匹配 Yes,YES,YeS,yES,yEs ...

    	
read -p "Do you want to continue [Y/n]?" BOOLEAN

case $BOOLEAN in
    [yY][eE][sS])
        echo 'Thanks' $BOOLEAN
        ;;
    [yY]|[nN])
        echo 'Thanks' $BOOLEAN
        ;;
    'T'|'F')
        echo 'Thanks' $BOOLEAN
        ;;
    [Tt]ure|[Ff]alse)
        echo 'Thanks' $BOOLEAN
        ;;
    *)
        exit 1
        ;;
esac