The best way to do that is probably to install Gnome Tweak Tool:
sudo apt-get install gnome-tweak-tool
- Open tweak-tool and click on the typing section in the left column.
- You should now see the line Caps Lock key behavior on the left.
- Choose Make Caps Lock an additionnal Ctrl key instead of Disabled in the drop down list and you should be good.
Besides the the setting panel does not take a lot of time to come up on my machine, so I have no idea what the problem is.
Enjoy your new Ctrl key!
ere's a way to do it without installing extra software:
setxkbmap -layout us -option ctrl:nocaps
To permanently change the behaviour:
['ctrl:nocaps'](or add it to any existing options)
or on the command line (Warning -- this overwrites your existing settings!):
gsettings set org.gnome.desktop.input-sources xkb-options "['ctrl:nocaps']"