#!/bin/sh

echo "Please talk to me ..."
while :
do
  read INPUT_STRING
  case $INPUT_STRING in
        hello)
                echo "Hello yourself!"
                ;;
        bye)
                echo "See you again!"
                break
                ;;
        *)
                echo "Sorry, I don't understand"
                ;;
  esac
done
echo 
echo "That's all folks!"