LFCS Certification User and Group Management 5

Question 1

What is the difference between a user's login shell being /bin/false versus /sbin/nologin?

Accepted Answer

/bin/false immediately exits silently; /sbin/nologin prints a message before exiting

Answer

/sbin/nologin prints a configurable 'account is not available' message before exiting, while /bin/false exits immediately with no output.

Question 2

Which command displays the groups a specific user belongs to, showing both primary and supplementary groups?

Accepted Answer

groups username

Answer

groups username lists all groups (primary and supplementary) for the specified user; id also works but groups is more concise for this purpose.

Question 3

An admin creates a user with 'useradd -M username'. What does -M do?

Accepted Answer

Skips creating the user's home directory

Answer

useradd -M (uppercase) explicitly instructs useradd NOT to create the home directory, even if the CREATE_HOME default is set to yes in /etc/login.defs.

Question 4

Where would you configure the range of UIDs automatically assigned to new regular users created with useradd?

Accepted Answer

/etc/login.defs

Answer

/etc/login.defs contains UID_MIN and UID_MAX parameters that define the range from which useradd selects UIDs for new regular users.

Question 5

A user reports they cannot run sudo. After verifying their account exists, what should you check first?

Accepted Answer

Whether they are a member of the sudo or wheel group

Answer

sudo access is typically granted by membership in the 'sudo' group (Debian/Ubuntu) or 'wheel' group (RHEL/CentOS), so group membership is the first thing to verify.

LFCS Certification Practice Test

LFCS Certification Practice Test

LFCS Certification User and Group Management 5