Xmodmap - how do I use ctrl as a modifier?

Question

Basic keyboard layout:

• 1 → 1
• Shift+1 → !

I would like: Ctrl+1 → ¹. (Superscript one character). The following code allows me to type ¹, but only with Shift+1:

xmodmap -e "keycode  10 = 1 onesuperior"

Conclusively, I would like to keep Shift+1 for ! and Ctrl+1 for ¹.

Answer 1

• This seems to me very related to:

  How do I assign a keyboard shortcut that uses AltGr as a modifier key?

  Keep Right Alt or AltGr as ISO_Level3_Shift and try to use it as Alt Modifier too.

  Where in your case is reverse: Keep Right Ctrl or Left Ctrl as Control Modifier and an extend it to be used a Level Shift.

• I couldn't get it to work in both functions, one trial was by adding actions: (Doesn't work)

  key <RCTL> {
           type= "ONE_LEVEL",
           symbols[Group1]= [ ISO_Level5_Shift ],
           actions[Group1]= [ SetMods(modifiers=Control) ]
  };
  

  from xkb - problems using virtual keys and ISO_Level3_Shift key but it just works one way only.

  Possibly, someone knowing XKB very well can make such setup.

• One setup that works for me: (no key repeat)

  1. Install and setup xbindkeys & xautomation as in How can I change what keys on my keyboard do? (How can I create custom keyboard commands/shortcuts?)

  2. Add this lines to ~/.xbindkeysrc

     "usleep 150000; xte 'keyup Control_L' 'str ¹' 'keydown Control_L'"
       m:0x4 + c:10
       control + 1
     

     For me, I have ¹ with AlgGr. So I could use this too:

     "usleep 150000; xte 'keyup Control_L' 'keydown ISO_Level3_Shift' 'key 1' 'keyup ISO_Level3_Shift' 'keydown Control_L'"
     

  3. Restart xbindkeys daemon

     pkill xbindkeys;xbindkeys
     

Answer 2

You can use xev command and then push Ctrl key, then see the keycode, for example mine is "keycode 37" for Ctrl.

However I didn't think superscript will work in editor nor terminal/console and anything except word processor. Superscript and subscript exist in word editor (LibreOffice, Ms Word, etc) but, for example, in Latex we use underscore "_" for subscript and ^ for superscript.