man/systemd.timer.xml

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   9   Copyright 2010 Lennart Poettering
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  24
  25 <refentry id="systemd.timer">
  26         <refentryinfo>
  27                 <title>systemd.timer</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.timer</refentrytitle>
  42                 <manvolnum>5</manvolnum>
  43         </refmeta>
  44
  45         <refnamediv>
  46                 <refname>systemd.timer</refname>
  47                 <refpurpose>systemd timer configuration files</refpurpose>
  48         </refnamediv>
  49
  50         <refsynopsisdiv>
  51                 <para><filename>systemd.timer</filename></para>
  52         </refsynopsisdiv>
  53
  54         <refsect1>
  55                 <title>Description</title>
  56
  57                 <para>A unit configuration file whose name ends in
  58                 <filename>.timer</filename> encodes information about
  59                 a timer controlled and supervised by systemd, for
  60                 timer-based activation.</para>
  61
  62                 <para>This man page lists the configuration options
  63                 specific to this unit type. See
  64                 <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
  65                 for the common options of all unit configuration
  66                 files. The common configuration items are configured
  67                 in the generic [Unit] and [Install] sections. The
  68                 timer specific configuration options are configured in
  69                 the [Timer] section.</para>
  70
  71                 <para>For each timer file a matching unit file must
  72                 exist, describing the unit to activate when the timer
  73                 elapses. By default a service by the same name as the
  74                 timer (except for the suffix) is activated. Example: a
  75                 timer file <filename>foo.timer</filename> activates a
  76                 matching service <filename>foo.service</filename>. The
  77                 unit to activate may be controlled by
  78                 <varname>Unit=</varname> (see below).</para>
  79         </refsect1>
  80
  81         <refsect1>
  82                 <title>Options</title>
  83
  84                 <para>Timer files must include a [Timer] section,
  85                 which carries information about the timer it
  86                 defines. The options specific to the [Timer] section
  87                 of timer units are the following:</para>
  88
  89                 <variablelist>
  90                         <varlistentry>
  91                                 <term><varname>OnActive=</varname></term>
  92                                 <term><varname>OnBootup=</varname></term>
  93                                 <term><varname>OnStartup=</varname></term>
  94                                 <term><varname>OnUnitActive=</varname></term>
  95                                 <term><varname>OnUnitInactive=</varname></term>
  96
  97                                 <listitem><para>Defines timers
  98                                 relative to different starting points:
  99                                 <varname>OnActive=</varname> defines a
 100                                 timer relative to the moment the timer
 101                                 itself is
 102                                 activated. <varname>OnBootup=</varname>
 103                                 defines a timer relative to when the
 104                                 machine was booted
 105                                 up. <varname>OnStartup=</varname>
 106                                 defines a timer relative to when
 107                                 systemd was
 108                                 started. <varname>OnUnitActive=</varname>
 109                                 defines a timer relative to when the
 110                                 unit the timer is activating was last
 111                                 activated. <varname>OnUnitInactive=</varname>
 112                                 defines a timer relative to when the
 113                                 unit the timer is activating was last
 114                                 deactivated.</para>
 115
 116                                 <para>Multiple directives may be
 117                                 combined, of the same and of different
 118                                 types. For example, by combining
 119                                 <varname>OnBoot=</varname> and
 120                                 <varname>OnUnitActive=</varname> it is
 121                                 possible to define a timer that
 122                                 elapses in regular intervals and
 123                                 activates a specific service each
 124                                 time.</para>
 125
 126                                 <para>The arguments to the directives
 127                                 are time spans configured in
 128                                 seconds. Example: "OnBoot=50" means
 129                                 50s after boot-up. The argument may
 130                                 also include time units. Example:
 131                                 "OnBoot=5h 30min" means 5 hours and 30
 132                                 minutes after boot-up. For details
 133                                 about the syntax of time spans see
 134                                 <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
 135
 136                                 <para>If a timer configured with
 137                                 <varname>OnBootup=</varname> or
 138                                 <varname>OnStartup=</varname> is
 139                                 already in the past when the timer
 140                                 unit is activated, it will immediately
 141                                 elapse and the configured unit is
 142                                 started. This is not the case for
 143                                 timers defined in the other
 144                                 directives.</para></listitem>
 145
 146                                 <para>These are monotonic timers,
 147                                 independant of wall-clock time and timezones. If the
 148                                 computer is temporarily suspended, the
 149                                 monotonic clock stops too.</para>
 150
 151                         </varlistentry>
 152                         <varlistentry>
 153                                 <term><varname>Unit=</varname></term>
 154
 155                                 <listitem><para>The unit to activate
 156                                 when this timer elapses. The argument is a
 157                                 unit name, whose suffix is not
 158                                 <filename>.timer</filename>. If not
 159                                 specified this value defaults to a
 160                                 service that has the same name as the
 161                                 timer unit, except for the
 162                                 suffix. (See above.) It is recommended
 163                                 that the unit name that is activated
 164                                 and the unit name of the timer unit
 165                                 is chosen identical except for the
 166                                 suffix.</para></listitem>
 167                         </varlistentry>
 168                 </variablelist>
 169         </refsect1>
 170
 171         <refsect1>
 172                   <title>See Also</title>
 173                   <para>
 174                           <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 175                           <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 176                           <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 177                           <citerefentry><refentrytitle>systemd.service</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 178                   </para>
 179         </refsect1>
 180
 181 </refentry>