XK0-006 Services and User Management — Timed 10 Questions

Question 1

A Linux administrator needs to add a new user account 'jdoe' with UID 1500, primary group 'developers', home directory /home/jdoe, and login shell /bin/bash. Which command will accomplish this?

Accepted Answer

useradd -u 1500 -g developers -d /home/jdoe -s /bin/bash jdoe. The useradd command is the standard low-level utility for creating new user accounts on Linux. Options -u, -g, -d, and -s respectively set the UID, primary group, home directory, and login shell. This command is available across all major Linux distributions and is the correct choice for non-interactive account creation.

Answer

adduser -u 1500 -g developers -d /home/jdoe -s /bin/bash jdoe

Answer

usermod -u 1500 -g developers -d /home/jdoe -s /bin/bash jdoe

Answer

passwd -u 1500 -g developers -d /home/jdoe -s /bin/bash jdoe

Question 2

A Linux administrator needs to create a new user account for a contractor who will start next month. The account must be locked until the contractor's start date, but it must have a valid home directory and default shell. Which sequence of commands best accomplishes this?

Accepted Answer

useradd -m -s /bin/bash contractor && passwd -l contractor. Creating a user with useradd -m ensures the home directory is created, and -s /bin/bash sets the default shell. Locking the password immediately with passwd -l prevents the contractor from logging in until the start date. This combination meets all stated requirements without relying on system defaults.

Answer

useradd -m -s /bin/bash contractor && usermod -L contractor

Answer

adduser contractor --disabled-password && usermod -s /bin/bash contractor

Answer

useradd contractor && passwd -l contractor

Question 3

A junior Linux administrator needs to add a new user account named 'dba' with a home directory '/home/dba' and the Bash shell. The account should be created with the next available UID, and a group with the same name should also be created. Which command should the administrator run?

Accepted Answer

useradd -m -s /bin/bash dba. The useradd command with -m and -s /bin/bash creates the account, home directory, and sets the shell. By default, a group with the same name is created when USERGROUPS_ENAB is enabled, so no separate groupadd is needed. This is the standard, non-interactive way to provision a user account on most Linux distributions.

Answer

usermod -m -s /bin/bash -U dba

Answer

adduser dba

Answer

groupadd dba && useradd -g dba -d /home/dba -s /bin/bash dba

Question 4

A user reports that they cannot run sudo commands. The administrator checks and finds the user is not in the sudoers file. Which command should the administrator use to add the user to the sudo group on a Debian-based system?

Accepted Answer

usermod -aG sudo username. The usermod -aG sudo username command adds the user to the sudo group while preserving existing group memberships. On Debian-based systems, members of the sudo group are granted sudo privileges by default. This is the standard method to grant sudo access.

Answer

gpasswd -a username sudo

Answer

adduser username sudo

Answer

usermod -G sudo username

Question 5

A user reports that they cannot run `sudo` commands and receive the error: `user is not in the sudoers file. This incident will be reported.` The administrator needs to grant this user full sudo privileges. Which command should the administrator use?

Accepted Answer

usermod -aG sudo username. The error indicates the user is not authorized to use sudo. On Debian-based systems, the standard way to grant full sudo privileges is to add the user to the `sudo` group, which is preconfigured in `/etc/sudoers`. Using `usermod -aG sudo username` appends the user to that group without altering other group memberships. Other options use incorrect group names, unsafe file editing, or invalid commands.

Answer

echo "username ALL=(ALL) ALL" >> /etc/sudoers

Answer

passwd -a username sudo

Answer

usermod -aG wheel username

Question 6

A Linux administrator is troubleshooting a service that fails to start. The service unit file contains the line `ExecStart=/usr/bin/myservice --config /etc/myservice.conf`. After modifying the configuration file, the administrator runs `systemctl daemon-reload` and then `systemctl restart myservice`. However, the service still uses the old configuration. Which command should the administrator run to ensure the new configuration is applied?

