Changing from text boot by default to gui boot with Rabian (Debian derivative)

This is for the Radxa Rock version of Debian.  Found by Debashis De (G+ id)

To help others:

    sudo systemctl set-default multi-user.target

To start GUI from text mode:

    sudo /etc/init.d/lightdm start

To go back to GUI mode:

    sudo systemctl set-default graphical.target

To get the current run-level:

    sudo systemctl get-default