LFCS Certification User and Group Management 4

Question 1

Which command changes the primary group of an existing user to 'staff'?

Accepted Answer

usermod -g staff username

Answer

usermod -g (lowercase) sets the primary group, while -G (uppercase) sets supplementary groups, so -g staff is correct for changing the primary group.

Question 2

A user 'alice' has UID 1005. After deleting her account with userdel, a new user 'bob' is created and happens to receive UID 1005. What risk does this create?

Accepted Answer

Bob will own files previously owned by Alice that were not reassigned

Answer

Files on disk store the numeric UID, not the username, so any files Alice owned that weren't removed or reassigned will now appear owned by Bob.

Question 3

Which file must be edited to set a system-wide default umask for all users?

Accepted Answer

/etc/profile

Answer

/etc/profile is sourced by login shells for all users and is the standard place to set a system-wide default umask.

Question 4

What does the GECOS field (field 5) in /etc/passwd typically store?

Accepted Answer

Human-readable information like the user's full name and contact details

Answer

The GECOS field stores optional descriptive information about the user, conventionally the full name, office, phone number, and other details, used by commands like finger.

Question 5

How do you add an existing user 'jane' to the supplementary group 'developers' without removing her from other groups?

Accepted Answer

usermod -aG developers jane

Answer

The -a (append) flag combined with -G ensures jane is added to 'developers' without overwriting her existing supplementary group memberships.

LFCS Certification Practice Test

LFCS Certification Practice Test

LFCS Certification User and Group Management 4