Xbindkeys

Xbindkeys is a program that allows to bind commands to certain keys or key combinations on the keyboard. Xbindkeys works with multimedia keys and is independent of the window manager and desktop environment.

Installation

Install the xbindkeys package.

Configuration

Create a blank ~/.xbindkeysrc, or you can create a sample file (Note this includes some bindings such as Ctrl+f, which you may want to edit or remove):

$ xbindkeys -d > ~/.xbindkeysrc

Now you can either edit ~/.xbindkeysrc to set keybindings, or you can do that with the #GUI method.

Tip: xbindkeys reloads the configuration file if modified. Send a HUP signal to force reloading: killall -HUP xbindkeys. When a HUP signal is sent to xbindkeys, changes take effect only after moving the mouse (see xbindkeys(1)).

Audio control

Here is an example configuration file that binds Fn key combos on a laptop to pactl commands that adjust audio, such as sound volume and mute status. Note that pound (#) symbols can be used to create comments.

~/.xbindkeysrc

# Increase volume
"pactl set-sink-volume @DEFAULT_SINK@ +1000"
   XF86AudioRaiseVolume

# Decrease volume
"pactl set-sink-volume @DEFAULT_SINK@ -1000"
   XF86AudioLowerVolume

# Mute volume
"pactl set-sink-mute @DEFAULT_SINK@ toggle"
   XF86AudioMute

# Mute microphone
"pactl set-source-mute @DEFAULT_SOURCE@ toggle"
   XF86AudioMicMute

For alternative commands to control volume, see PulseAudio#Keyboard volume control or ALSA#Keyboard volume control.

Backlight control

Keybindings for backlight control can be defined using the XF86MonBrightnessUp and XF86MonBrightnessDown keys. See Backlight#Backlight utilities for the available backlight control utilities.

GUI method

For graphical configuration install the xbindkeys_config-gtk2^AUR package and run:

$ xbindkeys_config

Identifying keycodes

To find the keycodes for a particular key, enter the following command:

$ xbindkeys --key

or the following to grab multiple keys:

$ xbindkeys --multikey

A blank window will pop up. Press the key(s) to which you wish to assign a command and xbindkeys will output a handy snippet that can be entered into ~/.xbindkeysrc. For example, while the blank window is open, press Alt+o to get the following output (results may vary):

"(Scheme function)"
    m:0x8 + c:32
    Alt + o

The first line represents a command.
The second line contains the state (0x8) and keycode (32) as reported by the tool xev.
The third line contains the keysyms associated with the given keycodes.

To use this output, copy either one of the last two lines to ~/.xbindkeysrc and replace "(Scheme function)" with the command you wish to perform.

To identify mouse buttons, xev can be used, see [1].

Tip: If the multikey mode is used, press q to quit the window.

Note: xev is provided within the xorg-xev package, see xev(1) for more information.

Making changes permanent

Once you are done configuring your keys, edit your xprofile or xinitrc file (depending on your window manager) and place

xbindkeys

before the line that starts your window manager or DE.

Simulating multimedia keys

The XF86Audio* and other multimedia keys (see LQWiki:XF86 keyboard symbols) are pretty-much well-recognized by the major DEs. For keyboards without such keys, you can simulate their effect with other keys

# Decrease volume on pressing Super-minus
"pactl set-sink-volume 0 -1000"
   m:0x50 + c:20
   Mod2+Mod4 + minus

However, to actually call the keys themselves you can use tools like xdotool and xmacro^AUR. Unfortunately since you would already be holding down some modifier key (Super or Shift, for example), X will see the result as Super-XF86AudioLowerVolume which will not do anything useful. Here is a script based on xmacro and xmodmap from the xorg-xmodmap package for doing this[2].

#!/bin/sh
echo 'KeyStrRelease Super_L KeyStrRelease minus' | xmacroplay :0
xmodmap -e 'remove Mod4 = Super_L'
echo 'KeyStrPress XF86AudioLowerVolume KeyStrRelease XF86AudioLowerVolume' | xmacroplay :0
xmodmap -e 'add Mod4 = Super_L'

This works for calling XF86AudioLowerVolume once (assuming you are using Super+minus), but repeatedly calling it without releasing the Super key (like tapping on a volume button) does not work. If you would like it to work that way, add the following line to the bottom of the script.

echo 'KeyStrPress Super_L' | xmacroplay :0

With this modified script, if you press the key combination fast enough your Super_L key will remain 'on' till the next time you hit it, which may result in some interesting side-effects. Just tap it again to remove that state, or use the original script if you want things to 'just work' and do not mind not multi-tapping on volume up/down.

These instructions are valid for pretty much any one of the XF86 multimedia keys (important ones would be XF86AudioRaiseVolume, XF86AudioLowerVolume, XF86AudioPlay, XF86AudioPrev, XF86AudioNext).

Mouse Chording

By dedicating one button on the mouse as a "chording" key (much like the Shift key on a keyboard), it is possible to use xbindkeys to configure your mouse to perform more actions than would otherwise be possible. This requires the use of Scheme, rather than the simplified xbindkeys syntax.

.xbindkeysrc.scm

(define (define-mouse-chords chord-key . definitions)
  (define (start-mouse-chord)
    (let ((cmd #f))
      (for-each
        (lambda (definition)
          (let ((key (list-ref definition 0)) (binding (list-ref definition 1)))
            (xbindkey-function key (lambda () (set! cmd binding)))))
        definitions)
      (xbindkey-function `(release ,chord-key)
        (lambda ()
          (remove-xbindkey `(release ,chord-key))
          (for-each
            (lambda (definition)
              (let ((key (list-ref definition 0)))
                (remove-xbindkey key)))
            definitions)
          (if cmd
            (begin
              (run-command cmd)
              (set! cmd #f))
          )))))
  (xbindkey-function chord-key start-mouse-chord))

With this function defined, you can now configure some chorded commands:

(define-mouse-chords "b:10"
  (list '(release "b:1") "xdotool click 8")
  (list '(release "b:2") "xdotool click 9")
)

This defines "button 10" as as chording key on your mouse. When button 10 is pressed down, the function will create bindings for the buttons defined inside the block. When button 10 is released, those bindings will be removed. So for example: with button 10 held down, pressing and releasing button 1, and then releasing button 10, will result in a virtual "button 8" (back) event being generated.

Troubleshooting

If, for any reason, a hotkey you already set in ~/.xbindkeysrc does not work, open up a terminal and type the following:

$ xbindkeys -n

By pressing the non-working key, you will be able to see any error xbindkeys encounter (e.g: mistyped command/keycode,...).

If the command for a keybind works via the xdotool in command line, but not when activated by the hotkey try adding "+ Release" to the hotkey (especially notable on GNOME):

"xdotool key --clearmodifiers XF86AudioPlay"
    Mod2 + F7 + Release

This will make the F7 key play/pause audio. Where the "xdotool" command would work in commandline, if the "+ Release" is removed it will fail with xbindkeys.

Note: Be aware that setting two or more keyboard layouts with e.g. setxkbmap -layout ch,dk results in different button states for the different layouts and xbindkeys will not be able to handle that.