Quiz Module 8 - Services and Daemons

Instructions

This quiz contains 30 multiple-choice questions to validate your understanding of Module 8.

Tip: Answer each question before revealing the answer. The answers are hidden just after each question.

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Question 1

Which command is used to manage systemd services on Ubuntu 24.04?

1. service

2. systemctl

3. initctl

4. servicectl

See explanation

Correct answer: systemctl

Explanation: systemctl is the main command to manage systemd services. Examples: systemctl start service, systemctl stop service, systemctl status service, systemctl enable service, systemctl restart service.

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Question 2

Which command is used to start a service?

1. systemctl run service

2. systemctl start service

3. systemctl activate service

4. systemctl on service

See explanation

Correct answer: systemctl start service

Explanation: sudo systemctl start service starts a service. Other commands: stop (stop), restart (restart), reload (reload config), status (view status).

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Question 3

Which command is used to enable a service at startup?

1. systemctl start service

2. systemctl enable service

3. systemctl activate service

4. systemctl autostart service

See explanation

Correct answer: systemctl enable service

Explanation: sudo systemctl enable service enables a service at startup (creates a symbolic link). systemctl disable service disables. systemctl is-enabled service checks if enabled.

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Question 4

Which command is used to view the status of a service?

1. systemctl show service

2. systemctl status service

3. systemctl info service

4. systemctl view service

See explanation

Correct answer: systemctl status service

Explanation: systemctl status service displays the detailed status of a service: active/inactive, running, recent logs, etc. Very useful for diagnosing issues.

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Question 5

Where are the systemd service files located?

1. /etc/services

2. /etc/systemd/system/ or /lib/systemd/system/

3. /var/systemd/

4. /usr/services/

See explanation

Correct answer: /etc/systemd/system/ or /lib/systemd/system/

Explanation: The systemd .service files are in /lib/systemd/system/ (provided by packages) and /etc/systemd/system/ (custom, prioritized). After modification, run sudo systemctl daemon-reload.

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Question 6

Which command is used to view the logs of a service?

1. systemctl logs service

2. journalctl -u service

3. systemctl log service

4. service logs

See explanation

Correct answer: journalctl -u service

Explanation: journalctl -u service displays the logs of a specific service. Options: -f (follow in real-time), -n 50 (last 50 lines), --since today, --since "1 hour ago".

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Question 7

Which command reloads the systemd configuration after modifying a service file?

1. systemctl reload

2. systemctl daemon-reload

3. systemctl refresh

4. systemctl reload-config

See explanation

Correct answer: systemctl daemon-reload

Explanation: sudo systemctl daemon-reload reloads the systemd configuration after modifying a .service file. Necessary before starting/restarting a modified service. Do not confuse with systemctl reload service which reloads a running service's config.

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Question 8

Which directory contains the system cron jobs (for all users)?

1. /etc/cron

2. /etc/cron.d/

3. /var/cron/

4. /usr/cron/

See explanation

Correct answer: /etc/cron.d/

Explanation: /etc/cron.d/ contains the system crontab files (for all users). Similar format to user crontab but with a user field. Files must have correct permissions (no execution).

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Question 9

What is anacron?

1. A type of cron

2. A system that executes periodic tasks even if the system was off

3. A monitoring tool

4. A systemd service

See explanation

Correct answer: A system that executes periodic tasks even if the system was off

Explanation: anacron executes tasks from /etc/cron.daily/, /etc/cron.weekly/, /etc/cron.monthly/ even if the system was off at the scheduled time. Useful for systems that are not always on.

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Question 10

What is the modern alternative to cron with systemd?

1. systemd-cron

2. systemd timers

3. systemd-schedule

4. systemd-jobs

See explanation

Correct answer: systemd timers

Explanation: systemd.timer units are the modern alternative to cron. They offer more flexibility, better integration with systemd, and logging via journalctl. Format: .timer file + associated .service file.

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Question 11

Which command is used to view all active services?

1. systemctl list

2. systemctl list-units --type=service --state=running

3. systemctl show-all

4. systemctl services

See explanation

Correct answer: systemctl list-units --type=service --state=running

Explanation: systemctl list-units --type=service lists all services. --state=running filters only the active ones. systemctl list-units --type=service --all also shows inactive ones.

