here is a small tool for someone learning to use regular expressions. it's very basic, and allows you to try different patterns and combinations. I made it to help me, because I like to try different things, to get a good understanding of how things work.

<?php
$search = isset($_POST['search'])?$_POST['search']:"//";
$match = isset($_POST['match'])?$_POST['match']:"<>";

echo '<form method="post">';
echo 's: <input style="width:400px;" name="search" type="text" value="'.$search.'" /><br />';
echo 'm:<input style="width:400px;" name="match" type="text" value="'.$match.'" /><input type="submit" value="go" /></form><br />';
if (preg_match($search, $match)){echo "matches";}else{echo "no match";}
?>