给shell 脚本加一个启动密码

#!/bin/bash
clear && date
function pass(){
echo -e "请输入脚本启动密码: \c"
while : ;do
   char=`stty cbreak -echo
     dd if=/dev/tty bs=1 count=1 2>/dev/null
     stty -cbreak echo`
   if [ "$char" = "" ];then
     echo
     break
   fi
   PAS="$PAS$char"
   echo -n "*"
done
}

function pass_check(){
while : ;do
if [ `echo "$PAS"| md5sum |awk '{print $1}'` != "4d8702dc88b38fa64defa49bd22ef4e0" ];then
   clear && date
   echo -e "\033[31m 密码错误，请重新输入。\033[0m"
   PAS=''
   pass
else
   echo "密码正确，开始执行脚本....."
   break
fi
done
}
pass
pass_check
echo "asdf"
######### 脚步执行测试：