How can I switch my current session between Unity, Unity 2D, and Gnome?

If I am currently logged in to Unity, is there a way for me to switch my current session to Unity 2D or Gnome without logging out and in again? I know I can restart Unity by running unity --replace. Is there an equivalent command for Unity 2D or Gnome that I could run to switch to it? If I am currently running Unity 2D or Gnome, will unity --replace switch me back to Unity?

Solution 1:

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?