How to disable the root shell in Linux?

petulia3478

As root, change /bin/bash to /bin/nologin (for the root user) in /etc/passwd and save the file.

# /bin/vi /etc/passwd

root:x:0:0:root:/root:/bin/nologin

When a non-root user tries to su to root, the following message will appear:

$ su -
Password:
su: /bin/nologin: No such file or directory

Warning: this prevents access to the root account by any programme that uses a shell i.e. su, ssh. Programmes not using a shell i.e. mail, sudo, can still access the root account.