#!/usr/bin/perl

use strict;
use warnings;

use CGI;

my $cgi = CGI->new;
my $p = $cgi->param('test');

print $cgi->header,
  $cgi->start_html;

if (defined $p && length $p) {
  print $cgi->p(
    qq/test ist: "$p"/, $cgi->br,
    'das ist in Hex: ', unpack("H*", $p)
  );
}
else {
  print $cgi->start_form, 
    'test: ', $cgi->textfield(-name => 'test'), 
    $cgi->submit,
    $cgi->end_form;
}

print $cgi->end_html;