systemctl for service management in Linux CLI - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

What is the output of checking a service status?

You run the command systemctl status sshd on a Linux system where the SSH service is active and running. What will the command output include?

Linux CLI

systemctl status sshd

A Active: active (running) since [date and time]; shows process ID and memory usage

B Active: inactive (dead); no process ID shown

C Failed to start sshd.service: Unit sshd.service not found.

D Active: activating (start) since [date and time]; no process ID shown

💡 Hint

Think about what 'active and running' means for a service status.

When a service is running, systemctl status shows it as active (running) with details like start time and process ID.

💻 Command Output

intermediate

What happens when you disable a service?

You run systemctl disable apache2 on a Linux system. What is the immediate effect of this command?

Linux CLI

systemctl disable apache2

A The apache2 service is masked and cannot be started manually.

B The apache2 service is restarted immediately.

C The apache2 service is stopped immediately.

D The apache2 service is prevented from starting automatically on boot.

💡 Hint

Disabling a service affects its behavior on system startup.

Disabling a service removes its automatic start on boot but does not stop it immediately.

📝 Syntax

advanced

Which command correctly restarts a service immediately?

You want to restart the nginx service immediately using systemctl. Which command is correct?

A systemctl enable nginx.service

B systemctl restart nginx.service

C systemctl reload nginx.service

D systemctl stop nginx.service && systemctl start nginx.service

💡 Hint

Restart means stop and start in one command.

The restart command stops and then starts the service immediately.

💻 Command Output

advanced

What error appears when starting a non-existent service?

You run systemctl start foobar where no service named 'foobar' exists. What error message will systemctl show?

Linux CLI

systemctl start foobar

A Failed to start foobar.service: Unit foobar.service not found.

B foobar.service started successfully.

C Permission denied while starting foobar.service.

D foobar.service is already running.

💡 Hint

Think about what happens if the service file is missing.

systemctl reports 'Unit not found' when the service does not exist.

🚀 Application

expert

How to check which services are enabled at boot?

You want to list all services that are enabled to start automatically at boot on a Linux system using systemctl. Which command will give you this list?

A systemctl list-units --type=service --state=running

B systemctl status --all

C systemctl list-unit-files --state=enabled

D systemctl show --property=Enabled

💡 Hint

Look for a command that lists unit files filtered by enabled state.

The command 'systemctl list-unit-files --state=enabled' lists all enabled services at boot.