Program runs fine once I learned the correct format for giving it permission and the syntax for running it from command line. I am a forgetful beginner.
#!/bin/bash
# Take user Input
echo "Enter Two numbers : "
read a
read b
# Input type of operation
echo "Enter Choice :"
echo "1. Addition"
echo "2. Subtraction"
echo "3. Multiplication"
echo "4. Division"
read ch
# Switch Case to perform
# calulator operations
case $ch in
1)res=`echo $a + $b | bc`
;;
2)res=`echo $a - $b | bc`
;;
3)res=`echo $a \* $b | bc`
;;
4)res=`echo "scale=2; $a / $b" | bc`
;;
esac
echo "Result : $res"