useradd and userdel in Linux CLI - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the command to add a new user named 'alice'.

Linux CLI

sudo [1] alice

Drag options to blanks, or click blank then click option'

Auseradd

Buserdel

Cpasswd

Dgroupadd

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'userdel' instead of 'useradd'.

Using 'passwd' which changes passwords, not adds users.

The 'useradd' command is used to add a new user in Linux.

2fill in blank

medium

Complete the command to delete a user named 'bob'.

Linux CLI

sudo [1] bob

Drag options to blanks, or click blank then click option'

Apasswd

Buserdel

Cgroupdel

Duseradd

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'useradd' instead of 'userdel'.

Using 'groupdel' which deletes groups, not users.

The 'userdel' command deletes a user from the system.

3fill in blank

hard

Fix the error in the command to add a user with a home directory.

Linux CLI

sudo useradd [1] alice

Drag options to blanks, or click blank then click option'

A-m

B-r

C-s

D-d

Attempts:

3 left

💡 Hint

Common Mistakes

Using '-d' which sets a custom home directory path but does not create it.

Using '-r' which creates a system user, not a regular user.

The '-m' option creates a home directory for the new user.

4fill in blank

hard

Fill both blanks to delete user 'charlie' and remove their home directory.

Linux CLI

sudo [1] [2] charlie

Drag options to blanks, or click blank then click option'

Auserdel

B-r

C-m

Duseradd

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'useradd' instead of 'userdel'.

Using '-m' which creates a home directory, not removes it.

The 'userdel' command deletes the user, and '-r' removes the home directory.

5fill in blank

hard

Fill all three blanks to add a user 'dave' with a home directory and set their shell to /bin/bash.

Linux CLI

sudo [1] [2] [3] dave

Drag options to blanks, or click blank then click option'

A-m

B-s

Cuseradd

D-r

Attempts:

3 left

💡 Hint

Common Mistakes

Using '-r' which creates a system user, not a regular user.

Putting options in the wrong order or missing the shell option.

Use 'useradd' command with '-m' to create home directory and '-s' to set shell.

Practice

1. What does the useradd command do in Linux?

easy

A. Lists all users on the system

B. Deletes an existing user account

C. Changes the password of a user

D. Creates a new user account

Solution

1. Step 1: Understand the purpose of useradd

   The useradd command is used to create new user accounts on a Linux system.

2. Step 2: Differentiate from other commands

   userdel deletes users, passwd changes passwords, and listing users is done by other commands like cat /etc/passwd.

3. Final Answer:

   Creates a new user account -> Option D

4. Quick Check:

   useradd = create user [OK]

Hint: Remember: add means create, del means delete [OK]

Common Mistakes:

• Confusing useradd with userdel
• Thinking useradd lists users
• Mixing useradd with password commands

2. Which of the following is the correct syntax to create a user with a home directory?

easy

A. useradd -r username

B. useradd username

C. useradd -m username

D. userdel -m username

Solution

1. Step 1: Identify the option for creating home directory

   The -m option with useradd creates the user's home directory.

2. Step 2: Check other options

   -r is for system users or removing files with userdel, so it is incorrect here.

3. Final Answer:

   useradd -m username -> Option C

4. Quick Check:

   -m means make home directory [OK]

Hint: Use -m with useradd to create home folder [OK]

Common Mistakes:

• Using userdel instead of useradd
• Forgetting the -m option for home directory
• Using -r option with useradd

3. What will be the result of this command sequence?

useradd -m alice
userdel alice

medium

A. User alice is deleted but home directory remains

B. User alice and home directory are deleted

C. User alice is created but deletion fails

D. Syntax error occurs

Solution

1. Step 1: Create user alice with home directory

   useradd -m alice creates user alice and a home folder.

2. Step 2: Delete user alice without -r option

   userdel alice deletes the user but does not remove the home directory unless -r is used.

3. Final Answer:

   User alice is deleted but home directory remains -> Option A

4. Quick Check:

   userdel without -r keeps files [OK]

Hint: userdel needs -r to remove home directory [OK]

Common Mistakes:

• Assuming home directory is deleted without -r
• Thinking userdel fails without -r
• Confusing useradd options with userdel

4. You run userdel -r bob but get an error saying user bob does not exist. What is the likely cause?

medium

A. The home directory is missing

B. User bob was never created

C. You need to use useradd to delete users

D. The -r option is invalid with userdel

Solution

1. Step 1: Understand the error message

   The error says user bob does not exist, so the system cannot delete a non-existent user.

2. Step 2: Check command validity

   userdel -r bob is valid syntax to delete user and home directory, so the error is not due to syntax.

3. Final Answer:

   User bob was never created -> Option B

4. Quick Check:

   User must exist before deletion [OK]

Hint: Check if user exists before deleting [OK]

Common Mistakes:

• Thinking -r is invalid option
• Trying to delete users with useradd
• Assuming home directory missing causes error

5. You want to create a script that adds a user with a home directory and then deletes the user along with all their files. Which commands should you use in order?

hard

A. useradd -m username; userdel -r username

B. useradd username; userdel username

C. userdel -r username; useradd -m username

D. userdel username; useradd username

Solution

1. Step 1: Add user with home directory

   Use useradd -m username to create the user and their home folder.

2. Step 2: Delete user and all files

   Use userdel -r username to remove the user and their home directory and files.

3. Final Answer:

   useradd -m username; userdel -r username -> Option A

4. Quick Check:

   Add with -m, delete with -r for files [OK]

Hint: Add with -m, delete with -r to remove files [OK]

Common Mistakes:

• Deleting before adding user
• Forgetting -m when adding user
• Forgetting -r when deleting user