Re: How bind "Super" key *all by itself* to a function?

[Rusi]

On Monday, January 19, 2015 at 2:38:06 PM UTC+5:30, Yuri Khan wrote:
> [Damn Gmail. Its Send button is too near the "show quote" button and
> too high-contrast.]
> 
> On Mon, Jan 19, 2015 at 1:35 PM, Rusi  wrote:
> 
> >> However, you can use XKB (in X) and/or loadkeys (in tty) to map the
> >> Windows key to produce a different keycode such as F13, and then bind
> >> that to any function you like.
> >
> > Do you have a simple howto on that? [XKB]
> > With xmodmap it was at least conceivable
> > Xkb is too much of a dragon
> >
> > eg Say I have a broken ~ key and I want to make F12 generate ~
> 
> Not quite qualifies as "simple" but not very complicated.
> 
> * Find the XKB data directory. [Normally, this is /usr/share/X11/xkb.]
> * In its "keycodes" subdirectory, create a file that is unlikely to be
> overwritten by a future version of XKB (e.g. by prefixing it with your
> initials). [Let's name it "rusi" for the sake of this example.]
> * In this file, paste the following:
> 
> ===
> xkb_keycodes "f12tilde" {
>     # remappings go here...
> };
> 
> # you can have multiple remapping sections
> # and activate any subset thereof, just add more
> # xkb_keycodes "some_name" {
> #   # ...
> # };
> ===
> 
> Each remapping takes the form: <KEYNAME> = KEYCODE;
> 
> Refer to the existing entries in the section "default xkb_keycodes
> "evdev"" for key names and codes.
> 
> For keyname, find the name of the key you want to generate. In your
> case, it's <TLDE>.
> 
> For keycode, find the numeric code of the key you want to remap. In
> your case, it's the code which is normally bound to <FK12>, namely,
> 96.
> 
> So:
> 
> ===
>     <TLDE> = 96;
> ===
> 
> * Now that you have a keycodes section of your own, make a
> corresponding option. In the rules/evdev file, find the following
> header:
> 
> ===
> ! option = keycodes
> ===
> 
> In that section, add something like:
> 
> ===
>   rusi:f12tilde = +rusi(f12tilde)
> ===
> 
> Here, the form on the right refers to the keycodes filename and
> section, and the name on the left specifies the option name.
> 
> * Next, you want your X server to pick up this option. You can do it
> system-wide or per-user; I'll describe the system-wide setup because I
> find it easier and less DE-specific.
> * In the /usr/share/X11/xorg.conf.d directory [or its equivalent on
> your system], create a uniquely named file [e.g.
> 11-rusi-keycodes.conf]:
> 
> ===
> Section "InputClass"
>     Identifier "Keyboard layouts"
>     Driver "evdev"
>     Option "XkbOptions" "rusi:f12tilde"
>     Option "AutoServerLayout" "on"
>     MatchIsKeyboard "on"
>     MatchDevicePath "/dev/input/event*"
> EndSection
> ===
> 
> In the XkbOptions line, refer to the option name you added to rules/evdev.
> 
> Next time you boot X or plug in a keyboard, it should use your customization.
> 
> You can check the current set of XKB options by executing the
> following command in a terminal emulator within an X session:
> 
> $ setxkbmap -query
> 
> ----

!WORKS!

So where does one get initiated into the school of black art?
ie how do I figure out what those incantations mean?

One of my problems is how to debug:
If some small thing goes wrong and it does not work... where to start looking?

> 
> Legend has it that there is a possibility of using xkbcomp(1) on a
> user-specific configuration file, but I never learned that;
> system-wide is good enough for me.
> 
> One caveat: whenever you update the package that contains the
> rules/evdev file, it may be overwritten and you might have to re-add
> your option line.