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Question 12

Which command is used to view active systemd timers?

1. systemctl timers

2. systemctl list-timers

3. systemctl show-timers

4. timers list

See explanation

Correct answer: systemctl list-timers

Explanation: systemctl list-timers displays all systemd timers with their next execution. systemctl list-timers --all also shows inactive ones. Useful for viewing scheduled systemd tasks.

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Question 13

Which command is used to view system logs in real-time?

1. journalctl

2. journalctl -f

3. journalctl --follow

4. tail -f /var/log/syslog

See explanation

Correct answer: journalctl -f

Explanation: journalctl -f follows logs in real-time (like tail -f). journalctl -u service -f follows logs of a specific service. Ctrl+C to stop.

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Question 14

Which command is used to view logs since the last boot?

1. journalctl --boot

2. journalctl -b

3. journalctl --since-boot

4. journalctl boot

See explanation

Correct answer: journalctl -b

Explanation: journalctl -b displays logs since the last boot. journalctl -b -1 shows logs from the previous boot. journalctl --list-boots lists all available boots.

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Question 15

Which command is used to mask a service at startup?

1. systemctl hide service

2. systemctl mask service

3. systemctl disable service

4. systemctl block service

See explanation

Correct answer: systemctl mask service

Explanation: sudo systemctl mask service completely prevents a service from starting (even manually). Creates a symbolic link to /dev/null. systemctl unmask service removes the mask. Stronger than disable.

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Question 16

Which command is used to view a service's dependencies?

1. systemctl deps service

2. systemctl list-dependencies service

3. systemctl show-deps service

4. systemctl dependencies service

See explanation

Correct answer: systemctl list-dependencies service

Explanation: systemctl list-dependencies service displays the dependency tree of a service (required services). --reverse shows services that depend on it. Useful for understanding startup order.

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Question 17

Which command is used to view cron job logs on Ubuntu 24.04?

1. /var/log/cron

2. journalctl -u cron or grep CRON /var/log/syslog

3. /var/log/crontab

4. cronlog

See explanation

Correct answer: journalctl -u cron or grep CRON /var/log/syslog

Explanation: journalctl -u cron displays cron service logs. grep CRON /var/log/syslog searches for cron entries in system logs. Logs show executions and errors of cron jobs.

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Question 18

Which command is used to create a custom systemd service?

1. systemctl create service

2. Create a .service file in /etc/systemd/system/

3. systemctl new service

4. systemctl add service

See explanation

Correct answer: Create a .service file in /etc/systemd/system/

Explanation: To create a custom service, create a file /etc/systemd/system/my-service.service with the configuration. Then sudo systemctl daemon-reload and sudo systemctl enable my-service. The file must follow the systemd unit format.

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Question 19

What is the syntax to run a cron job every day at 2:00 AM?

1. 0 2 * * *

2. 0 2 * * *

3. 2 0 * * *

4. • • 2 * *

See explanation

Correct answer: 0 2 * * *

Explanation: 0 2 * * * means: minute 0, hour 2, every day, every month, every day of the week = every day at 2:00 AM. Format: minute hour day month weekday command.

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Question 20

Which command is used to view systemd timers with their next executions?

1. systemctl timers

2. systemctl list-timers

3. systemctl show-timers

4. timers status

See explanation

Correct answer: systemctl list-timers

Explanation: systemctl list-timers displays all active timers with their last and next execution. systemctl list-timers --all also shows inactive ones. Format: NEXT (next), LEFT (time left), LAST (last).

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Question 21

Which command is used to restart a service?

1. systemctl reload service

2. systemctl restart service

3. systemctl reset service

4. systemctl cycle service

See explanation

Correct answer: systemctl restart service

Explanation: sudo systemctl restart service stops and then restarts a service. systemctl reload service reloads the configuration without restarting (if the service supports it). restart is safer but may interrupt the service.

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Question 22

Which command is used to check if a service is enabled at startup?

