man/systemd-machine-id-commit.xml

   1 <?xml version='1.0'?> <!--*-nxml-*-->
   2 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
   3   "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
   4
   5 <!--
   6   This file is part of systemd.
   7
   8   Copyright 2014 Didier Roche
   9
  10   systemd is free software; you can redistribute it and/or modify it
  11   under the terms of the GNU Lesser General Public License as published by
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  21   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  22 -->
  23
  24 <refentry id="systemd-machine-id-commit"
  25     xmlns:xi="http://www.w3.org/2001/XInclude">
  26
  27   <refentryinfo>
  28     <title>systemd-machine-id-commit</title>
  29     <productname>systemd</productname>
  30
  31     <authorgroup>
  32       <author>
  33         <contrib>Developer</contrib>
  34         <firstname>Didier</firstname>
  35         <surname>Roche</surname>
  36         <email>didrocks@ubuntu.com</email>
  37       </author>
  38     </authorgroup>
  39   </refentryinfo>
  40
  41   <refmeta>
  42     <refentrytitle>systemd-machine-id-commit</refentrytitle>
  43     <manvolnum>1</manvolnum>
  44   </refmeta>
  45
  46   <refnamediv>
  47     <refname>systemd-machine-id-commit</refname>
  48     <refpurpose>Commit transient machine ID to /etc/machine-id</refpurpose>
  49   </refnamediv>
  50
  51   <refsynopsisdiv>
  52     <cmdsynopsis>
  53       <command>systemd-machine-id-commit</command>
  54     </cmdsynopsis>
  55   </refsynopsisdiv>
  56
  57   <refsect1>
  58     <title>Description</title>
  59
  60     <para><command>systemd-machine-id-commit</command> may be used to
  61     write on disk any transient machine ID mounted as a temporary file
  62     system in <filename>/etc/machine-id</filename> at boot time. See
  63     <citerefentry><refentrytitle>machine-id</refentrytitle><manvolnum>5</manvolnum></citerefentry>
  64     for more information about this file.</para>
  65
  66     <para>This tool will execute no operation if
  67     <filename>/etc/machine-id</filename> doesn't contain any valid
  68     machine ID, isn't mounted as an independent temporary file system,
  69     of <filename>/etc</filename> is read-only. If those conditions are
  70     met, it will then write current machine ID to disk and unmount the
  71     transient <filename>/etc/machine-id</filename> file in a race-free
  72     manner to ensure that this file is always valid for other
  73     processes.</para>
  74
  75     <para>Note that the traditional way to initialize the machine ID
  76     in <filename>/etc/machine-id</filename> is to use
  77     <command>systemd-machine-id-setup</command> by system installer
  78     tools. You can also use
  79     <citerefentry><refentrytitle>systemd-firstboot</refentrytitle><manvolnum>1</manvolnum></citerefentry>
  80     to initialize the machine ID on mounted (but not booted) system
  81     images.</para>
  82   </refsect1>
  83
  84   <refsect1>
  85     <title>Options</title>
  86
  87     <para>The following options are understood:</para>
  88
  89     <variablelist>
  90       <varlistentry>
  91         <term><option>--root=<replaceable>root</replaceable></option></term>
  92         <listitem><para>Takes a directory path
  93         as an argument. All paths will be
  94         prefixed with the given alternate
  95         <replaceable>root</replaceable> path,
  96         including config search paths.
  97         </para></listitem>
  98       </varlistentry>
  99       <xi:include href="standard-options.xml" xpointer="help" />
 100       <xi:include href="standard-options.xml" xpointer="version" />
 101     </variablelist>
 102
 103   </refsect1>
 104
 105   <refsect1>
 106     <title>Exit status</title>
 107
 108     <para>On success, 0 is returned, a non-zero failure code
 109     otherwise.</para>
 110   </refsect1>
 111
 112   <refsect1>
 113     <title>See Also</title>
 114     <para>
 115       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 116       <citerefentry><refentrytitle>systemd-machine-id-commit.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 117       <citerefentry><refentrytitle>systemd-machine-id-setup</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 118       <citerefentry><refentrytitle>machine-id</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 119       <citerefentry><refentrytitle>systemd-firstboot</refentrytitle><manvolnum>1</manvolnum></citerefentry>
 120     </para>
 121   </refsect1>
 122
 123 </refentry>