<?xml version='1.0'?> <!--*-nxml-*--> <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> <!-- This file is part of systemd. Copyright 2014 Didier Roche systemd is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. systemd is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with systemd; If not, see <http://www.gnu.org/licenses/>. --> <refentry id="systemd-machine-id-commit" xmlns:xi="http://www.w3.org/2001/XInclude"> <refentryinfo> <title>systemd-machine-id-commit</title> <productname>systemd</productname> <authorgroup> <author> <contrib>Developer</contrib> <firstname>Didier</firstname> <surname>Roche</surname> <email>didrocks@ubuntu.com</email> </author> </authorgroup> </refentryinfo> <refmeta> <refentrytitle>systemd-machine-id-commit</refentrytitle> <manvolnum>1</manvolnum> </refmeta> <refnamediv> <refname>systemd-machine-id-commit</refname> <refpurpose>Commit transient machine ID to /etc/machine-id</refpurpose> </refnamediv> <refsynopsisdiv> <cmdsynopsis> <command>systemd-machine-id-commit</command> </cmdsynopsis> </refsynopsisdiv> <refsect1> <title>Description</title> <para><command>systemd-machine-id-commit</command> may be used to write on disk any transient machine ID mounted as a temporary file system in <filename>/etc/machine-id</filename> at boot time. See <citerefentry><refentrytitle>machine-id</refentrytitle><manvolnum>5</manvolnum></citerefentry> for more information about this file.</para> <para>This tool will execute no operation if <filename>/etc/machine-id</filename> doesn't contain any valid machine ID, isn't mounted as an independent temporary file system, of <filename>/etc</filename> is read-only. If those conditions are met, it will then write current machine ID to disk and unmount the transient <filename>/etc/machine-id</filename> file in a race-free manner to ensure that this file is always valid for other processes.</para> <para>Note that the traditional way to initialize the machine ID in <filename>/etc/machine-id</filename> is to use <command>systemd-machine-id-setup</command> by system installer tools. You can also use <citerefentry><refentrytitle>systemd-firstboot</refentrytitle><manvolnum>1</manvolnum></citerefentry> to initialize the machine ID on mounted (but not booted) system images.</para> </refsect1> <refsect1> <title>Options</title> <para>The following options are understood:</para> <variablelist> <varlistentry> <term><option>--root=<replaceable>root</replaceable></option></term> <listitem><para>Takes a directory path as an argument. All paths will be prefixed with the given alternate <replaceable>root</replaceable> path, including config search paths. </para></listitem> </varlistentry> <xi:include href="standard-options.xml" xpointer="help" /> <xi:include href="standard-options.xml" xpointer="version" /> </variablelist> </refsect1> <refsect1> <title>Exit status</title> <para>On success, 0 is returned, a non-zero failure code otherwise.</para> </refsect1> <refsect1> <title>See Also</title> <para> <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, <citerefentry><refentrytitle>systemd-machine-id-commit.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>, <citerefentry><refentrytitle>systemd-machine-id-setup</refentrytitle><manvolnum>1</manvolnum></citerefentry>, <citerefentry><refentrytitle>machine-id</refentrytitle><manvolnum>5</manvolnum></citerefentry>, <citerefentry><refentrytitle>systemd-firstboot</refentrytitle><manvolnum>1</manvolnum></citerefentry> </para> </refsect1> </refentry>