Extra keyboard keys/Xorg

From ArchWiki
< Extra keyboard keys
Revision as of 00:43, 1 September 2012 by Roysc (talk | contribs) (Xmonad: clean)
Jump to navigation Jump to search

Template:Article summary start Template:Article summary text Template:Article summary heading Template:Article summary wiki Template:Article summary wiki Template:Article summary wiki Template:Article summary wiki Template:Article summary end

When we are in a graphical environment we may want a key to print a special character or execute a command. There are some ways of doing that and they are covered in this HOWTO.

Template:Box Note

Map keycodes to symbols


The most traditional and proficient way to make a key output a character when you are in X is to use xmodmap. Xmodmap is roughly the X equivalent of loadkeys: it reads a file containing some directives. As loadkeys, it can be used to modify many aspects of the behaviour of your keyboard (such as modifiers, etc.), but I will not cover these aspects in this article. The only kind of directive I am interested in here associates an X keycode to a keysym. xmodmap is included in the xorg-server-utils package.

# pacman -S xorg-server-utils

Step 1: Create the xmodmap file

In this file, you have to list the keycode directives, with the following syntax:

keycode <Xkeycode> = <keysym>

The list of X keysyms can be read in /usr/include/X11/keysymdef.h. Anyway, most of them are intuitive. Let us say that the X keycode of my hotkey is 239. If I want it to output a literal 'e', I will write the following directive:

keycode 239 = e

If I want it to output the symbol of the American currency, I will write the following directive:

keycode 239 = dollar

This can also be used to assign functions to multimedia keys. Special functions can be found in /usr/include/X11/XF86keysym.h.

An example ~/.Xmodmap:

keycode 160 = XF86AudioMute
keycode 176 = XF86AudioRaiseVolume
keycode 174 = XF86AudioLowerVolume

Multimedia programs such as Rhythmbox and Exaile are designed to work with keys assigned to XF86 Symbols out-of-the-box, without the need to configure a third-party application.

Step 2: Testing

Finally I have to source the file with xmodmap:

$ xmodmap ~/.Xmodmap

Step 3: Making it permanent

Obviously, this will work only for the current X session, use xprofile to make it permanent.

Map keycodes to actions

Using your Desktop Environment tools


Gnome Control Center is quite complete for the extra keyboard keys management. In fact it can directly detect scancodes which means that it can map any key seen by the kernel.


Keyboard shortcuts can be configured in System Settings -> Shortcuts and Gestures.


You can change the keyboard shortcuts in Keyboard Settings, which can be run using xfce4-keyboard-settings.


You can set keyboard shortcuts and actions in the keyboard section of your ~/.config/openbox/rc.xml file. For example, the following will lower the volume with a media key:

<keybind key="XF86AudioLowerVolume">
<action name="Execute">
<execute>amixer set Master 5- unmute</execute>

For more information, please visit urukrama's Openbox Guide or the Openbox Wiki.

You can use obkey utility from AUR for easy configuration.


Setting keys in PekWM is accomplished by editing your ~/.pekwm/keys file. For example, adding the following at the bottom of the Global section will lower the volume with a media key:

KeyPress = "XF86AudioLowerVolume" { Actions = "exec amixer set Master 5%- unmute &" }


If you use Xmonad as a stand alone window manager, you can edit the xmonad.hs to add unbound keyboard keys. You just need to find the Xf86 name of the key (such as XF86PowerDown) and look it up in /usr/include/X11/XF86keysym.h. It will give you a keycode (like 0x1008FF2A) which you can use to add a line like the following in the keybindings section of your xmonad.hs:

((0,               0x1008FF2A), spawn "sudo pm-suspend")


Open your ~/.i3/config and just bind the key (keysym or keycode) to a command:

bindsym XF86MonBrightnessDown  exec  xbacklight -dec 10
bindsym Print                  exec  scrot

Using third-party programs


KeyTouch is a program which allows you to easily configure the extra function keys of your keyboard. This means that you can define, for every individual function key, what to do if it is pressed.

See the detailed article: keytouch.

Using actkbd

From actkbd home page:

actkbd (available in AUR) is a simple daemon that binds actions to keyboard events. It recognises key combinations and can handle press, repeat and release events. Currently it only supports the linux-2.6 evdev interface. It uses a plain-text configuration file which contains all the bindings.

A sample configuration and guide is available here.

Using xbindkeys

xbindkeys (available in the extra repository) allows advanced mapping of keycodes to actions independently of the Desktop Environment.

A GUI called xbindkeys_config is available in AUR.