sudo for elevated privileges in Linux CLI - Practice Problems & Coding Challenges

Challenge - 5 Problems

💻 Command Output

intermediate

What is the output of this sudo command?

You run the command sudo -l as a normal user. What does this command show?

Linux CLI

sudo -l

A Lists the commands the user can run with sudo, possibly without a password

B Shows the current user's password

C Displays the system's uptime

D Starts a root shell immediately

💡 Hint

Think about what 'sudo -l' is used for in daily tasks.

The command 'sudo -l' lists the commands that the current user is allowed to run with sudo privileges, often without needing to enter a password.

💻 Command Output

intermediate

What happens when you run this sudo command?

What is the output or effect of running sudo echo 'Hello' in a terminal?

Linux CLI

sudo echo 'Hello'

A Prints 'Hello' to the terminal

B Prints an error about permission denied

C Runs echo as root but prints 'Hello' as the normal user

D Does nothing and returns to prompt silently

💡 Hint

Consider how sudo affects simple commands like echo.

The command runs echo with sudo, so it prints 'Hello' to the terminal as expected.

🔧 Debug

advanced

Why does this sudo command fail?

You try to run sudo cat /etc/shadow but get a 'Permission denied' error. What is the most likely reason?

Linux CLI

sudo cat /etc/shadow

A The cat command is not installed on the system

B The /etc/shadow file does not exist

C You need to use 'su' instead of 'sudo' to read this file

D Your user is not in the sudoers file and cannot run sudo commands

💡 Hint

Think about user permissions and sudo access.

If your user is not allowed to use sudo, running sudo commands will fail with permission errors even if the command is correct.

🧠 Conceptual

advanced

What does the sudoers file control?

Which of the following best describes the purpose of the sudoers file?

A It stores encrypted passwords for all users

B It defines which users can run which commands with sudo privileges

C It logs all sudo command executions

D It contains system-wide environment variables

💡 Hint

Think about how sudo controls access.

The sudoers file controls who can run sudo and what commands they can run with elevated privileges.

🚀 Application

expert

How to run a command as another user with sudo?

You want to run the command whoami as the user 'alice' using sudo. Which command will do this correctly?

A sudo --user=whoami alice

B sudo whoami -u alice

C sudo -u alice whoami

D sudo alice whoami

💡 Hint

Look for the correct sudo option to specify a different user.

The option '-u' followed by the username runs the command as that user.

Practice

1. What is the main purpose of using sudo in Linux?

easy

A. To create a new user account

B. To switch to another user account permanently

C. To list files in a directory

D. To run commands with higher privileges than a normal user

Solution

1. Step 1: Understand what sudo does

   sudo allows a user to run commands with elevated privileges, usually root access.

2. Step 2: Compare options with sudo purpose

   Only To run commands with higher privileges than a normal user describes running commands with higher privileges, which matches sudo's main use.

3. Final Answer:

   To run commands with higher privileges than a normal user -> Option D

4. Quick Check:

   sudo = elevated privileges [OK]

Hint: sudo means run as superuser or admin [OK]

Common Mistakes:

• Confusing sudo with user switching commands
• Thinking sudo creates users
• Assuming sudo lists files

2. Which of the following is the correct syntax to run the command apt update with elevated privileges?

easy

A. sudo apt update

B. apt sudo update

C. sudo -u apt update

D. apt update sudo

Solution

1. Step 1: Recall the correct sudo syntax

   The correct syntax is sudo [command], so sudo apt update is valid.

2. Step 2: Check each option

   Options A, B, and D place sudo incorrectly or misuse flags.

3. Final Answer:

   sudo apt update -> Option A

4. Quick Check:

   sudo before command = correct syntax [OK]

Hint: Put sudo before the command to elevate it [OK]

Common Mistakes:

• Placing sudo after the command
• Using sudo with wrong flags
• Mixing sudo with user flags incorrectly

3. What will be the output of the command sudo whoami if run by a normal user?

medium

A. root

B. sudo

C. normal user name

D. Permission denied

Solution

1. Step 1: Understand what whoami does

   whoami prints the current user's name.

2. Step 2: Effect of sudo on whoami

   Running sudo whoami runs the command as root, so it prints root.

3. Final Answer:

   root -> Option A

4. Quick Check:

   sudo changes user to root for command [OK]

Hint: sudo runs command as root user [OK]

Common Mistakes:

• Expecting normal username output
• Thinking sudo prints 'sudo'
• Assuming permission denied without sudo

4. You try to run sudo apt-get update but get the error: sudo: command not found. What is the most likely cause?

medium

A. You typed the command incorrectly

B. You are not logged in as root

C. The sudo package is not installed or not in PATH

D. You need to use su instead of sudo

Solution

1. Step 1: Analyze the error message

   sudo: command not found means the system cannot find the sudo program.

2. Step 2: Identify common reasons

   This usually happens if sudo is not installed or its location is missing from the PATH environment variable.

3. Final Answer:

   The sudo package is not installed or not in PATH -> Option C

4. Quick Check:

   command not found = missing sudo or PATH [OK]

Hint: command not found means sudo missing or PATH wrong [OK]

Common Mistakes:

• Assuming user login affects sudo command presence
• Thinking command typo causes 'command not found'
• Confusing su and sudo usage errors

5. You want to run a script backup.sh that requires root permissions. Which command correctly runs it with sudo and ensures the script's environment variables are preserved?

hard

A. sudo ./backup.sh

B. sudo -E ./backup.sh

C. sudo -u root ./backup.sh

D. sudo --preserve-env=ALL ./backup.sh

Solution

1. Step 1: Understand environment preservation with sudo

   By default, sudo resets environment variables for security. The -E flag preserves the user's environment.

2. Step 2: Evaluate options for preserving environment

   sudo -E ./backup.sh uses -E which preserves environment variables. sudo --preserve-env=ALL ./backup.sh uses a longer form but --preserve-env=ALL is less common and may not be supported everywhere.

3. Final Answer:

   sudo -E ./backup.sh -> Option B

4. Quick Check:

   sudo -E preserves environment variables [OK]

Hint: Use sudo -E to keep environment variables [OK]

Common Mistakes:

• Forgetting environment variables reset by sudo
• Using sudo without -E loses variables
• Confusing -u root with environment preservation