Ubuntu – How to change brightness through terminal

11.04brightness

Now I can change it by Fn+ arrow right but now I need to do it via my shell script

• adding to what Michał Šrajer says in some cases the brightness may be controlled from /sys/class/backlight/acpi_video0/brightness as is the case with my dell vostro 3400 and my the brightness range is 0-15. You may have to look for other folder in /sys/class if the same path as mine doesnot exit.