monitor brightness adjustment in linux

Platform which I tested on:

• grml 2009.10 Release Codename Hello-Wien [2009-10-31]
• Debian GNU/Linux squeeze/sid
• Lenovo laptop G460

There is a file:

/proc/acpi/video/VGA/LCD/brightness

If you cat it, you will see something like:

levels:  0 10 20 30 40 50 60 70 80 90 100

current: 70

Assuming you want to change your monitor brightness to 60, you can do this (as root) by:

# echo "60" > /proc/acpi/video/VGA/LCD/brightness

And today is Friday the 13th, make sure you brighten your monitor!