su (switch user) in Linux CLI - Mini Project: Build & Apply

Switch User with su Command

📖 Scenario: You are managing a Linux system where you need to switch between users to perform different tasks. Using the su command helps you switch to another user account temporarily.

🎯 Goal: Learn how to use the su command to switch users, set a target user variable, and verify the current user after switching.

📋 What You'll Learn

Create a variable holding the target username

Use the su command with the target username

Check the current user after switching

Print the current user to confirm the switch

💡 Why This Matters

🌍 Real World

System administrators often need to switch users to perform tasks with different permissions. Automating this with scripts saves time and reduces errors.

💼 Career

Knowing how to use the su command and automate user switching is useful for Linux system administrators, DevOps engineers, and anyone managing multi-user systems.

1

Set the target user variable

Create a variable called target_user and set it to the exact string guest.

Linux CLI

# Create a variable called target_user and set it to 'guest'
target_user = ''  # Your code here

Need a hint?

Use target_user = 'guest' to store the username.

2

Switch user using su command

Write a command string called switch_command that uses su with the -c option to run whoami as the user stored in target_user. Use double quotes and f-string style formatting exactly as switch_command = f"su {target_user} -c 'whoami'".

Linux CLI

target_user = 'guest'
# Create switch_command to run 'whoami' as target_user using su
switch_command = ''  # Your code here

Need a hint?

Use f"su {target_user} -c 'whoami'" to build the command string.

3

Execute the switch command and capture output

Use the subprocess module to run the command stored in switch_command. Import subprocess and use subprocess.run with shell=True, capture the output, decode it to a string, and store it in a variable called current_user. Use current_user = subprocess.run(switch_command, shell=True, capture_output=True).stdout.decode().strip() exactly.

Linux CLI

target_user = 'guest'
switch_command = f"su {target_user} -c 'whoami'"
# Import subprocess and run switch_command, store output in current_user
# Your code here

Need a hint?

Use import subprocess and subprocess.run(...).stdout.decode().strip() to get the output.

4

Print the current user

Write a print statement to display the value of current_user exactly as print(current_user).

Linux CLI

import subprocess
target_user = 'guest'
switch_command = f"su {target_user} -c 'whoami'"
current_user = subprocess.run(switch_command, shell=True, capture_output=True).stdout.decode().strip()
# Print the current_user
# Your code here

Need a hint?

Use print(current_user) to show the switched user.