This is an imperfect example of doing this via regexes.

#!/usr/bin/perl
use strict;
my @urls = qw(http://foo.com/downloads/pkg-5.6.tar.gz
http://bar.com/list/file-5.6-win32.zip
example.org/subd/golf.txt
http://digg.com/page4
http://www.cnn.com/2008/US/07/17/beck.che.guevara/index.html
);



for my $url (@urls){
   
   print STDERR "URL: $url\n";
   my $segment = url_segments($url);
   for my $key ( sort keys %$segment ){
      my $val = $segment->{$key};
      print STDERR " - $key : $val\n";
   }
   print STDERR "\n";
}


exit;





sub url_segments {
   my $url = shift;

   my %segment = ( 
      url => $url,
      domain => undef,
      location => undef,
      location_relative => undef,
      filename => undef,
      filename_only => undef,
      extension => undef,
      query_string => undef,
      protocol => undef,
   );
   
   if ( $url=~s/(\?.*)$// ) {# take out possible query string
      $segment{query_string}  = $1;
   }

   if ( $url=~s/^([a-z]{3,5})\:\/\///i ){
      $segment{protocol}      = $1;
   }

   if ( $url=~s/^([\w\.]+)// ){
      $segment{domain}        = $1;
   }
   
   
   


   if ( $url=~s/([^\/]+)\.([a-z0-9]{1,5})$// ){
      $segment{filename}      = "$1.$2";
      $segment{filename_only} = $1;
      $segment{extension}     = $2;
   }

   if ( $url ){
      $segment{location_relative} = $url;
      $segment{location} = $segment{domain}.$segment{location_relative
+};
   }
   
   return \%segment; 
}
[download]

# output:
URL: http://foo.com/downloads/pkg-5.6.tar.gz
 - domain : foo.com
 - extension : gz
 - filename : pkg-5.6.tar.gz
 - filename_only : pkg-5.6.tar
 - location : foo.com/downloads/
 - location_relative : /downloads/
 - protocol : http
 - query_string :
 - url : http://foo.com/downloads/pkg-5.6.tar.gz

URL: http://bar.com/list/file-5.6-win32.zip
 - domain : bar.com
 - extension : zip
 - filename : file-5.6-win32.zip
 - filename_only : file-5.6-win32
 - location : bar.com/list/
 - location_relative : /list/
 - protocol : http
 - query_string :
 - url : http://bar.com/list/file-5.6-win32.zip

URL: example.org/subd/golf.txt
 - domain : example.org
 - extension : txt
 - filename : golf.txt
 - filename_only : golf
 - location : example.org/subd/
 - location_relative : /subd/
 - protocol :
 - query_string :
 - url : example.org/subd/golf.txt

URL: http://digg.com/page4
 - domain : digg.com
 - extension :
 - filename :
 - filename_only :
 - location : digg.com/page4
 - location_relative : /page4
 - protocol : http
 - query_string :
 - url : http://digg.com/page4

URL: http://www.cnn.com/2008/US/07/17/beck.che.guevara/index.html
 - domain : www.cnn.com
 - extension : html
 - filename : index.html
 - filename_only : index
 - location : www.cnn.com/2008/US/07/17/beck.che.guevara/
 - location_relative : /2008/US/07/17/beck.che.guevara/
 - protocol : http
 - query_string :
 - url : http://www.cnn.com/2008/US/07/17/beck.che.guevara/index.html