chiark / gitweb /
unit: trim cgroups when going down
[elogind.git] / man / systemd-notify.xml
1 <?xml version='1.0'?> <!--*-nxml-*-->
2 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
3         "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
4
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8   Copyright 2010 Lennart Poettering
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23
24 <refentry id="systemd-notify">
25
26         <refentryinfo>
27                 <title>systemd-notify</title>
28                 <productname>systemd</productname>
29
30                 <authorgroup>
31                         <author>
32                                 <contrib>Developer</contrib>
33                                 <firstname>Lennart</firstname>
34                                 <surname>Poettering</surname>
35                                 <email>lennart@poettering.net</email>
36                         </author>
37                 </authorgroup>
38         </refentryinfo>
39
40         <refmeta>
41                 <refentrytitle>systemd-notify</refentrytitle>
42                 <manvolnum>1</manvolnum>
43         </refmeta>
44
45         <refnamediv>
46                 <refname>systemd-notify</refname>
47                 <refpurpose>Notify init system about start-up completion and other daemon status changes</refpurpose>
48         </refnamediv>
49
50         <refsynopsisdiv>
51                 <cmdsynopsis>
52                         <command>systemd-notify <arg choice="opt" rep="repeat">OPTIONS</arg> <arg choice="opt" rep="repeat">VARIABLE=VALUE</arg></command>
53                 </cmdsynopsis>
54         </refsynopsisdiv>
55
56         <refsect1>
57                 <title>Description</title>
58
59                 <para><command>systemd-notify</command> may be
60                 called by daemon scripts to notify the init system
61                 about status changes. It can be used to send arbitrary
62                 information, encoded in an environment-block-like list
63                 of strings. Most importantly it can be used for
64                 start-up completion notification.</para>
65
66                 <para>This is mostly just a wrapper around
67                 <function>sd_notify()</function> and makes this
68                 functionality available to shell scripts. For details
69                 see
70                 <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para>
71
72                 <para>The command line may carry a list of
73                 environment variables to send as part of the status
74                 update.</para>
75
76                 <para>Note that systemd will refuse reception of
77                 status updates from this command unless
78                 <varname>NotifyAccess=all</varname> is set for the
79                 service unit this command is called from.</para>
80
81         </refsect1>
82
83         <refsect1>
84                 <title>Options</title>
85
86                 <para>The following options are understood:</para>
87
88                 <variablelist>
89                         <varlistentry>
90                                 <term><option>--h</option></term>
91                                 <term><option>--help</option></term>
92
93                                 <listitem><para>Prints a short help
94                                 text and exits.</para></listitem>
95                         </varlistentry>
96
97                         <varlistentry>
98                                 <term><option>--ready</option></term>
99
100                                 <listitem><para>Inform the init system
101                                 about service start-up
102                                 completion. This is equivalent to
103                                 <command>systemd-notify
104                                 READY=1</command>. For details about
105                                 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>--pid=</option></term>
111
112                                 <listitem><para>Inform the init system
113                                 about the main PID of the
114                                 daemon. Takes a PID as argument. If
115                                 the argument is omitted the PID of the
116                                 process that invoked
117                                 <command>systemd-notify</command> is
118                                 used. This is equivalent to
119                                 <command>systemd-notify
120                                 MAINPID=$PID</command>. For details
121                                 about the semantics of this option see
122                                 <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para></listitem>
123                         </varlistentry>
124
125                         <varlistentry>
126                                 <term><option>--status=</option></term>
127
128                                 <listitem><para>Send a free-form
129                                 status string for the daemon to the
130                                 init systemd. This option takes the
131                                 status string as argument. This is
132                                 equivalent to <command>systemd-notify
133                                 STATUS=...</command>. For details
134                                 about the semantics of this option see
135                                 <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para></listitem>
136                         </varlistentry>
137
138                         <varlistentry>
139                                 <term><option>--booted</option></term>
140
141                                 <listitem><para>Returns 0 if the
142                                 system was booted up with systemd,
143                                 non-zero otherwise. If this option is
144                                 passed no message is sent. This option
145                                 is hence unrelated to the other
146                                 options. For details about the
147                                 semantics of this option see
148                                 <citerefentry><refentrytitle>sd_booted</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para></listitem>
149                         </varlistentry>
150                 </variablelist>
151
152         </refsect1>
153
154         <refsect1>
155                 <title>Exit status</title>
156
157                 <para>On success 0 is returned, a non-zero failure
158                 code otherwise.</para>
159         </refsect1>
160
161         <refsect1>
162                 <title>Example</title>
163
164                 <example>
165                         <title>Start-up Notification and Status Updates</title>
166
167                         <para>A simple shell daemon that sends
168                         start-up notifications after having set up its
169                         communication channel. During runtime it sends
170                         further status updates to the init
171                         system:</para>
172
173                         <programlisting>#!/bin/bash
174
175 mkfifo /tmp/waldo
176 systemd-notify --ready --status="Waiting for data..."
177
178 while : ; do
179         read a &lt; /tmp/waldo
180         systemd-notify --status="Processing $a"
181
182         # Do something with $a ...
183
184         systemd-notify --status="Waiting for data..."
185 done</programlisting>
186                 </example>
187         </refsect1>
188
189         <refsect1>
190                 <title>See Also</title>
191                 <para>
192                         <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
193                         <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
194                         <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
195                         <citerefentry><refentrytitle>sd_notify</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
196                         <citerefentry><refentrytitle>sd_booted</refentrytitle><manvolnum>3</manvolnum></citerefentry>
197                 </para>
198         </refsect1>
199
200 </refentry>