Remap a key combination to another combination, e. g. Super+Ctrl+Shift+J -> Ctrl+Shift+Left

Question

I want to implement an addition key layer, so that I can access non-alphanumeric keys without having to move my wrists.

I've been using Autokey for this purpose, but the experience was unsatisfactory: it had occasional lags and let original keystrokes slip into certain apps.

So I need a low-level solution.

Solution

Give a combination of xbindkeys and xvkbd a try. xbindkeys listens for the keys and sends the translation to xvkbd.

sudo apt-get install xbindkeys xvkbd
xbindkeys --defaults > ~/.xbindkeysrc

Open .xbindkeysrc in your favourite editor. I commented everything else out, but it's good to refer to if required.

To check it out, I tried mapping Ctrl+; to Ctrl+V

"xvkbd -xsendevent -text "\Cv""
   control + semicolon

I expect you're after something like this

"xvkbd -xsendevent -text "\C\S\[Left]""
  Super+Control+Shift+J

Save the file, then run xbindkeys.

In order to reload any configuration changes, I killed the xbindkeys process then restarted.

xbindkeys syntax

I worked out the key combination by using a GUI for xbindkeys

sudo apt-get install xbindkeys-config
xbindkeys-config

Once you run that, press Get Key for the combination to put into the second line of your .xbindkeysrc file.

xvkbd syntax

From the manual:

\r - Return
\t - Tab
\b - Backspace
\e - Escape
\d - Delete
\S - Shift (modify the next character; please note that modify with ``\S'' will be ignored in many cases. For example, ``a\Cb\ScD\CE'' will be interpreted as a, Control-b, c, Shift-D, and Control-Shift-E.)
\C - Control (modify the next character)
\A - Alt (modify the next character)
\M - Meta (modify the next character)
\[keysym] - the keysym keysym (e.g., \[Left]), which will be processed in the similar matter with other general characters
\{keysym} - the keysym keysym (e.g., \{Left}), which will be processed in more primitive matter and can also be used for modofier keys such as Control_L, Meta_L, etc.; also, \{+keysym} and \{+keysym} will simulate press and release of the key, respectively [Version 3.3]
\Ddigit - delay digit * 100 ms
\xvalue - move mouse pointer (use "+" or "-" for relative motion)
\yvalue - move mouse pointer (use "+" or "-" for relative motion)
\mdigit - simulate click of the specified mouse button

Love to hear how it works out and if the combination was fit for your purpose. It looks good as a keymapper, but not necessarily a macro runner.

Comments

[Amias]

you might have to create custom virtual input driver to do this which i would guess would be written in C

[lolmaus - Andrey Mikhaylov]

@Amias, can you please elaborate?

[Amias]

you could have a xinput driver that runs the normal keyboard driver but interprets the keystrokes before passing them on to xorg , this would give you complete control but would be a moderately complex couple of days work for a C programmer.

[lolmaus - Andrey Mikhaylov]

I need a specific example.

[David]

Clears throat ;)

[lolmaus - Andrey Mikhaylov]

Hey @MarkHewitt! Thank you so much for the detailed response! Unfortunately, this doesn't work for me very well: the original keypress keeps coming through, which ruins the whole thing.