xbacklight

Utility to adjust backlight brightness using the RandR extension. More information: https://gitlab.freedesktop.org/xorg/app/xbacklight.

• Get the current screen brightness as a percentage:
  xbacklight
• Set the screen brightness to 40%:
  xbacklight -set {{40}}
• Increase current brightness by 25%:
  xbacklight -inc {{25}}
• Decrease current brightness by 75%:
  xbacklight -dec {{75}}
• Increase backlight to 100%, over 60 seconds (value given in ms), using 60 steps:
  xbacklight -set {{100}} -time {{60000}} -steps {{60}}