Bash Script to Delete User Account Safely

Use the Bash command sudo userdel -r username to delete a user account and its home directory; in a script, replace username with the target user.

Examples

Inputusername=john

OutputUser 'john' deleted along with home directory.

Inputusername=alice

OutputUser 'alice' deleted along with home directory.

Inputusername=nonexistent

Outputuserdel: user 'nonexistent' does not exist

How to Think About It

To delete a user account in Bash, the script needs to accept the username, check if the user exists, then run the system command userdel with the -r option to remove the user and their home directory safely.

Algorithm

1

Get the username input from the user or argument

2

Check if the user exists on the system

3

If user exists, run <code>sudo userdel -r username</code> to delete user and home directory

4

Print success or error message based on the command result

Code

bash

#!/bin/bash

if [ "$#" -ne 1 ]; then
  echo "Usage: $0 username"
  exit 1
fi

username=$1

if id "$username" &>/dev/null; then
  sudo userdel -r "$username" && echo "User '$username' deleted along with home directory." || echo "Failed to delete user '$username'."
else
  echo "User '$username' does not exist."
fi

Output

User 'john' deleted along with home directory.

Dry Run

Let's trace deleting user 'john' through the code

1

Check argument count

Input arguments count is 1, proceed.

2

Check if user exists

Command id john succeeds, user exists.

3

Delete user

Run sudo userdel -r john, command succeeds.

Step	Action	Result
1	Check argument count	1 argument found, OK
2	Check if user exists	User 'john' exists
3	Delete user	User 'john' deleted successfully

Why This Works

Step 1: Check input argument

The script uses $# to ensure exactly one username is provided to avoid errors.

Step 2: Verify user existence

The id command checks if the user exists before attempting deletion to prevent errors.

Step 3: Delete user safely

The userdel -r command removes the user and their home directory, cleaning up all user data.

Alternative Approaches

Delete user without removing home directory

bash

#!/bin/bash

username=$1
if id "$username" &>/dev/null; then
  sudo userdel "$username" && echo "User '$username' deleted without home directory." || echo "Failed to delete user '$username'."
else
  echo "User '$username' does not exist."
fi

This keeps the user's home directory and files intact, useful if you want to preserve data.

Force delete user even if logged in

bash

#!/bin/bash

username=$1
if id "$username" &>/dev/null; then
  sudo userdel -r -f "$username" && echo "User '$username' force deleted." || echo "Failed to force delete user '$username'."
else
  echo "User '$username' does not exist."
fi

The <code>-f</code> option forces deletion even if the user is logged in, but use with caution.

Complexity: O(1) time, O(1) space

Time Complexity

The script runs a fixed number of system commands regardless of input size, so time complexity is constant O(1).

Space Complexity

The script uses a few variables and no extra data structures, so space complexity is O(1).

Which Approach is Fastest?

All approaches run system commands with similar speed; forcing deletion may be slightly slower due to extra checks.

Approach	Time	Space	Best For
Delete with home directory (-r)	O(1)	O(1)	Complete user removal
Delete without home directory	O(1)	O(1)	Preserving user files
Force delete (-f)	O(1)	O(1)	Removing logged-in users