man/systemd-id128.xml

   1 <?xml version='1.0'?> <!--*-nxml-*-->
   2 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
   3   "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
   4 <!-- SPDX-License-Identifier: LGPL-2.1+ -->
   5
   6 <refentry id="systemd-id128" xmlns:xi="http://www.w3.org/2001/XInclude">
   7
   8   <refentryinfo>
   9     <title>systemd-id128</title>
  10     <productname>systemd</productname>
  11   </refentryinfo>
  12
  13   <refmeta>
  14     <refentrytitle>systemd-id128</refentrytitle>
  15     <manvolnum>1</manvolnum>
  16   </refmeta>
  17
  18   <refnamediv>
  19     <refname>systemd-id128</refname>
  20     <refpurpose>Generate and print sd-128 identifiers</refpurpose>
  21   </refnamediv>
  22
  23   <refsynopsisdiv>
  24     <cmdsynopsis>
  25       <command>systemd-id128</command>
  26       <arg choice="opt" rep="repeat">OPTIONS</arg>
  27       <arg choice="plain">new</arg>
  28     </cmdsynopsis>
  29
  30     <cmdsynopsis>
  31       <command>systemd-id128</command>
  32       <arg choice="opt" rep="repeat">OPTIONS</arg>
  33       <arg choice="plain">machine-id</arg>
  34     </cmdsynopsis>
  35
  36     <cmdsynopsis>
  37       <command>systemd-id128</command>
  38       <arg choice="opt" rep="repeat">OPTIONS</arg>
  39       <arg choice="plain">boot-id</arg>
  40     </cmdsynopsis>
  41
  42     <cmdsynopsis>
  43       <command>systemd-id128</command>
  44       <arg choice="opt" rep="repeat">OPTIONS</arg>
  45       <arg choice="plain">invocation-id</arg>
  46     </cmdsynopsis>
  47   </refsynopsisdiv>
  48
  49   <refsect1>
  50     <title>Description</title>
  51
  52     <para><command>id128</command> may be used to conveniently print
  53     <citerefentry><refentrytitle>sd-id128</refentrytitle><manvolnum>3</manvolnum></citerefentry>
  54     UUIDs. What identifier is printed depends on the specific verb.</para>
  55
  56     <para>With <command>new</command>, a new random identifier will be generated.</para>
  57
  58     <para>With <command>machine-id</command>, the identifier of the current machine will be
  59     printed. See
  60     <citerefentry><refentrytitle>machine-id</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
  61     </para>
  62
  63     <para>With <command>boot-id</command>, the identifier of the current boot will be
  64     printed.</para>
  65
  66     <para>Both <command>machine-id</command> and <command>boot-id</command> may be combined
  67     with the <option>--app-specific=<replaceable>app-id</replaceable></option> switch to
  68     generate application-specific IDs. See
  69     <citerefentry><refentrytitle>sd_id128_get_machine</refentrytitle><manvolnum>3</manvolnum></citerefentry>
  70     for the discussion when this is useful.</para>
  71
  72     <para>With <command>invocation-id</command>, the identifier of the current service invocation
  73     will be printed. This is available in systemd services. See
  74     <citerefentry><refentrytitle>systemd.exec</refentrytitle><manvolnum>5</manvolnum></citerefentry>.
  75     </para>
  76
  77     <para>With <command>show</command>, well-known UUIDs are printed. When no arguments are specified, all
  78     known UUIDs are shown. When arguments are specified, they must be the names or values of one or more
  79     known UUIDs, which are then printed.</para>
  80   </refsect1>
  81
  82   <refsect1>
  83     <title>Options</title>
  84
  85     <para>The following options are understood:</para>
  86
  87     <variablelist>
  88       <varlistentry>
  89         <term><option>-p</option></term>
  90         <term><option>--pretty</option></term>
  91
  92         <listitem><para>Generate output as programming language snippets.</para></listitem>
  93       </varlistentry>
  94
  95       <varlistentry>
  96         <term><option>-a <replaceable>app-id</replaceable></option></term>
  97         <term><option>--app-specific=<replaceable>app-id</replaceable></option></term>
  98
  99         <listitem><para>With this option, an identifier that is the result of hashing the
 100         application identifier <replaceable>app-id</replaceable> and the machine identifier will be
 101         printed. The <replaceable>app-id</replaceable> argument must be a valid sd-id128 string
 102         identifying the application.</para>
 103         </listitem>
 104       </varlistentry>
 105
 106       <varlistentry>
 107         <term><option>-u</option></term>
 108         <term><option>--uuid</option></term>
 109
 110         <listitem><para>Generate output as an UUID formatted in the "canonical representation", with five
 111         groups of digits separated by hyphens. See the
 112         <ulink url="https://en.wikipedia.org/wiki/Universally_unique_identifier#Format">wikipedia</ulink>
 113         for more discussion.</para></listitem>
 114       </varlistentry>
 115
 116       <xi:include href="standard-options.xml" xpointer="help" />
 117       <xi:include href="standard-options.xml" xpointer="version" />
 118     </variablelist>
 119   </refsect1>
 120
 121   <refsect1>
 122     <title>Exit status</title>
 123
 124     <para>On success, 0 is returned, a non-zero failure code otherwise.</para>
 125   </refsect1>
 126
 127   <refsect1>
 128     <title>See Also</title>
 129     <para>
 130       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 131       <citerefentry><refentrytitle>sd-id128</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 132       <citerefentry><refentrytitle>sd_id128_get_machine</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 133     </para>
 134   </refsect1>
 135
 136 </refentry>