#!/bin/bashread -t 30 -p "shu ru shu zi:" num1read -t 30 -p "shu ru shu zi:" num2read -t 30 -p "shu ru fu hao:" opeif [ -n "$num1" -a -n "$num2" -a -n "$ope"  ]   then   test1=$( echo $num1 | sed 's/[0-9]//g' )   test2=$( echo $num1 | sed 's/[0-9]//g' )   if [ -z "$test1" -a -z "$test2" ]     then#!/bin/bashread -t 30 -p "shu ru shu zi:" num1read -t 30 -p "shu ru shu zi:" num2read -t 30 -p "shu ru fu hao:" opeif [ -n "$num1" -a -n "$num2" -a -n "$ope"  ]   then   test1=$( echo $num1 | sed 's/[0-9]//g' )   test2=$( echo $num1 | sed 's/[0-9]//g' )   if [ -z "$test1" -a -z "$test2" ]     then       if [ "$ope" == '+' ]         then             sum=$(($sum1+$sum2))       elif [ "$ope" == '-' ]         then             sum=$(($num1-$num2))       elif [ "$ope" == '*' ]        then             sum=$(( $sum1 * $sum2 ))       elif [ "$ope" == '/' ]       then             sum=$(( $sum1 / $sum2 ))  else   echo "shu ru fu hao"   exit 10   fi                                                           else   echo "shu ru shu zi"   exit 11  fi  else  echo "shu ru zi fu"  fi  echo "$num1$ope$num2 : $sum"