I installed debian stretch yesterday. I installed fish shell . I change the default shell to fish by the followingsu chsh -s 'which fish'Then again enter the this commandsu chsh -s `which fish`Now after I restart the PC I encountered the following error while using susathish@localhost ~> suPassword: Cannot execute which fish: No such file or directory
debian 9 terminal cannot change to su
linux;debian;fish
(Since I'm unable to comment. So posting here)Change user to su$ su(Then enter password)Type# chsh [username]In your case:# chsh rootEnter login shell /usr/bin/fishThat's it. Logout and login again. Should work