href="actions-file.html">actions files</a> and <a href="filter-file.html">filter file</a>, through the
      <a href="http://www.pcre.org/" target="_top">PCRE</a> and <span class="APPLICATION">PCRS</span> libraries.</p>
      <p>If you are reading this, you probably don't understand what <span class="QUOTE">"regular expressions"</span>
      are, or what they can do. So this will be a very brief introduction only. A full explanation would require a
      <a href="http://www.oreilly.com/catalog/regex/" targe