1. systemctl status service

2. systemctl is-enabled service

3. systemctl enabled service

4. systemctl check-enabled service

See explanation

Correct answer: systemctl is-enabled service

Explanation: systemctl is-enabled service returns "enabled", "disabled", or "masked". Useful in scripts to check the state. systemctl is-active service checks if the service is currently active.

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Question 23

Which directory contains scripts executed daily by cron/anacron?

1. /etc/cron.daily

2. /etc/cron.daily

3. /var/cron/daily

4. /usr/cron/daily

See explanation

Correct answer: /etc/cron.daily

Explanation: /etc/cron.daily/ contains scripts executed daily. Similar: /etc/cron.hourly/, /etc/cron.weekly/, /etc/cron.monthly/. These scripts are executed by run-parts or anacron.

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Question 24

Which command is used to view a service's logs from the past hour?

1. journalctl -u service --since 1h

2. journalctl -u service --since "1 hour ago"

3. journalctl -u service --last 1h

4. journalctl -u service --time 1h

See explanation

Correct answer: journalctl -u service --since "1 hour ago"

Explanation: journalctl -u service --since "1 hour ago" displays logs from the past hour. Other formats: --since today, --since "2024-12-01 10:00:00", --until "1 hour ago". Very flexible for time filtering.

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Question 25

Which command is used to view all failed services?

1. systemctl failed

2. systemctl --failed

3. systemctl list-failed

4. systemctl show-failed

See explanation

Correct answer: systemctl --failed

Explanation: systemctl --failed or systemctl list-units --state=failed displays all failed services. Useful for diagnosing startup issues. Then check with systemctl status service to see the error.

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Question 26

What is the crontab syntax to run a task every Monday at 9:00 AM?

1. 0 9 * * 0

2. 0 9 * * 1

3. 9 0 * * 1

4. 0 9 1 * *

See explanation

Correct answer: 0 9 * * 1

Explanation: 0 9 * * 1 = minute 0, hour 9, every day, every month, Monday (1). Days of the week: 0 or 7 = Sunday, 1 = Monday, 2 = Tuesday, ..., 6 = Saturday.

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Question 27

Which command is used to view system logs from today?

1. journalctl --today

2. journalctl --since today

3. journalctl today

4. journalctl -d today

See explanation

Correct answer: journalctl --since today

Explanation: journalctl --since today displays logs since midnight today. Other options: --since yesterday, --since "2024-12-01", --since "1 hour ago". Very useful for filtering recent logs.

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Question 28

Which command is used to reload a service's configuration without restarting it?

1. systemctl restart service

2. systemctl reload service

3. systemctl refresh service

4. systemctl reload-config service

See explanation

Correct answer: systemctl reload service

Explanation: systemctl reload service reloads a service's configuration without stopping it (if the service supports it). Gentler than restart as it does not interrupt active connections. Not all services support reload.

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Question 29

Which command is used to view systemd units of type timer?

1. systemctl timers

2. systemctl list-units --type=timer

3. systemctl show-timers

4. systemctl --type timer

See explanation

Correct answer: systemctl list-units --type=timer

Explanation: systemctl list-units --type=timer lists all systemd timers. systemctl list-timers is a shorter alias that also shows next executions. Useful for viewing all scheduled systemd tasks.

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Question 30

Which command is used to start a systemd timer?

1. systemctl run timer

2. systemctl start timer.timer

3. systemctl activate timer

4. timer start

See explanation

Correct answer: systemctl start timer.timer

Explanation: sudo systemctl start my-timer.timer starts a systemd timer. systemctl enable my-timer.timer enables it at startup. The timer must have an associated .service file containing the command to execute.

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Quiz Result

Congratulations on completing the Module 8 quiz!

Score:

• 25-30 correct answers: Excellent! You master service management and advanced cron.
• 20-24 correct answers: Very good! Review the concepts where you had difficulties.
• 15-19 correct answers: Good! Review the chapters on services and cron.
• Less than 15: Recommended to review the module before continuing.

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Next Steps

Now that you have validated your knowledge:

Module 9: System Security
Practical Labs: Practice services and cron with Module 8 labs

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Quiz created on: December 2024 - Tested on Ubuntu 24.04