Use Systemd Timer to change Gnome wallpaper

Intro

In my gnome desktop, I have a script that run at login to random a new wallpaper. I still want to change wallpaper every 30 minutes. So systemd timer is created to do the job.

Use a systemd timer

1. create directory at ~/.config/systemd/user

2. create wallpaper.service

[Unit]
Description=Random Wallpaper Script

[Service]
ExecStart=/path/to/script/random_wallpaper_gnome_v2.sh

when task is running, the random_wallpaper_gnome_v2.sh will be executed.

3. create wallpaper.timer

[Unit]
Description=Run wallpaper task every 30 minutes after start

[Timer]
OnActiveSec=30min
OnUnitActiveSec=30min

[Install]
WantedBy=timers.target

OnActiveSec will activate the task 30 minutes after timer is started.
OnUnitActiveSec will activate again in 30 minutes after task is finished.

4. Enable and start timer.

systemctl --user daemon-reload
systemctl --user enable wallpaper.timer
systemctl --user start wallpaper.timer