I just updated my ubuntu to 20.04.4 and noticed that emacs is no longer there. Other programs that I had downloaded prior to updating, like racket and ocaml, still work. Emacs however, is not working - the emacs command is not recognized. I see that I still have a /etc/emacs folder ($ whereis emacs told me that), so I am not sure why the command $ emacs is not recognized anymore.
I would be interested in knowing both how to fix this but also what caused it. I am using WSL2, if that is relevant.
Edit: if it is relevant, I have discovered that npm (which I installed with apt) and angular (which I installed with npm) are also claiming to be not installed (eg Command 'npm' not found, but can be installed with:). When I run $ whereis npm the response is npm: . When I run whereis ng, the response is ng: /usr/bin/ng.
Edit 2: I have corrected my post to say I was using 18.04, not 18. My mistake, I apologize. I did not know core 18 existed.