systemd/man/systemd-notify.xml

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<?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">
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<refentry id="systemd-notify"
xmlns:xi="http://www.w3.org/2001/XInclude">
<refentryinfo>
<title>systemd-notify</title>
<productname>systemd</productname>
<authorgroup>
<author>
<contrib>Developer</contrib>
<firstname>Lennart</firstname>
<surname>Poettering</surname>
<email>lennart@poettering.net</email>
</author>
</authorgroup>
</refentryinfo>
<refmeta>
<refentrytitle>systemd-notify</refentrytitle>
<manvolnum>1</manvolnum>
</refmeta>
<refnamediv>
<refname>systemd-notify</refname>
<refpurpose>Notify service manager about start-up completion and other daemon status changes</refpurpose>
</refnamediv>
<refsynopsisdiv>
<cmdsynopsis>
<command>systemd-notify <arg choice="opt" rep="repeat">OPTIONS</arg> <arg choice="opt" rep="repeat">VARIABLE=VALUE</arg></command>
</cmdsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
<para><command>systemd-notify</command> may be called by daemon
scripts to notify the init system about status changes. It can be
used to send arbitrary information, encoded in an
environment-block-like list of strings. Most importantly, it can be
used for start-up completion notification.</para>
<para>This is mostly just a wrapper around
<function>sd_notify()</function> and makes this functionality
available to shell scripts. For details see
<citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
</para>
<para>The command line may carry a list of environment variables
to send as part of the status update.</para>
<para>Note that systemd will refuse reception of status updates
from this command unless <varname>NotifyAccess=all</varname> is
set for the service unit this command is called from.</para>
</refsect1>
<refsect1>
<title>Options</title>
<para>The following options are understood:</para>
<variablelist>
<varlistentry>
<term><option>--ready</option></term>
<listitem><para>Inform the init system about service start-up
completion. This is equivalent to <command>systemd-notify
READY=1</command>. For details about the semantics of this
option see
<citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>--pid=</option></term>
<listitem><para>Inform the init system about the main PID of
the daemon. Takes a PID as argument. If the argument is
omitted, the PID of the process that invoked
<command>systemd-notify</command> is used. This is equivalent
to <command>systemd-notify MAINPID=$PID</command>. For details
about the semantics of this option see
<citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>--status=</option></term>
<listitem><para>Send a free-form status string for the daemon
to the init systemd. This option takes the status string as
argument. This is equivalent to <command>systemd-notify
STATUS=...</command>. For details about the semantics of this
option see
<citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>--booted</option></term>
<listitem><para>Returns 0 if the system was booted up with
systemd, non-zero otherwise. If this option is passed, no
message is sent. This option is hence unrelated to the other
options. For details about the semantics of this option, see
<citerefentry><refentrytitle>sd_booted</refentrytitle><manvolnum>3</manvolnum></citerefentry>. An
alternate way to check for this state is to call
<citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>
with the <command>is-system-running</command> command. It will
return <literal>offline</literal> if the system was not booted
with systemd. </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>Example</title>
<example>
<title>Start-up Notification and Status Updates</title>
<para>A simple shell daemon that sends start-up notifications
after having set up its communication channel. During runtime it
sends further status updates to the init system:</para>
<programlisting>#!/bin/bash
mkfifo /tmp/waldo
systemd-notify --ready --status="Waiting for data..."
while : ; do
read a &lt; /tmp/waldo
systemd-notify --status="Processing $a"
# Do something with $a ...
systemd-notify --status="Waiting for data..."
done</programlisting>
</example>
</refsect1>
<refsect1>
<title>See Also</title>
<para>
<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd_booted</refentrytitle><manvolnum>3</manvolnum></citerefentry>
</para>
</refsect1>
</refentry>