Systemd/timers: Difference between revisions

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Add section about systemd.services.<name>.startAt
https://man.archlinux.org/man/systemd.timer.5.en "services with RemainAfterExit=yes set (which stay around continuously even after the service's main process exited) are usually not suitable for activation via repetitive timers, as they will only be activated once, and then stay around forever."
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The following example timer runs a systemd unit every 5 minutes which invokes a bash script.
The following example timer runs a systemd unit every 5 minutes which invokes a bash script.
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systemd.timers."hello-world" = {
systemd.timers."hello-world" = {
   wantedBy = [ "timers.target" ];
   wantedBy = [ "timers.target" ];
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       OnBootSec = "5m";
       OnBootSec = "5m";
       OnUnitActiveSec = "5m";
       OnUnitActiveSec = "5m";
      # Alternatively, if you prefer to specify an exact timestamp
      # like one does in cron, you can use the `OnCalendar` option
      # to specify a calendar event expression.
      # Run every Monday at 10:00 AM in the Asia/Kolkata timezone.
      #OnCalendar = "Mon *-*-* 10:00:00 Asia/Kolkata";
       Unit = "hello-world.service";
       Unit = "hello-world.service";
     };
     };
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   };
   };
};
};
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in your terminal.
in your terminal.
==== Verifying your timestamp for systemd.time ====
If you do not understand the format that [https://www.freedesktop.org/software/systemd/man/latest/systemd.time.html systemd.time] expects, you can use the <code>systemd-analyze</code>'s <code>calendar</code> sub-command to understand the next ''N'' times when the timer will get triggered. Following is an example:<syntaxhighlight lang="shell-session">
$ systemd-analyze calendar --iterations=5 "10:00:00"
  Original form: 10:00:00
Normalized form: *-*-* 10:00:00
    Next elapse: Sat 2024-12-07 10:00:00 IST
      (in UTC): Sat 2024-12-07 04:30:00 UTC
      From now: 33min left
  Iteration #2: Sun 2024-12-08 10:00:00 IST
      (in UTC): Sun 2024-12-08 04:30:00 UTC
      From now: 24h left
  Iteration #3: Mon 2024-12-09 10:00:00 IST
      (in UTC): Mon 2024-12-09 04:30:00 UTC
      From now: 2 days left
  Iteration #4: Tue 2024-12-10 10:00:00 IST
      (in UTC): Tue 2024-12-10 04:30:00 UTC
      From now: 3 days left
  Iteration #5: Wed 2024-12-11 10:00:00 IST
      (in UTC): Wed 2024-12-11 04:30:00 UTC
      From now: 4 days left
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====Using the <code>systemd.services.&lt;name&gt;.startAt</code> shorthand====
====Using the <code>systemd.services.&lt;name&gt;.startAt</code> shorthand====