Linux シェルスクリプトでユーザー入力を取得する

read -p "Do you want to continue? (Y/y for Yes, any other key for No) " answer
    case $answer in
        [Yy]* ) echo "Program continues..."; break;;
        * ) echo "Program exits."; exit;;
    esac

echo "Do you want to continue? "
select answer in "Yes" "No"; do
    case $answer in
        Yes ) echo "Program continues..."; break;;
        No ) echo "Program exits."; exit;;
    esac
done

if whiptail --yesno "Do you want to continue? " 10 40 ;then
    echo "Program continues...";
else
    echo "Program exits."
fi