Terminal closes immediately after trying to change shell script back to bash

Question

I was playing around with fish shell on my Ubuntu but wanted to switch back to bash. I tried running

chsh -s /bin/bash

but that didn't work, I got some error, which IIRC was regarding permissions, so I tried doing

sudo chsh -s /bin/bash 

That seemed to work and didn't show any errors. So I proceed to try logging out and logging back in to see the effects of this change. But from then on, every time I try opening the terminal, it would just immediately close.

Does anyone know what I did wrong?

Answer 1

Managed to solve this myself. Allow me to explain:

I went to virtual console with ctrl + alt + F1 then tried logging in there, but same issue happened, I was a quick message pop up and I was back to login stage in the virtual console. The message went by way too fast so but I managed to grab it my camera.

It turns out it was an error with fish shell: (not exactly sure if how I caused this error)

fish: relocation error: fish: symbol _ZNSt7__cxx1112basic_stringIwSt11char_traitsIwESaIwEE7reserveEm, version GLIBCXX_3.4.21 not defined in file libstdc++.so.6 with link time reference

So this told me that fish shell was still my default shell script sudo chsh -s /bin/bash did not do the trick for me. I was able to further confirm this by checking /etc/passwd and saw that my user still has /usr/bin/fish and fish was broken somehow which caused the terminal to immediately close. Finally found the root of the problem!

I then proceed to edit my passwd file by running bash from grub as root following instructions from here: https://unix.stackexchange.com/a/282141/212011 where I simply find the line with my username and changed /usr/bin/bash back to /bin/bash and then it was all good again!