I disabled the shell of user root with the command
chuser shell=/bin/false root and now I cannot switch to root with
sudo su -. PermitRootLogin is disabled too, so I don’t know how could I reestablish the shell of the root user. Any advice?
Any other user around who has the permission to edit
/etc/passwd and could change the shell back to the original entry? Or any chance to boot the machine into single user mode, if need be with a rescue disk?