#! /usr/bin/perl

use strict;
use warnings;
use Email::Simple;
use DBI;
use File::Copy;
use Date::Parse;
use DateTime;
use Path::Tiny qw(path);

[..]

open (MESSAGE, "< $ARGV[0]") || die "Couldn't open email $ARGV[0]\n";
       undef $/;
$raw_email = <>;
close MESSAGE;

my $mail            = Email::Simple->new($raw_email);
my $from_header     = $mail->header("From");
my $to_header       = $mail->header("To");
my $date_header     = $mail->header("Date");
my $aol_header      = $mail->header("Authentication-Results");

[...]