xrandr

$ xrandr
xrandr: Failed to get size of gamma for output default
Screen 0: minimum 640 x 480, current 1920 x 1080, maximum 1920 x 1080
default connected 1920x1080+0+0 0mm x 0mm
   1920x1080      0.00*
   1280x1024      0.00
   1280x960       0.00
   1024x768       0.00
   800x600        0.00
   640x480        0.00