#!/bin/sh

# Using bc for math,
# calculates sales tax.

echo -n "Please enter the amount of purchase: "
read amount
echo

echo -n "Please enter the total sales tax rate: "
read rate
echo 

result=$( echo "
scale=2; tax=$amount*$rate/100.00;total=$amount+tax;print total" | bc )

if [ $( expr "$result > 200" ) ]
then
    echo You could qualify for a special free shipping rate.
    echo -n Do you want to? "(yes or no) "
    read shipping_response
    if [ $shipping_response -eq "yes" ]
    then
        echo "Free shipping selected."
    fi
fi

echo "The total with sales tax = \$ $result."
echo "Thank you for shopping with the Bourne Shell."