man/systemd-notify.xml

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  23
  24 <refentry id="systemd-notify"
  25     xmlns:xi="http://www.w3.org/2001/XInclude">
  26
  27   <refentryinfo>
  28     <title>systemd-notify</title>
  29     <productname>systemd</productname>
  30
  31     <authorgroup>
  32       <author>
  33         <contrib>Developer</contrib>
  34         <firstname>Lennart</firstname>
  35         <surname>Poettering</surname>
  36         <email>lennart@poettering.net</email>
  37       </author>
  38     </authorgroup>
  39   </refentryinfo>
  40
  41   <refmeta>
  42     <refentrytitle>systemd-notify</refentrytitle>
  43     <manvolnum>1</manvolnum>
  44   </refmeta>
  45
  46   <refnamediv>
  47     <refname>systemd-notify</refname>
  48     <refpurpose>Notify service manager about start-up completion and other daemon status changes</refpurpose>
  49   </refnamediv>
  50
  51   <refsynopsisdiv>
  52     <cmdsynopsis>
  53       <command>systemd-notify <arg choice="opt" rep="repeat">OPTIONS</arg> <arg choice="opt" rep="repeat">VARIABLE=VALUE</arg></command>
  54     </cmdsynopsis>
  55   </refsynopsisdiv>
  56
  57   <refsect1>
  58     <title>Description</title>
  59
  60     <para><command>systemd-notify</command> may be called by daemon
  61     scripts to notify the init system about status changes. It can be
  62     used to send arbitrary information, encoded in an
  63     environment-block-like list of strings. Most importantly, it can be
  64     used for start-up completion notification.</para>
  65
  66     <para>This is mostly just a wrapper around
  67     <function>sd_notify()</function> and makes this functionality
  68     available to shell scripts. For details see
  69     <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
  70     </para>
  71
  72     <para>The command line may carry a list of environment variables
  73     to send as part of the status update.</para>
  74
  75     <para>Note that systemd will refuse reception of status updates
  76     from this command unless <varname>NotifyAccess=all</varname> is
  77     set for the service unit this command is called from.</para>
  78
  79   </refsect1>
  80
  81   <refsect1>
  82     <title>Options</title>
  83
  84     <para>The following options are understood:</para>
  85
  86     <variablelist>
  87       <varlistentry>
  88         <term><option>--ready</option></term>
  89
  90         <listitem><para>Inform the init system about service start-up
  91         completion. This is equivalent to <command>systemd-notify
  92         READY=1</command>. For details about the semantics of this
  93         option see
  94         <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para></listitem>
  95       </varlistentry>
  96
  97       <varlistentry>
  98         <term><option>--pid=</option></term>
  99
 100         <listitem><para>Inform the init system about the main PID of
 101         the daemon. Takes a PID as argument. If the argument is
 102         omitted, the PID of the process that invoked
 103         <command>systemd-notify</command> is used. This is equivalent
 104         to <command>systemd-notify MAINPID=$PID</command>. For details
 105         about the semantics of this option see
 106         <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para></listitem>
 107       </varlistentry>
 108
 109       <varlistentry>
 110         <term><option>--status=</option></term>
 111
 112         <listitem><para>Send a free-form status string for the daemon
 113         to the init systemd. This option takes the status string as
 114         argument. This is equivalent to <command>systemd-notify
 115         STATUS=...</command>. For details about the semantics of this
 116         option see
 117         <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para></listitem>
 118       </varlistentry>
 119
 120       <varlistentry>
 121         <term><option>--booted</option></term>
 122
 123         <listitem><para>Returns 0 if the system was booted up with
 124         systemd, non-zero otherwise. If this option is passed, no
 125         message is sent. This option is hence unrelated to the other
 126         options. For details about the semantics of this option, see
 127         <citerefentry><refentrytitle>sd_booted</refentrytitle><manvolnum>3</manvolnum></citerefentry>. An
 128         alternate way to check for this state is to call
 129         <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>
 130         with the <command>is-system-running</command> command. It will
 131         return <literal>offline</literal> if the system was not booted
 132         with systemd.  </para></listitem>
 133       </varlistentry>
 134
 135       <xi:include href="standard-options.xml" xpointer="help" />
 136       <xi:include href="standard-options.xml" xpointer="version" />
 137     </variablelist>
 138
 139   </refsect1>
 140
 141   <refsect1>
 142     <title>Exit status</title>
 143
 144     <para>On success, 0 is returned, a non-zero failure code
 145     otherwise.</para>
 146   </refsect1>
 147
 148   <refsect1>
 149     <title>Example</title>
 150
 151     <example>
 152       <title>Start-up Notification and Status Updates</title>
 153
 154       <para>A simple shell daemon that sends start-up notifications
 155       after having set up its communication channel. During runtime it
 156       sends further status updates to the init system:</para>
 157
 158       <programlisting>#!/bin/bash
 159
 160 mkfifo /tmp/waldo
 161 systemd-notify --ready --status="Waiting for data..."
 162
 163 while : ; do
 164         read a &lt; /tmp/waldo
 165         systemd-notify --status="Processing $a"
 166
 167         # Do something with $a ...
 168
 169         systemd-notify --status="Waiting for data..."
 170 done</programlisting>
 171     </example>
 172   </refsect1>
 173
 174   <refsect1>
 175     <title>See Also</title>
 176     <para>
 177       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 178       <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 179       <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 180       <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 181       <citerefentry><refentrytitle>sd_booted</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 182     </para>
 183   </refsect1>
 184
 185 </refentry>