Ubuntu – How to switch between gnome-shell and unity without logging off

Honestly, I would just log out and log back in. Even if you got a script to switch you mid-session, there could potentially be some Unity code still in RAM that might conflict with whatever session you are in. Also, whenever I switch from logging out / in, the Adwaita theme becomes default for Unity.

It would honestly be screwy. May I ask why you would want to switch environments mid-session?

Install the package gnome-shell, then you get an additional session GNOME in the login screen:

• How do I install and use the latest version of GNOME?