Shell编程简单实现四则运算

来源：互联网发布：怎么在mac上下载webex 编辑：程序博客网时间：2024/06/10 11:42
#!/bin/shmain(){        echo  "#############################"        echo  "## usage: num1 +/-/#// num2##"        echo  "## example: 1 + 1          ##"        echo  "## '*' is replaced by '#'  ##"        echo  "#############################"        while [ 1 ]        do        echo "## please select :         ##"        echo "## 1.cal                   ##"        echo "## 0.exit                  ##"                read select                if [ "$select" = "1" ]                then                        cal;                elif [ "$select" = "0" ]                then                        break;                fi        done}cal(){        echo "please enter number,as: number1 sign number2:"        read str        num1=`echo $str|cut -d' ' -f1`        num2=`echo $str|cut -d' ' -f3`        sign=`echo $str|cut -d' ' -f2`        case $sign in        +)                sum=`expr $num1 + $num2`;                echo "$num1 $sign $num2 = $sum";;        -)                sum=`expr $num1 - $num2`;                echo "$num1 $sign $num2 = $sum";;        \#)                sum=`expr $num1 \* $num2`;                echo "$num1 * $num2 = $sum";;        /)                sum=`expr $num1 / $num2`;                echo "$num1 $sign $num2 = $sum";;        *)                echo "your enter is wrong";;        esac    echo "please enter to continue"        read cto}main