While it's generally handy if you show some example input, in this case your question is "why is $2 set?" which doesn't need sample input. The answer is because it's the second parenthesised value in the regexp. Perl's REs never compress the list of found values in case knowing which one is which is important. In this case, a simplification will get you what you want:
This way, there is only one set of capturing parens. The first set of parens has the ?: modifier which says "this is for grouping only, not for capturing."
Are you posting in the right place? Check out Where do I post X? to know for sure.
Posts may use any of the Perl Monks Approved HTML tags. Currently these include the following:
<code> <a> <b> <big>
<blockquote> <br /> <dd>
<dl> <dt> <em> <font>
<h1> <h2> <h3> <h4>
<h5> <h6> <hr /> <i>
<li> <nbsp> <ol> <p>
<small> <strike> <strong>
<sub> <sup> <table>
<td> <th> <tr> <tt>
Snippets of code should be wrapped in
<code> tags not
<pre> tags. In fact, <pre>
tags should generally be avoided. If they must
be used, extreme care should be
taken to ensure that their contents do not
have long lines (<70 chars), in order to prevent
horizontal scrolling (and possible janitor
Want more info? How to link or
or How to display code and escape characters
are good places to start.