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
  12   the Free Software Foundation; either version 2.1 of the License, or
  13   (at your option) any later version.
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  15   systemd is distributed in the hope that it will be useful, but
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  17   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  18   Lesser General Public License for more details.
  19
  20   You should have received a copy of the GNU Lesser General Public License
  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
  61                 be used to write on disk any transient machine ID
  62                 mounted as a temporary file system in
  63                 <filename>/etc/machine-id</filename> at boot time. See
  64                 <citerefentry><refentrytitle>machine-id</refentrytitle><manvolnum>5</manvolnum></citerefentry>
  65                 for more information about this file.</para>
  66
  67                 <para>This tool will execute no operation if
  68                 <filename>/etc/machine-id</filename> doesn't contain any
  69                 valid machine ID, isn't mounted as an independent temporary
  70                             file system, of <filename>/etc</filename> is read-only. If
  71                 those conditions are met, it will then write current machine ID
  72                 to disk and unmount the transient
  73                 <filename>/etc/machine-id</filename> file in a race-free
  74                 manner to ensure that this file is always valid for other
  75                 processes.</para>
  76
  77                 <para>Note that the traditional way to initialize the machine
  78                 ID in <filename>/etc/machine-id</filename> is to use
  79                 <command>systemd-machine-id-setup</command> by system
  80                 installer tools. You can also use
  81                 <citerefentry><refentrytitle>systemd-firstboot</refentrytitle><manvolnum>1</manvolnum></citerefentry>
  82                 to initialize the machine ID on mounted (but not
  83                 booted) system images.</para>
  84         </refsect1>
  85
  86         <refsect1>
  87                 <title>Options</title>
  88
  89                 <para>The following options are understood:</para>
  90
  91                 <variablelist>
  92                         <varlistentry>
  93                                 <term><option>--root=<replaceable>root</replaceable></option></term>
  94                                 <listitem><para>Takes a directory path
  95                                 as an argument. All paths will be
  96                                 prefixed with the given alternate
  97                                 <replaceable>root</replaceable> path,
  98                                 including config search paths.
  99                                 </para></listitem>
 100                         </varlistentry>
 101                         <xi:include href="standard-options.xml" xpointer="help" />
 102                         <xi:include href="standard-options.xml" xpointer="version" />
 103                 </variablelist>
 104
 105         </refsect1>
 106
 107         <refsect1>
 108                 <title>Exit status</title>
 109
 110                 <para>On success, 0 is returned, a non-zero failure
 111                 code otherwise.</para>
 112         </refsect1>
 113
 114         <refsect1>
 115                 <title>See Also</title>
 116                 <para>
 117                         <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 118                         <citerefentry><refentrytitle>systemd-machine-id-commit.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 119                         <citerefentry><refentrytitle>systemd-machine-id-setup</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 120                         <citerefentry><refentrytitle>machine-id</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 121                         <citerefentry><refentrytitle>systemd-firstboot</refentrytitle><manvolnum>1</manvolnum></citerefentry>
 122                 </para>
 123         </refsect1>
 124
 125 </refentry>