ALSO</title>
<para>
<citerefentry>
<refentrytitle>motd</refentrytitle><manvolnum>5</manvolnum>
</citerefentry>,
<citerefentry>
<refentrytitle>pam.conf</refentrytitle><manvolnum>5</manvolnum>
</citerefentry>,
<citerefentry>
<refentrytitle>pam.d</refentrytitle><manvolnum>5</manvolnum>
</citerefentry>,
<citerefentry>
<refentrytitle>pam</refentrytitle><manvolnum>8</manvolnum>
</citerefentry>
</para>
</refsect1>
<refsect1 id='pam_motd-author'>
<title>AUTHOR</title>
<para>
pam_motd was written by Ben Collins <bcollins@debian.org>.
</para>
<para>
The <option>motd_dir=</option> option was added by
Allison Karlitskaya <allison.karlitskaya@redhat.com>.
</para>
</refsect1>
</refentry>
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