Run script every 30 min with systemd

Question

I would like to execute a script every 30 min after booting into the system. I know you can use cron, but I don't plan to use this feature often therefore I'd like to try it with systemd.

So far I have only found the monotonic timers which allows to execute something once (at least I think so). How would the foo.timer and [email protected] look like in case I wanted to execute something every 30 minutes from boot/system start?

[email protected]

[Unit]
Description=run foo
Wants=foo.timer

[Service]
User=%I
Type=simple
ExecStart=/bin/bash /home/user/script.sh

foo.timer

[Unit]
Description=run foo

[Timer]
where I am stuck... ???

Answer 1

You need to create two files: one for service, other for timer with same name.

example:

/etc/systemd/system/test.service

[Unit]
Description=test job

[Service]
Type=oneshot
ExecStart=/bin/bash /tmp/1.sh

/etc/systemd/system/test.timer

[Unit]
Description=test

[Timer]
OnUnitActiveSec=10s
OnBootSec=10s

[Install]
WantedBy=timers.target

after that reload the systemd using command systemctl daemon-reload and start your timer by systemctl start test.timer, or enable it by default (systemctl enable test.timer).

test content of 1.sh

#!/bin/bash
echo `date` >> /tmp/2

And command to check all available timers: systemctl list-timers --all

More detailed info on project page and examples on ArchLinux page

Answer 2

Here is another option without using your timer. If timing is not terribly critical and and script isn't long running it will be fine for simple things.

[Unit]
Description=Run foo

[Service]
User=%I
Restart=always
RestartSec=1800s
ExecStart=/bin/bash /home/user/script.sh

Answer 3

The proper way is to use systemd-run you can schedule your job without the need to define your own unit.

It allows you to schedule by a calendar or every period of time. Assuming MYSELF is your full path application:

systemd-run --user --on-calendar '*:0/1' ${MYSELF} <args>