Simple script----Calculator for Linux Beginners

#!bin/bash# Simple Calculator # author: tianzhaogao  (e-mail: [email protected]) num1=initnum2= initcal=initecho  "Welcome to Tian Shao Simple Calculator" read -t 30 -p  "NUM1:"  num1checknum1=$ (echo  " $num 1 " | sed  ' s/[0-9]//g ') while [ -z " $num 1 " -o -n " $checknum 1 "  ]dowhile [ -z  "$num 1"  ]doecho  "Error! the inputing can not"  be empty! " read -t 30 -p  "NUM1:"  num1checknum1=$ (echo  "$num 1"  | sed  ' s/[0-9] G ') donewhile [ -n  "$checknum 1"  ]doecho  "Error inputinng! the type  of inputing must be int! " read -t 30 -p  "NUM1:"  num1checknum1=$ (echo  "$num 1"  | sed  ' s/[0-9] G ') donedoneread -t 30 -p  "num2:"  num2checknum2=$ (echo  "$num 2"  | sed   ' s/[0-9]//g ') while [ -z  "$num 2"  -o -n  "$checknum 2"  ]dowhile [ -z  "$num 2"  ]doecho  "error! the  inputing can not be empty! " read -t 30 -p  "num2:"  num2checknum2=$ (echo  "$num 2"  | sed  ' s/[0-9] G ') donewhile [ -n  "$checknum 2"   ]doecho  "error inputinng! the  Type of inputing must be int! " read -t 30 -p  "num2:"  num2checknum2=$ (echo  "$num 2"  | sed  ' s/[0-9] G ') donedoneread -t 30 -p  "operator:"  calcheckcal=$ (echo  "$cal"  | sed   ' s/[\+\-\*\/]//g ') while [ -z  "$cal"  -o -n  "$checkcal"  ]dowhile [  -z  "$cal"  ]doecho  "error! the inputing can not be empty!" read -t 30 -p  "Operator:"  calcheckcal=$ (echo  "$cal"  | sed  "s/[\+\-\*\/ ]//g ') donewhile [ -n  "$checkcal"  ]doecho  "error inputinng! the type of inputing " must be [' + '  or  '-'  or  ' * '  or  '/']! ' read -t 30 -p  "Operator:"  calcheckcal=$ (echo  "$cal"  | sed  "s/[\+\-\*\/ ]//g ') donedoneif [  "$cal"  ==  "+"  ];then         echo  $num 1  $cal   $num 2 = $ (($num 1+ $num 2) "elif [ " $cal " ==  "-"  ];then        echo  "$num 1  $cal   $num 2 =  $ (($num 1-$num 2)) "elif [ " $cal " == " * " ];then         echo  $num 1  $cal   $num 2 = $ (($num 1* $num 2) "elif [ " $cal "  ==  "/"  ];then        echo  "$num 1  $cal  $ num2 = $ (($num 1/$num 2)) "fiecho " already completed! thanks for your using! " 

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Simple script----Calculator for Linux Beginners