linux无限执行直到输入制定值退出

#!/bin/bash
flag=1;
while [ $flag -eq 1 ];
do
        read -p "Do you want to continue [Y/N] or input date as yyyyMMdd ?" answer
        case $answer in
        Y | y)
                  echo "fine ,continue $flag";;
        N | n)
                  let flag=0
                  echo "ok,good bye";;
        *)
                 echo "$answer";;
         esac
done