> if you start it using the desktop GUI, systemd is not used, so I have to “ps aus | grep redshift“, copy the PID (or process name) and use kill or killall.
Or, since you started it with the GUI, you could just choose "quit" from the menu that appears when you click on it.
Or, since you started it with the GUI, you could just choose "quit" from the menu that appears when you click on it.