t following __END__
    ERROR          - we are in big trouble, probably not a perl script</code></pre>

<p>Most applications will be only interested in lines of type <b>CODE</b>. For another example, let&#39;s write a program which checks for one of the so-called <i>naughty matching variables</i> <code>&amp;`</code>, <code>$&amp;</code>, and <code>$&#39;</code>, which can slow down processing. Here is a <b>write_line</b>, from the example program <b>find_naughty.pl</b>, which does that:</p>

<pre><code> su