{{tag>[linux systemd time timers cron]}}
=====Systemd timers, example=====
Lets say we want to start ''/home/heather/screenshot.sh'' every day at 23:58, with the parameter 4.

  * Create a service file ''/etc/systemd/system/HeatherScreenshot.service'':<code>
[Unit]
Description=HeatherScreenshot

[Service]
User=heather
Type=simple
ExecStart=/home/heather/screenshot.sh 4
</code>
  * Create a timer file ''/etc/systemd/system/HeatherScreenshot.timer'':<code>
[Unit]
Description=Runs HeatherScreenshot

[Timer]
# DayOfWeek Year-Month-Day Hour:Minute:Second
OnCalendar=23:58:00
Unit=HeatherScreenshot.service

[Install]
WantedBy=multi-user.target
</code>
  * Test run the static service:<code>systemctl start HeatherScreenshot.service</code>
  * Start and enable the timer:<code>
systemctl daemon-reload # if you modified the files
systemctl start HeatherScreenshot.timer
systemctl enable HeatherScreenshot.timer</code>
  * Show timer status:<code>systemctl list-timers --all
NEXT                         LEFT          LAST                         PASSED       UNIT                         ACTIVATES
Fri 2016-12-30 22:47:15 CET  4h 35min left Thu 2016-12-29 22:47:15 CET  19h ago      systemd-tmpfiles-clean.timer systemd-tmpfiles-clean.service
Sat 2016-12-31 00:00:00 CET  5h 47min left Fri 2016-12-30 00:00:05 CET  18h ago      logrotate.timer              logrotate.service
Sat 2016-12-31 00:00:00 CET  5h 47min left Fri 2016-12-30 00:00:05 CET  18h ago      man-db.timer                 man-db.service
Sat 2016-12-31 00:00:00 CET  5h 47min left Fri 2016-12-30 00:00:05 CET  18h ago      shadow.timer                 shadow.service
Sat 2016-12-31 00:59:55 CET  6h left       Fri 2016-12-30 12:27:32 CET  5h 44min ago HeatherScreenshot.timer      HeatherScreenshot.service

5 timers listed.</code>
  * To disable a timer, first stop and than disable it:<code>
systemctl stop HeatherScreenshot.timer
systemctl disable HeatherScreenshot.timer
</code>