I first submitted this tutorial a couple of months ago over at http://linuxiso.org/forums as user adpsimpson.

Having spent ages wishing the hotkeys on my laptop would work, I spent most of an afternoon looking into it. Since no site I found explained it satisfactorily, here's my method...

The first step is to find out which of the keys are registered by the kernel, and what their keycodes are (the unique event number that they cause). To do this you need a program called xev, (in Mandrake this is part of X11R6-contrib, is installed by default in Slack, and should be easy to find for other distros). From the terminal, in a graphical interface, type xev to launch it, move the mouse over the new window and press the hotkeys. What appears in the terminal is something like



The "keycode" (in this case 64) is the important part. The next is to make the keycode actually do something when X registers it. For this you need to run xmodmap to modify the keyboard map. A small script in the ~/.kde/Autostart folder (or similar for other desktops) means this will be done each time KDE is stated. I wanted key 176 to increase the system volume, and 174 to decrease it, so the script reads


Don't forget to make this executable. Run this script, re-run xev and you should now see, for example, F22 or F21 in the even notification.

The final step is to make F21 or F22 (or whatever you called your keys) actually do something useful. You can do this using the existing shortcut options (if you wish it to start an application), or you can use the program xbindkeys, here - http://hocwp.free.fr/xbindkeys/xbindkeys.html . This program links key events to bash commands, very easily.

The script in the KDE Autostart folder can then be modified to launch xbindkeys when KDE is launched, and the file ~/.xbindkeysrc modified to link the key events to the desired bash commands. I used dcop (the inter-program communication process) to tell kmix (the default KDE mixer) to increase/decrease the master volume (channel 0) whenever the relevant keys were pressed. Below is the complete file ~/.kde/Autostart/keycodes (MUST be executable):



Hopefully this will help people make their keyboards more useful. If anyone has any further suggestions, or knows of obvious or important differences between desktop environments, please post them below. However it should be relatively distro/desktop independent.