Case Control in Shell Script

In C programming language you have seen that switch-case is used to perform a set of operations based on some values. In a shell script, a similar type of logic can be implemented by using a case. In the following example, we have shown how the case works.

To run this script, we have to pass three arguments, such as 10 + 7.

Basic Calculator

#!/bin/bash if test $# = 3 then case $2 in +) let z=$1+$3;; -) let z=$1-$3;; /) let z=$1/$3;; x|X) let z=$1*$3;; *) echo Warning - $2 is invalid operator exit;; esac echo The result is $z else echo "Usage - $0 first_value operator second_value" echo " Where, first_value and second_value are numeric values" echo " and the operator is either +, -, x or /" fi

CBasic alculator using `expr`

echo "Enter the first number" read a echo "Enter the second number" read b echo "Enter the operator:" echo -e "Addition: +\nSubtraction: -\nMultiplication: x\nDivision: /" read op case $op in +) c=`expr $a + $b` echo "Sum of $a and $b is $c";; -) c=`expr $a - $b` echo "Difference of $a and $b is $c";; x) c=`expr $a \* $b` echo "Product of $a and $b is $c";; /) c=`expr $a / $b` echo "Division of $a and $b is $c";; *) echo "Invalid Operator" exit;; esac

Happy Exploring!