Getting parts of a URL (Regex)

Question

Given the URL (single line):
http://test.example.com/dir/subdir/file.html

How can I extract the following parts using regular expressions:

1. The Subd

Answer 1

subdomain and domain are difficult because the subdomain can have several parts, as can the top level domain, http://sub1.sub2.domain.co.uk/

 the path without the file : http://[^/]+/((?:[^/]+/)*(?:[^/]+$)?)  
 the file : http://[^/]+/(?:[^/]+/)*((?:[^/.]+\.)+[^/.]+)$  
 the path with the file : http://[^/]+/(.*)  
 the URL without the path : (http://[^/]+/)  

(Markdown isn't very friendly to regexes)