This built-in function ensures that each username in
/etc/passwd is unique. It succeeds if that is the case and fails otherwise.
Duplicate user names in
/etc/passwd create problems since it is unclear which account’s privileges are being used.
adduser command will not let you create a duplicate username. Such a setup typically means that the system has been compromised, tools to handle user management are buggy or the
/etc/passwd file was manually edited.
Delete duplicate usernames or modify them to be different.
description: "This check makes sure that every username in /etc/passwd is unique."