its a thing about patterns, for a start...
if you want a web-crawler, that goes thru all your sites you need to find the links on a page
typical link on a page :
...............:<a href="http://www.something.com/index.php?dhjkfhkadgfhj">link</a>
Important: -------------------------------------------------
pattern for that would be :
its starting with "a href" and i need all that is between the "....",
#a href="(.*)"#
you need the () to define what to keep or what to change
the fun starts with this ...a title="" href=""
...
i think regular expressions are on the best thing ever invented, you should really try it out ....