Bash:-:-通过while和shift判断脚本位置参数格式是否合法

if [[ $# -lt  ]];then
  echo "请输入2个位置参数..."
  exit
else
  num=$#
  while(($#>=));do

    case ${num} in
      )
        if ! echo "${1}" | grep -qP "\d+\.\d+\.\d+\.\d+";then
          echo "中心机IP输入格式不对..."
          exit
        fi

        SALT_MASTER_IP=${}
        ;;
      )

        if ! echo "${1}" | grep -qP "AAAA_\w+_(ENGINE|COMMON|WEB)_\d+\.\d+\.\d+\.\d+";then
          echo "salt-minion主机名不对..."
          exit
        fi

        SALT_MINION_LOCAL=${}
        ;;
      *)
        echo "输入超过2个位置参数无效..."
        echo "salt-minion.sh 中心机IP 本地主机名"
        exit
        ;;
    esac

    num=`expr ${num} - `
    shift
  done
fi