Welcome to Day 3 of our Bash Scripting Challenge! 😊 Today, we'll be using our awesome Bash scripting skills to handle user management. Together, we'll create a handy script that lets us add or remove users, reset passwords, list users, and even show helpful usage info for our script. Let's get started!

✔ Account Creation 🔎:

In this task, we need to write a bash script that creates a user account. Here, the script should prompt the user to enter a new username and password. The script should check if the username already exists. If the user exists then the script should pass a statement throwing an error else it should create a user for you. Let's script it!

  # Create a new user account 

  if [ "$1" == "-c" ] || [ "$1" == "--create" ]
   then
      read -p "Enter a new username: " username
      id "$username" &>/dev/null
      if [ $? -eq 0 ]; then
          echo "The username '$username' already exists. Please choose a different username."
      else
          sudo useradd -m "$username"
          sudo passwd "$username"
          echo "User account '$username' created successfully."
      fi

❌Account Deletion 🚫:

Now, let's try to perform the deletion of a user account. the function initially verifies whether the specified user exists. If the user exists, it proceeds to delete the account; otherwise, it displays an error message.

delete_user(){
    echo
    read -p "Enter username : " username
    check_user_exists "$username"
    if (( $? == 0 ))
    then
        sudo userdel -r "$username"
        if (( $? == 0 ))
        then 
            echo User - "$username", deleted successfully
        else
            echo Error : unable to delete user
        fi
    else
        echo Error : $username user doesnot exists
    fi
    echo
}

📌Password Reset 🔐:

Next, we'll implement the password reset feature. The script should ask for the username and the new password. If the username doesn't exist, the script should inform and exit.

function if_user_exists() {
    if id "$1" &>/dev/null; then
        return 0
    else
        return 1
    fi
}

function reset_passwd() {
    read -p "Enter the username to reset password: " username
    if if_user_exists "$username"; then
        read -s -p "Enter the password for $username: " password
        echo "$username:$password" | sudo chpasswd
        echo
        echo "Password for user '$username' reset successfully."
    else
        echo "Error: The username '$username' does not exist. Please enter a valid username."
    fi
}

☀List User Accounts 📝:

Now, let's try to implement a script that allows us to list all the user accounts along with their UIDs.

list_users(){
    echo
    echo "List of users on the system:"
    sudo cat /etc/passwd | awk -F: '{print $1}'
    echo
}

🍁Print script usage info✏:

Now finally we need to add a help option to display usage information and the available command-line options. So let's write a function for the same.

  if [ "$1" == "-h" ] || [ "$1" == "--help" ]
   then
      echo "Usage: $0 [OPTIONS]"
      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 on the system."
      echo "  -h, --help    Show this help message"
      echo "  -i, --info    Display the user information"
      echo "  -m, --modify  Modify user properties"
      exit 0
  fi

🔅Putting it all together📂:

In this example, a case statement is used to check user input from the command line and execute the corresponding function.:

#!/bin/bash

# Check for help option

if [ "$1" == "-h" ] || [ "$1" == "--help" ]
 then
    echo "Usage: $0 [OPTIONS]"
    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 on the system."
    echo "  -h, --help    Show this help message"
    echo "  -i, --info    Display the user information"
    echo "  -m, --modify  Modify user properties"
    exit 0
fi

# Create a new user account 

if [ "$1" == "-c" ] || [ "$1" == "--create" ]
 then
    read -p "Enter a new username: " username
    id "$username" &>/dev/null
    if [ $? -eq 0 ]; then
        echo "The username '$username' already exists. Please choose a different username."
    else
        sudo useradd -m "$username"
        sudo passwd "$username"
        echo "User account '$username' created successfully."
    fi

# Delete an existing user account 

elif [ "$1" == "-d" ] || [ "$1" == "--delete" ]
 then
    read -p "Enter the username to delete: " username
    id "$username" &>/dev/null
    if [ $? -eq 0 ]; then
        sudo userdel -r "$username"
        echo "Done! Account '$username' deleted successfully."
    else
        echo "Sorry, The username '$username' doesn't exist.Please enter a valid username"

    fi

# Reset password for a user account

elif [ "$1" == "-r" ] || [ "$1" == "--reset" ]
 then
    read -p "Enter the username to reset password: " username
    id "$username" &>/dev/null
    if [ $? -eq 0 ]; then
        sudo passwd "$username"
        echo "Password for '$username' reset successfully."
    else
        echo "Uh-oh! '$username' doesn't exist."
    fi

# List all the user accounts

elif [ "$1" == "-l" ] || [ "$1" == "--list" ]
 then
    echo "User accounts on the system :"
    echo "Username   UID"
    echo "----------------"
    awk -F: '{print $1 "   " $3}' /etc/passwd


# Display detailed information about a user account

elif [ "$1" == "-i" ] || [ "$1" == "--info" ]
 then
    read -p "Enter username to display information: " info_username
    if id "$info_username" &>/dev/null; then
        finger "$info_username"
    else
        echo "Error: Username '$info_username' does not exist."
    fi

# Modify user accoun properties

elif [ "$1" == "-m" ] || [ "$1" == "--modify" ]
 then
    read -p "Enter username to modify properties: " modify_username
    if id "$modify_username" &>/dev/null; then
        read -p "Enter new username (leave empty to keep current): " new_username
        read -p "Enter new UID (leave empty to keep current): " new_uid
        if [[ -n "$new_username" ]]; then
            sudo usermod -l "$new_username" "$modify_username"
            echo "Username for user '$modify_username' changed to '$new_username'."
        fi
        if [[ -n "$new_uid" ]]; then
            sudo usermod -u "$new_uid" "$modify_username"
            echo "UID for user '$modify_username' changed to '$new_uid'."
        fi
    else
        echo "Error: Username '$modify_username' does not exist."
    fi

# Handle invalid options

else
    echo "Oops! Invalid option: $1"
    echo "Use '$0 -h' to see available options."
    exit 1
fi

Instructions for running the script:

Write the script and save it as user_management.sh.
Make the script executable using chmod: chmod +x user_management.sh.
Execute the script for the required options as follows:
- Create a new user: ./user_management.sh -c or ./user_management.sh --create
- Delete an existing user: ./user_management.sh -d or ./user_management.sh --delete
- Reset user password: ./user_management.sh -r or ./user_management.sh --reset
- List all user accounts: ./user_management.sh -l or ./user_management.sh --list
- Display help: ./user_management.sh -h or ./user_management.sh --help
  
  Now, you have a powerful Bash script to manage user accounts on your system, this script will save you time and effort, ensuring smooth user account management.
  
  Thank you for reading. please do share🔄 and click the like👍 to show your support.
  
  Keep learning and happy scripting! 🤗

Day-3 : TWS BashBlaze Challenge

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