$xrandr | grep connected VGA-0 connected 1024x768+0+0 (normal left inverted right x axis y axis) 340mm x 270mm $xrandr --output VGA-0 --brightness 1 $xrandr --output VGA-0 --brightness 0.5 $ Theory Drop The X Resize, Rotate and Reflect Extension (RandR)[2] is an X Window System extension, which allows clients to dynamically change X screens, so as to resize, rotate and reflect the root window of a screen.
source:http://en.wikipedia.org/wiki/RandR