Change screen brightness in Linux

July 13, 2015

Your desktop environment should already have come bundled with some button for adjusting the screen brightness. The brightness adjusts the backlight intensity that illuminates the screen. I used the one that comes by default in Gnome 3 and I felt that my display was not bright enough. I thought I’ll tinker a bit from the command line. RandR is an extension to the X display server that allows such tinkering as and when necessary. Within most Linux distributions there is a small utility called xrandr which comes handy to interface with RandR.

Let’s find out the connected screens:

[email protected]:~> xrandr -q | grep connected
LVDS1 connected primary 1366x768+0+0 (normal left inverted right x axis y axis) 309mm x 173mm
DP1 disconnected (normal left inverted right x axis y axis)
HDMI1 disconnected (normal left inverted right x axis y axis)
VGA1 disconnected (normal left inverted right x axis y axis)
VIRTUAL1 disconnected (normal left inverted right x axis y axis)

As we note from the output LVDS1 is the only connected screen. To adjust its brightness we’ll shoot:
[email protected]:~> xrandr –output LVDS1 –brightness 0.8

1.0 being the max while 0.0 is a blackout. If you go above 1.0 display becomes weird.