#!/usr/bin/perl  -- 

use strict;
use warnings;

use URI;

my $base = 'http://foobert.org/dir/odir';
my $file  = 'foo.html';
my $uri = URI->new($base);

local $\=$/;
print $uri->path_segments( $uri->path_segments, $file );
print $uri;
print $uri->host('I-RTFM.org');
print $uri;

__END__
dirodir
http://foobert.org/dir/odir/foo.html
foobert.org
http://I-RTFM.org/dir/odir/foo.html