A script for creating and adding a user to a group in Ubuntu

add_user.sh

#!/bin/bash

# Prompt the user to enter the user name.
# Create a new user using useradd .
set_username() {
    read -p "Enter username: " username
    if id "$username" &>/dev/null; then
        echo "User '$username' already exists. Please try a different name."
        set_username
    else sudo useradd $username
	fi
}

# Prompt the user to enter a strong password (8 characters or more) and set it using passwd​.
set_password() {
    while true; do
        read -s -p "Enter a strong password (8 characters or more): " password
        echo
        if [[ ${#password} -ge 8 ]]; then
            echo "$username:$password" | sudo chpasswd
            if [[ $? -eq 0 ]]; then
                echo "Password set successfully."
                break
            else
                echo "Failed to set password. Try again."
            fi
        else
            echo "Password must be at least 8 characters. Try again."
        fi
    done
}

# Prompt the user to enter a default group name.
# Append the entered group name to the user groups using usermod -aG <groupname> <username>​.
adduser_to_group() {
    while true; do
        read -p "Enter a default group name: " groupname
        sudo usermod -aG "$groupname" "$username" 2>/dev/null
        if [[ $? -eq 0 ]]; then
            echo "User '$username' added to group '$groupname'."
            break
        else
            echo "Failed to add user to group '$groupname'. Try again."
        fi
    done
}

# At the end, the script should ask the user to confirm creating the new user with a message. If the user decided not to create the user, delete it using userdel -r <user_name>​.
confirm_creation() {
    read -p "Confirm creating user '$username'? (y/n): " confirm
    if [[ "$confirm" != "y" && "$confirm" != "Y" ]]; then
        sudo userdel -r "$username"
        echo "User '$username' has been deleted."
    else
        echo "User '$username' successfully created."
    fi
}

set_username
set_password
adduser_to_group
confirm_creation