Backlight, Battery and GUI Management

Controlling Display Backlight

Find your backlight interface

ls /sys/class/backlight/

This will display available interfaces like intel_backlight, acpi_video0, or similar.

Adjust backlight brightness

For Intel backlight (where 0 means turn off):

sudo tee /sys/class/backlight/intel_backlight/brightness <<< 0

Battery Management

Check battery percentage

upower -i /org/freedesktop/UPower/devices/battery_BAT0 | grep percentage

GUI settings

Use the GUI to turn it on or off.

Display Manager Control

Check active display manager

If you're unsure which display manager is in use, check with:

ps aux | grep dm

Stop/Start Display Manager

For LightDM:

sudo service lightdm stop
sudo service lightdm start

Or for GDM3:

sudo service gdm3 stop
sudo service gdm3 start

Note: When your GUI is turned off (after stopping the display manager), you can still access the terminal:
- Press Ctrl+Alt+F2 through Ctrl+Alt+F6 to switch to a virtual console
- Log in with your username and password
- Restart the GUI with: sudo service lightdm start or sudo service gdm3 start (depending on your system)