#!/usr/bin/perl
# illustrates simple pattern mattching 

#  () group pattern elements. 
#  * : preceding character, element, or group of elements may occur 0,1,..times
#  + the preceding element or group of elements must occur at least once. 
#  ? matches zero or one times.

$s = 'One if by land and two if by sea';
$x = "lamp";
print $s "\n"; 

if ($s =~ /if by la/) {print "YES \n"} else {print "NO \n"}
if ($s =~ /one/)      {print "YES \n"} else {print "NO \n"}
if ($s =~ /one/i)     {print "YES \n"} else {print "NO \n"}
if ($x =~ /l.mp/)     {print "YES \n"} else {print "NO \n"}
if ($x =~ /l?mp/)     {print "YES \n"} else {print "NO \n"}