$ext="i_am_the_walrus.txt";
$ext=~s/^[^.]*(\.[\w]+$)/$1/;
print $ext;
##</code><code>##

use strict;
my $filename="you_are_the_whale.doc";
my $separator=".";
unless (($where=index($filename,$seperator) == -1) {
  my $ext=substr($filename,$where);
  print $ext;
} else {
  print "No extensions in the zoo.\n"; }

##</code><code>##

use strict;
use File::Basename;
my $filename="we_are_not_all_mammals.zoo";
my ($base, $directory, $ext)=fileparse($filename, '\.[\w]+$');
print $ext;