Menu Driven Shell Script

A menu driven Shell script which has following options
# Contents of /etc/passwd
# List of users currently logged
# Prsent handling directory
# Exit
# As per option do the job
# -----------------------------------------------
# Copyright (c) 2005 nixCraft project
# 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.
# -------------------------------------------------------------------------

while :
do
clear
echo " M A I N - M E N U"
echo "1. Contents of /etc/passwd"
echo "2. List of users currently logged"
echo "3. Prsent handling directory"
echo "4. Exit"
echo -n "Please enter option [1 - 4]"
read opt
case $opt in
1) echo "************ Conents of /etc/passwd *************";
more /etc/passwd;;
2) echo "*********** List of users currently logged";
who | more;;
3) echo "You are in $(pwd) directory";
echo "Press [enter] key to continue. . .";
read enterKey;;
4) echo "Bye $USER";
exit 1;;
*) echo "$opt is an invaild option. Please select option between 1-4 only";
echo "Press [enter] key to continue. . .";
read enterKey;;
esac
done