Users and Group Management Flashcards

What does the 'w' command show when run on a Linux system?

Answer: Who is logged in and what they are doing

The w command displays currently logged-in users, their terminals, login times, and the commands they are running.

A user's entry in /etc/shadow shows '!' before the password hash. What does this mean?

Answer: The account is locked

A '!' prefix on the password hash in /etc/shadow indicates the account is locked and cannot be used for password authentication.

Which command would you use to see the password aging information for a user?

Answer: chage -l username

chage -l displays the password aging details including last change date, expiry date, and inactivity period.

What is the effect of setting a user's shell to /sbin/nologin?

Answer: The user cannot log in interactively

/sbin/nologin prints a message and rejects interactive login attempts, commonly used for service accounts.

Which file format stores group name, GID, and member list on a Linux system?

Answer: /etc/group

/etc/group stores each group's name, password placeholder, GID, and comma-separated list of member usernames.

What happens when you run 'newgrp developers' in a terminal?

Answer: Starts a new shell with developers as the active primary group

newgrp spawns a new shell session where the specified group becomes the user's active primary group for that session.

Which useradd option specifies a comment (typically the user's full name) for the account?

Answer: -c

The -c option sets the GECOS comment field in /etc/passwd, which traditionally stores the user's full name.