How to make caps-lock an additional ctrl?

Question

How do I remap caps-lock to an additional ctrl?

I have tried to modify /etc/default/keyboard and reboot:

XKBOPTIONS="ctrl:nocaps"

After doing that, ctrl became caps-lock which I don't want.

Answer 1

From one of my previous answer, there is a few change:

1. Install gnome-tweak-tool

   sudo apt install gnome-tweak-tool
   

2. Start gnome-tweaks

   gnome-tweaks
   

3. Go to Keyboard & mouse -> Additional Layout Options (refered as Options supplémentaires d'agencement on my screenshot) -> CapsLock Behavior

4. Change CapsLock from Deleted to CapsLock is also Ctrl

4. Change CapsLock from Desativated to CapsLock is also Ctrl (refered as Verr. maj. est également Ctrl on my screenshot)

This is the GUI way, using gnome-tweak-tool, I don't know if it fits your goal