lightweight X11 utility to dim the screen and/or keyboard backlight when idle
C Roff Makefile
Switch branches/tags
Clone or download
Fetching latest commit…
Cannot retrieve the latest commit at this time.
Failed to load latest commit information.

XDIMMER(1) - General Commands Manual


xdimmer - dim the screen and/or the keyboard backlight when idle or when ambient light changes


xdimmer [-a] [-d] [-k] [-n] [-p percent] [-s steps] [-t timeout]


xdimmer waits timeout number of seconds and if no keyboard or mouse input is detected, the screen backlight is dimmed to percent in steps steps, unless the -n option was specified. Once keyboard or mouse input is detected, the screen backlight is restored to its previous brightness value.

On OpenBSD, if the -k option is used, the keyboard backlight is also dimmed to zero and restored upon movement via the wscons(4) interface.

Also on OpenBSD, if the -a option is used and an ambient light sensor device is located via sysctl(8), screen backlight (and keyboard backlight if -k is used) is dimmed or brightened based on lux readings.



Change backlights according to ambient light sensor lux readings. Currently only supported on OpenBSD.


Print debugging messages to stdout.


Affect the keyboard backlight as well as the screen backlight. Currently only supported on OpenBSD.


Do not adjust the screen backlight (can only be used if -k is used).

-p percent

Absolute brightness value to which the backlight is dimmed. The default is 10 percent.

-s steps

Number of steps to take while decrementing backlight. The default is 20 steps.

-t timeout

Number of seconds to wait without receiving input before dimming. The default is 120 seconds.


xdimmer was written by joshua stein <>.

OpenBSD 6.2 - September 21, 2017