User Account Management Using shell Scripting

Task 1: Account Creation

Steps:

1. Check if the username already exists before creating the account.

2. Prompt for username and password securely.

3. Create the new account and set the password.

4. Confirm successful account creation.

Execution:

#!/bin/bash

# Function to create a user account
create_user() {
    read -p "Enter new username: " username
    if id "$username" &>/dev/null; then
        echo "Error: User '$username' already exists."
        exit 1
    fi
    read -s -p "Enter password for $username: " password
    echo
    sudo useradd "$username"
    echo "$username:$password" | sudo chpasswd
    echo "User '$username' created successfully."
}

create_user

Explanation:

• id "$username" checks if the user already exists.

• read -s -p ensures password entry is hidden.

• useradd creates the account.

• chpasswd sets the password.

• Prints success confirmation.

---

Task 2: Account Deletion

Steps:

1. Check if the username exists before deletion.

2. Prompt for username to be deleted.

3. Delete the account and confirm.

Execution:

delete_user() {
    read -p "Enter username to delete: " username
    if ! id "$username" &>/dev/null; then
        echo "Error: User '$username' does not exist."
        exit 1
    fi
    sudo userdel -r "$username"
    echo "User '$username' deleted successfully."
}

delete_user

Explanation:

• id "$username" ensures the user exists before deletion.

• userdel -r removes the user along with their home directory.

• Prints a success message.

---

Task 3: Password Reset

Steps:

1. Check if the username exists before resetting password.

2. Prompt for username and new password.

3. Reset the password securely.

4. Confirm password change.

Execution:

reset_password() {
    read -p "Enter username to reset password: " username
    if ! id "$username" &>/dev/null; then
        echo "Error: User '$username' does not exist."
        exit 1
    fi
    read -s -p "Enter new password: " password
    echo
    echo "$username:$password" | sudo chpasswd
    echo "Password for '$username' reset successfully."
}

reset_password

Explanation:

• Ensures the account exists before modifying credentials.

• Uses chpasswd to securely reset passwords.

• Prints confirmation.

---

Task 4: List User Accounts

Steps:

1. Fetch all system users and their corresponding UIDs.

2. Format the output for readability.

Execution:

list_users() {
    echo "User Accounts on the System:"
    cut -d: -f1,3 /etc/passwd | column -t -s:
}

list_users

Explanation:

• Extracts usernames and their UIDs from /etc/passwd.

• Formats output neatly using column -t -s:.

---

Task 5: Help and Usage

Steps:

1. Display available command options and their usage.

Execution:

usage() {
    echo "Usage: user_management.sh [OPTION]"
    echo "Options:"
    echo "  -c, --create    Create a new user account"
    echo "  -d, --delete    Delete an existing user account"
    echo "  -r, --reset     Reset password for an existing user account"
    echo "  -l, --list      List all user accounts"
    echo "  -h, --help      Display usage information"
}

usage

Explanation:

• Prints all available command-line options.

• Ensures users understand script functionality.

---

Final Implementation: Running the Full Script

Now, let's package everything into one script (user_management.sh) with proper argument handling:

#!/bin/bash

# Function to display usage
usage() {
    echo "Usage: $0 [-c|--create] [-d|--delete] [-r|--reset] [-l|--list] [-h|--help]"
}

create_user() {
    read -p "Enter new username: " username
    if id "$username" &>/dev/null; then
        echo "Error: User '$username' already exists."
        exit 1
    fi
    read -s -p "Enter password for $username: " password
    echo
    sudo useradd "$username"
    echo "$username:$password" | sudo chpasswd
    echo "User '$username' created successfully."
}

delete_user() {
    read -p "Enter username to delete: " username
    if ! id "$username" &>/dev/null; then
        echo "Error: User '$username' does not exist."
        exit 1
    fi
    sudo userdel -r "$username"
    echo "User '$username' deleted successfully."
}

reset_password() {
    read -p "Enter username to reset password: " username
    if ! id "$username" &>/dev/null; then
        echo "Error: User '$username' does not exist."
        exit 1
    fi
    read -s -p "Enter new password: " password
    echo
    echo "$username:$password" | sudo chpasswd
    echo "Password for '$username' reset successfully."
}

list_users() {
    echo "User Accounts on the System:"
    cut -d: -f1,3 /etc/passwd | column -t -s:
}

case "$1" in
    -c|--create) create_user ;;
    -d|--delete) delete_user ;;
    -r|--reset) reset_password ;;
    -l|--list) list_users ;;
    -h|--help) usage ;;
    *) echo "Invalid option! Use -h or --help for usage."; exit 1 ;;
esac

How to Use the Script

1. Create a User → ./user_management.sh -c

2. Delete a User → ./user_management.sh -d

3. Reset a Password → ./user_management.sh -r

4. List Users → ./user_management.sh -l

5. Show Help → ./user_management.sh -h

This script follows DevOps best practices, ensuring security, error handling, and user-friendly execution.