Alterar monitor principal no ubuntu

Para alterar o monitor principal do Ubuntu, Mint, etc... (O monitor com a barra)

#!/bin/bash
# Author: Andrew Martin
# Credit: http://ubuntuforums.org/showthread.php?t=1309247
echo "Enter the primary display from the following:" # prompt for the display
xrandr --prop | grep "[^dis]connected" | cut --delimiter=" " -f1 # query connected monitors

read choice # read the users's choice of monitor

xrandr --output $choice --primary