remove-shell

remove-shell shellname

shellname
    The name of the shell to remove from /etc/shells (e.g., /bin/bash).

The remove-shell command is a utility to remove the shell defined for a given username from the /etc/shells file. This is useful for hardening a system by restricting which shells are available for users to use, therefore minimizing the attack surface.

It takes a single argument, the name of the shell to remove. The utility then searches the /etc/shells file for lines matching the given shell. If a match is found, the line is removed from the file.

It is important to note that removing a shell using remove-shell does not prevent a user from using that shell if it is explicitly specified when creating or modifying their account, or if the user can otherwise execute it. It only prevents the shell from being a default or automatically assigned shell.

This command generally requires root privileges to modify the /etc/shells file.

This command only modifies /etc/shells. It does not affect existing user accounts or prevent users from executing the shell if they have permissions to do so. Also, if /etc/shells does not exist, then the command will fail.

While remove-shell can help restrict user shells, it's not a comprehensive security measure. Ensure proper user permissions and consider other security hardening techniques to further protect the system.

chsh(1), shells(5), usermod(8)