Use setxkbmap to swap the Left Shift and Left Control

Question

Is it possible to swap the Left Shift and the Left CTRL keys using setxkbmap instead of xmodmap?

EDIT

I have switched to Fcitx, which works way much better with my keyboard layout and customized keymap than IBus in every respect. I highly recommend it.

Answer 1

xmodmap is obsolete; so indeed it should be done with the xkb tools.

The swap you want seems not to be included by default wth X11 files; so you have to write it yourself.

The page http://madduck.net/docs/extending-xkb/ helped me to understand and find a way to do it.

Create a file ~/.xkb/keymap/mykbd where you put the output of setxkbmap, it will be your base keyboard definition; eg:

setxkbmap -print > ~/.xkb/keymap/mykbd

then, create a symbols file to define your key swaping, put it for exemple in ~/.xkb/symbols/myswap

there, put the following lines:

partial modifier_keys
xkb_symbols "swap_l_shift_ctrl" {
    replace key <LCTL>  { [ Shift_L ] };
    replace key <LFSH> { [ Control_L ] };
};

then, edit the ~/.xkb/keymap/mykbd file, and change the xkb_symbols line to add "+myswap(swap_l_shift_ctrl)"

finally, you can load it with xkbcomp -I$HOME/.xkb ~/.xkb/keymap/mykbd $DISPLAY (you cannot use "~" for the -I parameter). It will probably sput a lot of warnings about undefined symbols for some rare keys, but you can ignore them (eg, redirect error to dave: 2> /dev/null).

if you want to be able to easily swap between a normal and your inversed ctrl/shift one; just create under ~/.xkb/keymap/ another file, without the extra "myswap" option, and load it with xkbcomp. You can make two small scripts to load them.