Patrick L Archibald - Tech Blog -     About

Power Off Monitor When Locking Screen

Out of the box KDE Kubuntu 18.04 was not turning off the monitor when I locked the screen. I added a Bash script powerOffMonitor.sh in the run command field of the Event Notifications and Actions dialog box of the KDE System Settings.

System Settings screenshot

The powerOffMonitor.sh script contains two commands. A sleep for 5 seconds and then the xset to power off the monitor.

#!/bin/bash
#
# Power off monitor
#
/bin/sleep 5
/usr/bin/xset dpms force off

Gleaned from AskUbuntu.com.