LFCS User and Group Management Practice Test 5 — 15 Questions

Question 1

An administrator needs to create a user 'john' with a home directory in /data/home/john, a UID of 1500, and membership in the group 'developers' as a secondary group. The group 'developers' already exists. Which single command accomplishes this?

Accepted Answer

useradd -u 1500 -d /data/home/john -G developers john. Option B is correct: useradd -u -d -G all in one command. Option A uses usermod which requires the user to exist first. Option C uses adduser which is distribution-specific and may not support all flags. Option D is missing the secondary group flag.

Answer

adduser --uid 1500 --home /data/home/john --group developers john

Answer

useradd john; usermod -u 1500 -d /data/home/john -G developers john

Answer

useradd -u 1500 -d /data/home/john -g developers john

Question 2

A user 'alice' has a umask of 027 in her .bashrc, but the system administrator wants to enforce a umask of 007 for all users in the 'staff' group. Where should the administrator place the umask command to ensure it cannot be overridden by users?

Accepted Answer

In /etc/pam.d/common-session with pam_umask.so. Option C is correct: /etc/bash.bashrc is sourced before user files, but users can still override? Actually, the safest is to use /etc/profile.d/ with a script, but the question asks for a location that cannot be overridden? Typically, /etc/bash.bashrc is for all bash users, but users can still override in their .bashrc after it. The only way to enforce is to set umask in /etc/profile or /etc/bash.bashrc and also in /etc/skel/.bashrc, but users can still change. Actually, no shell-level enforcement is absolute; root can set it in a login script that runs after user scripts? But the question is tricky. I'll set the correct answer to a pam module: option D: using pam_umask.so in /etc/pam.d/common-session. That ensures it is applied regardless of shell configuration. So D is correct. Other options are overrideable.

Answer

/etc/bash.bashrc

Answer

/etc/skel/.bashrc

Answer

/etc/profile

Question 3

Which TWO commands can be used to display the group membership of a user? (Choose two.)

Accepted Answer

id -Gn username. Options B and D are correct. id -Gn shows all group names for a user. groups also shows all groups. groups <user> is also correct. Option A shows only primary group. Option C shows only groups where user is explicitly listed, missing primary if inherited. Option E shows group ID only.

Answer

cat /etc/passwd | grep username

Answer

id -g username

Answer

grep username /etc/group

Question 4

Which THREE of the following are valid methods to temporarily switch to a different user account without logging out entirely? (Choose three.)

Accepted Answer

sudo -u username -s. Options A, B, and D are correct. su - username starts a login shell as that user. sudo -u username -s launches a shell as that user. runuser is a command that runs a program as another user (used in scripts). Option C (newgrp) changes the group, not user. Option E (login) requires a full login.

Answer

newgrp groupname

Answer

login username

Question 5

Which TWO commands are used to modify user account attributes such as password age, expiration, or lock status? (Choose two.)

Accepted Answer

chage. Options A and D are correct. chage is used for password aging. usermod can lock/unlock accounts (-L/-U) and set account expiration (-e). Option B (passwd) is used to change password, but not to set expiration directly (though -x can set max days). Option C (chsh) changes shell. Option E (useradd) creates users, not modify existing.

Answer

useradd

Answer

chsh

Answer

passwd

Question 6

Refer to the exhibit. An administrator adds user 'frank' to the group 'projectx' by editing /etc/group directly and changing the line to 'projectx:x:500:carol,dave,frank'. After saving, the administrator runs 'groups frank' and sees only 'frank' in the output. Why does frank not appear in the group 'projectx'?

Accepted Answer

The user 'frank' is still logged into the same session; he must log out and log back in for the new group to be recognized.. Option D is correct. Direct editing requires the user to log out and log back in for the new group to take effect. Option A is wrong because the GID is fine. Option B is wrong because usermod wasn't used, but editing is valid if syntax is correct. Option C is wrong because groups command reads from current session's group list, not just /etc/group.

Answer

Editing /etc/group directly is not a valid method; 'usermod -aG' must be used instead.

Answer

The group 'projectx' has a GID conflict with another group.

Answer

The 'groups' command reads only from /etc/group and the change should appear immediately.

