xbacklight

adjust backlight brightness using RandR extension

TLDR

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]

SYNOPSIS

xbacklight [-help] [-display display] [-get] [-set percent] [-inc percent] [-dec percent]

DESCRIPTION

Xbacklight is used to adjust the backlight brightness where supported. It finds all outputs on the X server supporting backlight brightness control and changes them all in the same way.

-get: Print out the current backlight brightness of each output with such a control. The brightness is represented as a percentage of the maximum brightness supported.
-set percent: Sets each backlight brightness to the specified level.
-inc percent: Increases brightness by the specified amount.
-dec percent: Decreases brightness by the specified amount.
-help: Print out a summary of the usage and exit.
-time milliseconds: Length of time to spend fading the backlight between old and new value. Default is 200.
-steps number: Number of steps to take while fading. Default is 20.

AUTHORS

Keith Packard, Open Source Technology Center, Intel Corporation.