against. Perl Compatible Regular Expressions are an especially convenient <span class=
      "QUOTE">"dialect"</span> of the regular expression language.</p>
      <p>To make a simple analogy, we do something similar when we use wild-card characters when listing files with the
      <b class="COMMAND">dir</b> command in DOS. <tt class="LITERAL">*.*</tt> matches all filenames. The <span class=
      "QUOTE">"special"</span> character here is the asterisk which matches any and all characters. We can be more
 