if [ $1 ] && [ $2 ] && [ $3 ]; then

    echo app name: $1
    echo icon: $2
    echo url: $3
    echo please ensure your url either contains http://, or https://
    echo is this correct? y/n: 
    read input

    while [[ $input != 'y' && $input != 'n' ]]; do
        echo not a valid input. please input y or n
        read input
        done

    case $input in

        y)
            mkdir "$1"_app
            cd "$1"_app
            echo "{\"manifest_version\": 2," >> manifest.json
            echo "\"name\": \"$1\"," >> manifest.json
            echo "\"version\": \"1.0\"," >> manifest.json
            echo "\"icons\": {\"16\": \"$2\"," >> manifest.json
            echo "\"128\": \"$2\"}," >> manifest.json
            echo "\"app\": {" >> manifest.json
            echo "\"urls\": [" >> manifest.json 
            echo "\"$3\"]," >> manifest.json
            echo "\"launch\": {\"web_url\": \"$3\"}}}" >> manifest.json
            mv ../$2 ./
        ;;
    
        n) 
            echo everyone makes mistakes, try again
        ;;
    
    esac

    else
        echo incorrect syntax! please write it as:
        echo Script app_name app_icon app_url
    fi