ArchLinux - Brighten up

Even though we have sophisticated commands like xbrightness and xrandr, it is fun to learn this mundane way to vary screen brightness.

With root permissions, navigate to this location /sys/class/backlight.

You might have one out of intel_backlight (Intel graphics) or acpi_video0 (ATI graphics). Go into that directory.

$ ls /sys/class/backlight/intel_backlight
actual_brightness  brightness  max_brightness  subsystem  uevent
bl_power           device      power           type

Now, cat max_brightness and brightness files to find out the max and current values of brightness.

$ cat /sys/class/backlight/intel_backlight/max_brightness 
4882

$ cat /sys/class/backlight/intel_backlight/brightness 
400

Now, to change brightness, change the value in the brightness file. You cannot make it higher than the max_brightness.

$ echo 200 > /sys/class/backlight/intel_backlight/brightness 

There you go, mundane method to change screen brightness.

Cheers

Refer

1. https://wiki.archlinux.org/index.php/backlight