To enable the Fn + F3 and Fn + F4 shortcuts to work under linux and really manipulate the backlight brighntess on your Asus G73 series notebook, follow theese simple steps:

1. Clone this repository to your home directory (or wherever you want to, I'll do this example for ~/ for simplicity)

    cd
    git clone git://github.com/ktoso/g73-keyboard-backlight-sh.git g73
   

2. Make sure all scripts are marked executable:

    cd g73
    chmod +x *.sh
   

3. Take a look at these scripts to make sure you trust them, why? Because they'll need root access, without asking for the password . Now we'll add these scripts to allow sudoto run them without asking for any password:

    su -c 'visudo' # or 'sudo visudo' if you're a sudoer (on ubuntu etc)
   

There just add the following lines at the end of this file (or similar, with the script names etc). Of course, replace ktoso and /home/ktoso/ with your username and your home directory.

    ## allow running keyboard backlight scripts
    ktoso ALL=(ALL) NOPASSWD:/home/ktoso/g73/*

4. Now all that's left is to setup the key bindings for the scripts. If you're on KDE4, just go to System Settings -> Shortcuts and Gestures -> Custom Shortcuts and edit -> import... the file ~/g73/g73_keyboard.khotkeys which contains ready keybindings for these scripts. Now you may use Fn + F3 to make the keyboard backlight shine less, and the Fn + F4 combination to make it shine more.

   If you're on a GNOME or other windowing system, please follow the usual steps for them to add some own keybinding. What you want to bind is simply calling the ~/g73/g73_light_up.sh and ~/g73/g73_light_down.sh scrips - easy :-)

I hereby release this script as Beerware. Just for fun I guess ;-) The text bellow is the full text of the license:

  "THE BEER-WARE LICENSE" (Revision 42):
  <konrad.malawski@project13.pl> wrote this file. As long as you retain this notice you
  can do whatever you want with this stuff. If we meet some day, and you think
  this stuff is worth it, you can buy me a beer in return.
  -- 
  Konrad Malawski

I'll be more than happy if you'd drop a comment here if you used this script by the way: http://www.blog.project13.pl/index.php/fun/1163/g73-keyboard-backlight-scripts-source-github/ :-)