Accepted Answer

systemctl kill -s HUP myservice. Sending SIGHUP with `systemctl kill -s HUP myservice` can force the service to reload its configuration if it supports that signal. Since the administrator already restarted the service and it still uses old config, the service might require a signal to re-read files. Other options either don't apply changes or are not appropriate for this scenario.

Answer

systemctl edit myservice

Answer

systemctl reload myservice

Answer

systemctl restart myservice

Question 7

A Linux administrator is configuring a systemd timer to run a backup script daily. The administrator creates a timer unit `backup.timer` and a service unit `backup.service`. Which two directives are required in the timer unit to schedule the job to run every day at 2:00 AM? (Choose two.)

Accepted Answer

Unit=backup.service. To schedule a daily backup at 2:00 AM, the timer unit must include `OnCalendar` to define the schedule and `Unit` to specify the service to activate. Other directives like `Persistent` and `WantedBy` are useful for enabling and catch-up but are not required for the core scheduling functionality.

Answer

WantedBy=timers.target

Answer

Requires=backup.service

Answer

Persistent=true

Question 8

A Linux administrator needs a service to start automatically at boot and be manageable with systemctl. The unit file is currently stored at /etc/systemd/system/myapp.service. After running 'systemctl daemon-reload', the administrator runs 'systemctl enable myapp.service' and receives the error 'Failed to enable unit: Unit file myapp.service does not exist.' Which command should the administrator run to resolve this?

Accepted Answer

systemctl daemon-reload. After placing a new unit file in /etc/systemd/system, systemd must re-read its configuration before the unit becomes known. Although the administrator ran daemon-reload earlier, the unit file was likely added afterward, so systemd's cache is stale. Running systemctl daemon-reload again refreshes the manager's unit list, after which systemctl enable can create the symlink and the service will start at boot.

Answer

systemctl link /etc/systemd/system/myapp.service

Answer

systemctl reset-failed myapp.service

Answer

systemctl unmask myapp.service

Question 9

A Linux administrator needs to create a new user account `alice` with a home directory `/home/alice`, a specific shell `/bin/bash`, and an expiration date of `2025-12-31`. The administrator also wants to ensure that a group with the same name is created. Which two commands can be used to achieve this? (Choose two.)

Accepted Answer

useradd -m -s /bin/bash -e 2025-12-31 alice. Both `useradd` with appropriate options and `adduser` can create the user with the specified home directory, shell, expiration date, and automatically create a group with the same name. The `useradd` command uses `-m` for home, `-s` for shell, and `-e` for expiration. The `adduser` command provides equivalent functionality with more user-friendly option names. The other options either use incorrect flags, attempt to modify a non-existent user, or require multiple steps.

Answer

useradd -d /home/alice -s /bin/bash -f 2025-12-31 alice

Answer

usermod -m -d /home/alice -s /bin/bash -e 2025-12-31 alice

Answer

groupadd alice && useradd -g alice -m -s /bin/bash -e 2025-12-31 alice

Question 10

A Linux administrator needs to grant a developer named 'alex' the ability to run the command '/usr/sbin/reboot' as root without entering a password, but must not allow any other command. The system uses sudo. Which of the following is the correct way to configure this?

Accepted Answer

Add 'alex ALL=(ALL) NOPASSWD: /usr/sbin/reboot' to /etc/sudoers using visudo.. The correct configuration must allow alex to run only the specified command without a password. Using visudo to edit /etc/sudoers with the entry 'alex ALL=(ALL) NOPASSWD: /usr/sbin/reboot' achieves this. The NOPASSWD tag removes the password prompt, and the command path restricts execution to that single binary. Other options either omit NOPASSWD or use an incorrect command path, failing the requirement.

Answer

Add 'alex ALL=(ALL) /usr/sbin/reboot' to /etc/sudoers.d/alex using visudo -f /etc/sudoers.d/alex.

Answer

Add 'alex ALL=(ALL) /usr/sbin/reboot' to /etc/sudoers using visudo.

Answer

Add 'alex ALL=(root) NOPASSWD: /usr/sbin/reboot' to /etc/sudoers using visudo.