NAME

       systemd.timer - Timer unit configuration

SYNOPSIS

       timer.timer

DESCRIPTION

       A unit configuration file whose name ends in .timer encodes information about a timer
       controlled and supervised by systemd, for timer-based activation.

       This man page lists the configuration options specific to this unit type. See
       systemd.unit(5) for the common options of all unit configuration files. The common
       configuration items are configured in the generic [Unit] and [Install] sections. The timer
       specific configuration options are configured in the [Timer] section.

       For each timer file, a matching unit file must exist, describing the unit to activate when
       the timer elapses. By default, a service by the same name as the timer (except for the
       suffix) is activated. Example: a timer file foo.timer activates a matching service
       foo.service. The unit to activate may be controlled by Unit= (see below).

       Unless DefaultDependencies= is set to false, timer units will implicitly have dependencies
       of type Conflicts= and Before= on shutdown.target. These ensure that timer units are
       stopped cleanly prior to system shutdown. Only timer units involved with early boot or
       late system shutdown should disable this option.

OPTIONS

       Timer files must include a [Timer] section, which carries information about the timer it
       defines. The options specific to the [Timer] section of timer units are the following:

       OnActiveSec=, OnBootSec=, OnStartupSec=, OnUnitActiveSec=, OnUnitInactiveSec=
           Defines monotonic timers relative to different starting points: OnActiveSec= defines a
           timer relative to the moment the timer itself is activated.  OnBootSec= defines a
           timer relative to when the machine was booted up.  OnStartupSec= defines a timer
           relative to when systemd was first started.  OnUnitActiveSec= defines a timer relative
           to when the unit the timer is activating was last activated.  OnUnitInactiveSec=
           defines a timer relative to when the unit the timer is activating was last
           deactivated.

           Multiple directives may be combined of the same and of different types. For example,
           by combining OnBootSec= and OnUnitActiveSec= it is possible to define a timer that
           elapses in regular intervals and activates a specific service each time.

           The arguments to the directives are time spans configured in seconds. Example:
           "OnBootSec=50" means 50s after boot-up. The argument may also include time units.
           Example: "OnBootSec=5h 30min" means 5 hours and 30 minutes after boot-up. For details
           about the syntax of time spans see systemd.unit(5).

           If a timer configured with OnBootSec= or OnStartupSec= is already in the past when the
           timer unit is activated, it will immediately elapse and the configured unit is
           started. This is not the case for timers defined in the other directives.

           These are monotonic timers, independent of wall-clock time and timezones. If the
           computer is temporarily suspended, the monotonic clock stops too.

           If the empty string is assigned to any of these options the list of timers is reset,
           and all prior assignments will have no effect.

       OnCalendar=
           Defines realtime (i.e. wallclock) timers via calendar event expressions. See
           systemd.time(7) for more information on the syntax of calendar event expressions.
           Otherwise the semantics are similar to OnActiveSec= and related settings.

       Unit=
           The unit to activate when this timer elapses. The argument is a unit name, whose
           suffix is not .timer. If not specified, this value defaults to a service that has the
           same name as the timer unit, except for the suffix. (See above.) It is recommended
           that the unit name that is activated and the unit name of the timer unit are named
           identically, except for the suffix.

SEE ALSO

       systemd(1), systemctl(8), systemd.unit(5), systemd.service(5), systemd.time(7),
       systemd.directives(7)