shift方式检查传入参数是否为空

function a(){
  haveP="pass"
  while [  $# -ne 0 ]
  do
    if [ -z $1 ];then
      haveP="false"  
    fi
    shift
   done
   if [ $haveP == "false" ];then
      echo "have empty paramater!!!!"
   fi
}