You "switched the shell to bash", but you don't say how. Did you just run bash as a subshell, or did you really change your shell using chsh? It sounds like the former, given the fact that it is still complaining that your shell is fish.
Try chsh -s /usr/bin/bash, then log out completely and log back in before trying the script again. If that works, then hopefully you can set your shell back to fish after that, and either:
- Just drop to a
bash subshell to run the FSL tools
- Examine the changes that the FSL installer makes to the
bash startup scripts such as (but not limited to) ~/.bashrc and ~/.bash_profile. Then replicate these in your ~/.config/fish/config.fish (or a ~/.config/fish/conf.d/fsl.fish)
If that doesn't work, then I'll be honest, it's going to be difficult for most any of us to help you further since FSL seems to be be very niche software with a non-free-as-in-speech license that requires you to sign up for marketing spam to even view the installation script. That's just not something most of us here on Ask Ubuntu are going to be willing to do. If I could do a quick look at the installation script, I might have more options for you to try if this one doesn't work.
If this doesn't work, I would recommend that you ask on the FSL mailing list that they link to on their front page. It appears to be fairly active, and I don't see that you've asked this question there at this point.
