Image stolen from https://www.x.org

For some reason turning on your monitors in Linux is a bit funky, so you might need to type a few commands in the terminal for monitors to power off. I believe this method only works on x11.

To Turn Off:

xset -display :0.0 dpms force off

To Turn On:

xset -display :0.0 dpms force on

If your display turns off and then immediately back on then try the following which adds a delay of 1 second before turning the screen off. This give a chance for all events to be processed by the X server before turning the display off.

sleep 1 && xset -display :0.0 dpms force off

That’s pretty much all the commands you may need. If you need more info, check out this Ubuntu thread that talks about this.

https://askubuntu.com/questions/62858/turn-off-monitor-using-command-line/116806#116806