Trying to remap my left SUPER key (also called WINDOWS key) to left or right CONTROL key, with xkg
To change it temporarily, you can run this command:
setxkbmap -option altwin:ctrl_win
To change it persistently, open the /etc/default/keyboard file for editing, change the line
XKBOPTIONS=""
to
XKBOPTIONS="altwin:ctrl_win"
and reboot.