I find it annoying not having a CTRL key available for both hands so I tend to swap the Command and CTRL key settings on my 2012 “Slackbook”.

1. Launch a terminal
2. Edit the X11 Keyboard Extension

# vim /usr/share/X11/xkb/symbols/pc

3. Make the following changes. Ensure your file looks like this:

key <LCTL> { [ Super_L ] }; key <LWIN> { [ Control_L ] }; ... key <RCTL> { [ Super_R ] }; key <RWIN> { [ Control_R ] };