What command would you use to view a user's details on the system?

The command getent passwd username retrieves detailed information about a specified user from the system's databases, including user name, user ID (UID), group ID (GID), user home directory, and the user's shell. This command queries the /etc/passwd file or any configured name service (like NIS or LDAP) for the requested user, providing a comprehensive view of their details.

This approach is particularly effective because it respects the system's configured methods of user identification and retrieval. Unlike simply displaying the username (which would be the output of whoami), getent queries not just the local passwd file but can also reach out to network services if configured. This allows for consistency across systems in environments where user information is centrally managed.

The other methods mentioned do not serve the same purpose. For instance, whoami merely returns the current user's name and does not provide any detailed information about other users. The commands userinfo and userdetails do not exist as standard commands in typical Linux systems, meaning they wouldn't provide any output or information on user details.