A little X utility to enable the use of ordinary keys as modifiers
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This is a quick hack and you should use xcape instead.


This little X utility enables the use of keys simultaneously as modifiers and ordinary keys,

The original key behavior is maintained under simple key press/release circumstances; but when a key is chorded, it can act as a modifier.

E.g.: left shift + b produces B, but left shift tapped on its own might produce parenleft.



make && make install

By default, this will install in /usr/local/bin. If you'd like it somewhere else, then copy the executables to your bin directory of choice.


kdlaunch honors a configuration file at ~/.keydoublerc.

This file contains both xmodmap configuration and keydouble configuration.

An example configuration file is provided at example/keydoublerc.

To write your own, use xev to discover the natural keycode fo the key you'd like to alter. Then pick an unused keycode (working backwards from 255 is recommended). In .keydoublerc's natart_pairs, add a pair NATURAL_KEYCODE:UNUSED_KEYCODE and then add two xmodmap commands: one mapping the natural keycode to the modifier of your choice, and the other mapping the unused keycode to the keysym you'd like to appear when you tap. You may also need to add the keysym to the appropriate modifier (i.e. add control = Control_L). See xmodmap's docs for details.

If you have a personal xmodmap configuration, copy it into this file, put it at ~/.xmodmaprc (or change the relevant path in kdlaunch).

Once you've tested (try kdlaunch) and you're satisfied, add

kdlaunch &

to ~/.xinitrc.

To kill keydouble run kdkill.


  • libxtst
  • xorg-xmodmap
  • dash


The default keycode (called natural) of the original key is mapped to the modifier keysym and the keycode generated by keydouble (called artificial) under isolated key press/release is mapped to the original keysym.

The mapping is done by xmodmap and the artificial keycode generation by keydouble.


Error! Option "-query" not recognized

Either upgrade your x utils, or (what may be easier) hardcode your keyboard layout in kdlaunch. There's a comment pointing out where to put it.

If needed (i.e. if you encounter record module errors), the record X module can be loaded with:

Section "Module"
    Load "record"

in /etc/X11/xorg.conf.