Shell Script Convert Fahrenheit to Celsius Temperature ( Celsius to Fahrenheit Temperature )

#!/bin/bash
# Shell script to convert Fahrenheit to Celsius Temperature or Celsius 
# to Fahrenheit Temperature
# -------------------------------------------------------------------------
# Copyright (c) 2005 nixCraft project <http://cyberciti.biz/fb/>
# This script is licensed under GNU GPL version 2.0 or above
# -------------------------------------------------------------------------
# This script is part of nixCraft shell script collection (NSSC)
# Visit http://bash.cyberciti.biz/ for more information.
# -------------------------------------------------------------------------
# Fahrenheit and Celsius Temperature Scales more info:
# http://en.wikipedia.org/wiki/Temperature_conversion_formulas
# --------------------------------------------------------------------
echo "*** Converting between the different temperature scales ***"
echo "1. Convert Celsius temperature into Fahrenheit"
echo "2. Convert Fahrenheit temperatures into Celsius"
echo -n "Select your choice (1-2) : "
read choice
 
if [ $choice -eq 1 ]
then
	echo -n "Enter temperature (C) : "
	read tc
	# formula Tf=(9/5)*Tc+32
	tf=$(echo "scale=2;((9/5) * $tc) + 32" |bc)
	echo "$tc C = $tf F"
elif [ $choice -eq 2 ]
then
	echo -n "Enter temperature (F) : "
	read tf
	# formula Tc=(5/9)*(Tf-32) 
	tc=$(echo "scale=2;(5/9)*($tf-32)"|bc)
	echo "$tf = $tc"
else
	echo "Please select 1 or 2 only"
	exit 1
fi