Question 7

Refer to the exhibit. The shadow entry for user 'carol' shows 18000 in the third field. What does the value 18000 represent?

Accepted Answer

The number of days since the password was last changed.. Option B is correct. The third field in /etc/shadow is the date of last password change (in days since epoch). 18000 corresponds to about April 2025 (as of 2025). Option A is the first field (last change). Option C is the minimum days field (fourth field, which is 0). Option D is the warning days field (seventh field, which is 7).

Answer

The number of days until the account expires.

Answer

The minimum number of days required between password changes.

Answer

The number of days before password expiration that the user is warned.

Question 8

Refer to the exhibit. What is the primary group ID of user 'charlie'?

Accepted Answer

1005 (the same as UID). Option B is correct. In /etc/passwd, the fourth field (after the second colon) is the primary group GID. Here it is 1005. Option A is the UID (third field). Option C is the GECOS field (fifth field). Option D is not directly listed.

Answer

1000

Answer

Charlie Brown

Answer

1005

Question 9

A system administrator needs to add a new user 'alice' with UID 1050 and a home directory at /home/alice. Which command should be used?

Accepted Answer

useradd -u 1050 -d /home/alice -m alice. Option A is correct because useradd -u sets UID, -d sets home directory, -m creates the home directory. Option B uses incorrect flags -U and -h. Option C uses --home but not --create-home. Option D uses --create-home but without -d, it defaults to /home/alice with UID 1050, but the home directory path is not explicitly set to /home/alice.

Answer

useradd -U 1050 -h /home/alice alice

Answer

useradd --uid 1050 --home /home/alice alice

Answer

useradd --create-home --skel /etc/skel -u 1050 alice

Question 10

After attempting to log in as user 'alice', the system rejects the password. The admin checks /etc/passwd and sees 'alice:x:1001:1001::/home/alice:/bin/bash'. The /etc/shadow shows 'alice:!!:18200:0:99999:7:::', indicating the account is locked. Which command will unlock the account?

Accepted Answer

usermod -U alice. Option B is correct because usermod -U unlocks the password. Option A (passwd -u) is available on some systems but not standard across all Linux distributions. Option C sets the password to expire immediately, which does not unlock. Option D shows password status only.

Answer

passwd -S alice

Answer

passwd -u alice

Answer

chage -d 0 alice

Question 11

Which command adds an existing user to a supplementary group without removing the user from other groups?

Accepted Answer

usermod -aG groupname username. Option A is correct because usermod -aG appends the user to the specified group while retaining existing supplementary group memberships.

Answer

groupmod -a username groupname

Answer

usermod -A groupname username

Answer

usermod -g groupname username

Question 12

A user must change their password at next login per security policy. The admin wants to expire the password immediately. Which command accomplishes this?

Accepted Answer

chage -d 0 username. Option B is correct because chage -d 0 sets the last password change date to the epoch, forcing a password change on next login.

Answer

passwd -f username

Answer

usermod -p '' username

Answer

chage -M 90 username

Question 13

After deleting user 'alice', the system administrator wants to also remove the home directory and mail spool. Which command should be used?

Accepted Answer

userdel -r alice. Option A is correct because userdel -r removes the home directory and mail spool (if owned by the user).

Answer

userdel -Z alice

Answer

userdel -f alice

Answer

userdel --remove alice

Question 14

Which file stores the encrypted password (or password hash) for user accounts?

Accepted Answer

/etc/shadow. Option B is correct. The /etc/shadow file contains the encrypted password and password aging information. The /etc/passwd file historically contained passwords but now uses 'x' placeholder.

Answer

/etc/group

Answer

/etc/passwd

Answer

/etc/gshadow

Question 15

An admin needs to change the primary group of user 'alice' from 'grp1' to 'grp2', but alice should still be a member of 'grp1' as a supplementary group. Which command accomplishes this?

Accepted Answer

usermod -g grp2 -aG grp1 alice. Option C is correct. usermod -g changes the primary group to grp2, and -aG grp1 adds grp1 as a supplementary group without removing other groups.

Answer

usermod -s /bin/bash alice

Answer

usermod -g grp2 alice

Answer

usermod -G grp2 alice