#!/usr/local/bin/perl -Tw
       use CGI ':standard';
       $file = param('file');
       $comment = param('comment');
       unless ($file) { $file = 'xcanalys.txt'; }
       unless ($comment) { $comment = 'No comment'; }
       open (OUTPUT, ">>./" . $file) or die "$!";
       print OUTPUT $comment . "\n";
       close OUTPUT;
       print header, start_html;
       print "<P>Thanks!</P>\n";       
       print end_html;
1;

##</code><code>##

perl -T tainttest.pl
(offline mode: enter name=value pairs on standard input)
^Z