This program can be used by owners of a laptop with the Intel GMA 500 chipset to change their brightness. It only works when the psb_gfx driver (embedded in current kernels) is used. For Ubuntu (and derivative) users this means for version 12.04 and later.
The program should be called with a single argument representing the brightness that you want to have your monitor set to, as a percentage. Once called (and when it has sufficient rights, usually root) it will try to write the provided percentage value to the file "/sys/class/backlight/psb-bl/brightness", which should change the brightness of your monitor.
For efficient use you should put the compiled brightness binary in your path (for instance in /usr/bin/), change ownership to root and make it suid. This can be done by using the following commands:
user@box:~/src/psb_brightness$ gcc brightness.c -o brightness
user@box:~/src/psb_brightness$ sudo chown root:root brightness
user@box:~/src/psb_brightness$ sudo mv brightness /usr/bin/
user@box:~/src/psb_brightness$ sudo chmod u+s /usr/bin/brightness
This way any user can run the program with root rights without needing to sudo
or su. You can test the program by running something like
user@box:~$ brightness 30 after which the brightness should noticeably
change.
This little program was brought to you by Sakartu.