I recently purchased a new laptop (an Asus VivoBook F200MA) for using as my main Linux box. Installing everything went smoothly except for one thing: adjusting the brightness didn’t work, neither via the normal keybindings or with xbacklight.

Using the screen with the brightness set at 100% is both battery-draining and eye-straining¹ so I really needed to get it fixed. I found a small application called light which worked right out of the box.

The commands are easy to remember too:

light -G               # Get brightness
light -S <percentage>  # Set brightness
light -A <percentage>  # Increase brightness
light -U <percentage>  # Decrease brightness