I am using this bit of code to identify certain links within my content and swap them for another link.

PHP Code:
$re1='(\\[url\\])';    # Square Braces 1
$re2='.*';    # Non-greedy match on filler
$articleContent .=preg_replace("/".$re1.$re2.$re3."/i"'<a href="http://www.lesson-ology.com/content.php?whereto=416">Sign Up For Access</a>'$resource[1]); 
The problem with it is that it replaces everything between the tags what I want to do is replace ONLY the url and leave the rest intact.

What would the reg_ex look like to accomplish this?