I tried installing FMRIB's FSL toolkit on Ubuntu 22.10. The downloaded fslinstaller.py runs absolutely fine without any errors, and clears both stages. It selects /usr/local/fsl as the default install directory. However, when trying to use FSL it is not detected. For instance, echo $FSLDIR returns nothing.I mean it literally returns an empty line. Anything else, including flirt -version and fsleyes simply returns a "not installed" message.

I couldn't find any record of this specific issue, so I figured asking here might help. If anybody has any ideas, you have my advanced gratitude.