#! /usr/bin/perl
use strict;
use warnings;
use CGI;

my $lost_file = "/FULL/path/to/lost.txt";
my $cgi = CGI->new;

open LOST, '>>', $lostfile or die "open(>>) $lostfile failed: $!\n";

for my $param ( $cgi->param ) {
  print LOST "$param ", $cgi->param($param), "+";
}
print LOST "\n";

print $cgi->header('text/plain'),
  "job is done.\n";