man/elogind.syntax.xml

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  10 <refentry id="elogind.syntax">
  11
  12   <refentryinfo>
  13     <title>elogind.syntax</title>
  14     <productname>elogind</productname>
  15
  16     <authorgroup>
  17       <author>
  18         <contrib>A. U. Thor</contrib>
  19         <firstname>Zbigniew</firstname>
  20         <surname>Jędrzejewski-Szmek</surname>
  21         <email>zbyszek@in.waw.pl</email>
  22       </author>
  23     </authorgroup>
  24   </refentryinfo>
  25
  26   <refmeta>
  27     <refentrytitle>elogind.syntax</refentrytitle>
  28     <manvolnum>7</manvolnum>
  29   </refmeta>
  30
  31   <refnamediv>
  32     <refname>elogind.syntax</refname>
  33     <refpurpose>General syntax of elogind configuration files</refpurpose>
  34   </refnamediv>
  35
  36   <refsect1>
  37     <title>Introduction</title>
  38
  39     <para>This page describes the basic principles of configuration files used by
  40     <citerefentry><refentrytitle>elogind</refentrytitle><manvolnum>1</manvolnum></citerefentry>
  41     and related programs for:
  42     <itemizedlist>
  43       <listitem><para>elogind unit files, see
  44       <citerefentry><refentrytitle>elogind.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
  45       <citerefentry><refentrytitle>elogind.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
  46       <citerefentry><refentrytitle>elogind.socket</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
  47       <citerefentry><refentrytitle>elogind.device</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
  48       <citerefentry><refentrytitle>elogind.mount</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
  49       <citerefentry><refentrytitle>elogind.automount</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
  50       <citerefentry><refentrytitle>elogind.swap</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
  51       <citerefentry><refentrytitle>elogind.target</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
  52       <citerefentry><refentrytitle>elogind.path</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
  53       <citerefentry><refentrytitle>elogind.timer</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
  54       <citerefentry><refentrytitle>elogind.slice</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
  55       <citerefentry><refentrytitle>elogind.scope</refentrytitle><manvolnum>5</manvolnum></citerefentry></para></listitem>
  56
  57       <listitem><para>daemon config files, see
  58       <citerefentry><refentrytitle>elogind-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
  59       <citerefentry><refentrytitle>elogind-user.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
  60       <citerefentry><refentrytitle>logind.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
  61       <citerefentry><refentrytitle>journald.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
  62       <citerefentry><refentrytitle>journal-remote.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
  63       <citerefentry><refentrytitle>journal-upload.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
  64       <citerefentry><refentrytitle>elogind-sleep.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
  65       <citerefentry><refentrytitle>timesyncd.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>
  66       </para></listitem>
  67     </itemizedlist>
  68     </para>
  69
  70     <para>The syntax is inspired by
  71     <ulink url="http://standards.freedesktop.org/desktop-entry-spec/latest/">XDG Desktop Entry Specification</ulink>
  72     <filename>.desktop</filename> files, which are in turn inspired by Microsoft Windows
  73     <filename>.ini</filename> files.
  74     </para>
  75
  76     <para>Each file is a plain text file divided into sections, with configuration entries in the
  77     style <replaceable>key</replaceable>=<replaceable>value</replaceable>.
  78     Empty lines and lines starting with <literal>#</literal> or <literal>;</literal> are
  79     ignored, which may be used for commenting.</para>
  80
  81     <para>Lines ending in a backslash are concatenated with the following line while reading and the
  82     backslash is replaced by a space character. This may be used to wrap long lines. The limit on
  83     line length is very large (currently 1 MB), but it is recommended to avoid such long lines and
  84     use multiple directives, variable substitution, or other mechanism as appropriate for the given
  85     file type.</para>
  86
  87     <example><programlisting>[Section A]
  88 KeyOne=value 1
  89 KeyTwo=value 2
  90
  91 # a comment
  92
  93 [Section B]
  94 Setting="something" "some thing" "…"
  95 KeyTwo=value 2 \
  96        value 2 continued
  97 </programlisting></example>
  98
  99     <para>Various settings are allowed to be specified more than once, in which case the
 100     interpretation depends on the setting. Often, multiple settings form a list, and setting to an
 101     empty value "resets", which means that previous assignments are ignored. When this is allowed,
 102     it is mentioned in the description of the setting. Note that using multiple assignments to the
 103     same value makes the file incompatible with parsers for the XDG <filename>.desktop</filename>
 104     file format.</para>
 105   </refsect1>
 106
 107 </refentry>