#!/bin/bash

# Function to check if a file exists
check_file_exists() {
    if [ -f "$1" ]; then
        echo "File '$1' exists."
    else
        echo "File '$1' does not exist."
    fi
}

# Function to count the number of lines in a file
count_lines() {
    local lines=$(wc -l < "$1")
    echo "Number of lines in '$1': $lines"
}

# Function to create a new file
create_file() {
    echo "Enter text to write into the file (press CTRL+D to save):"
    cat > "$1"
    echo "File '$1' created with the entered text."
}

# Main menu
while true; do
    echo "===== Bash Script Menu ====="
    echo "1. Check if a file exists"
    echo "2. Count the number of lines in a file"
    echo "3. Create a new file"
    echo "4. Exit"

    read -p "Enter your choice [1-4]: " choice

    case $choice in
        1)
            read -p "Enter the filename to check: " filename
            check_file_exists "$filename"
            ;;
        2)
            read -p "Enter the filename to count lines: " filename
            count_lines "$filename"
            ;;
        3)
            read -p "Enter the filename to create: " filename
            create_file "$filename"
            ;;
        4)
            echo "Exiting the script. Goodbye!"
            exit 0
            ;;
        *)
            echo "Invalid choice. Please enter a valid option [1-4]."
            ;;
    esac
    echo
done