Difference between revisions of "Extra keyboard keys/Xorg"

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== Map keycodes to symbols ==
== Map keycodes to symbols ==
{{Merge|Xmodmap|This section describes only ''xmodmap'' utility, so it should be merged into the main article.}}
=== Introduction ===
=== Introduction ===

Revision as of 18:28, 5 October 2013

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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.

Note: This article assumes that your keys already have keycodes and that you know these codes, if not, see the Extra Keyboard Keys article where it is explained.

Map keycodes to symbols

Merge-arrows-2.pngThis article or section is a candidate for merging with Xmodmap.Merge-arrows-2.png

Notes: This section describes only xmodmap utility, so it should be merged into the main article. (Discuss in Talk:Extra keyboard keys/Xorg#)


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 in the Official Repositories.

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

Merge-arrows-2.pngThis article or section is a candidate for merging with Keyboard Shortcuts#X11_2.Merge-arrows-2.png

Notes: same topic (Discuss in Talk:Extra keyboard keys/Xorg#)

Tango-inaccurate.pngThe factual accuracy of this article or section is disputed.Tango-inaccurate.png

Reason: keycodes are mapped to keysyms and then keysyms can be mapped to actions (Discuss in Talk:Extra keyboard keys/Xorg#)

There are multiple ways to do that:

  • The most portable way using low level tools, such as acpid. Not all keys are supported, but configuration in uniform way is possible for keyboard keys, power adapter connection and even headphone jack (un)plugging events.
  • The universal way using Xorg utilities (e.g. Xbindkeys) and eventually your desktop environment or window manager tools.
  • The quicker way using a third-party program to do everything in GUI, such as the Gnome Control Center or Keytouch.

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


A simple X hotkey daemon with a powerful and compact configuration syntax.

Available as sxhkd-gitAUR and sxhkdAUR in AUR.


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.


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.


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

A GUI called xbindkeys_configAUR is available in AUR.