LInux Shell编程初探

#!/bin/bash while [ "0" == "0" ] do        read -p "please in put the number1 :" num1        read -p "please in put the number2 : " num2        read -p "please in put your wants : " flag        if [ "$num1" == "0" ] && [ "$num2" == "0" ];then        break        fi        case $flag in                "+")                        echo $(($num1+$num2))                        ;;                "-")                        echo $(($num1-$num2))                        ;;                "*")                        echo $(($num1*$num2))                        ;;                "/")                        echo $(($num1/$num2))                        ;;                "%")                        echo $(($num1%$num2))                        ;;        esac        read -p "do you want to continue : " yn        if [ "$yn" == "N" ] || [ "$yn" == "n" ];then        break        fi done        exit 0