Hello Tiarcon, and welcome to the Monastery!

Just letting you know that you don’t have to use regular expressions for this. has dedicated modules for reading email. For example:

#! perl
use strict;
use warnings;
use Email::Simple;

my $file = 'YourEmailHere.eml';

open(my $fh, '<', $file)
    or die "Cannot open file '$file' for reading: $!";

my $text = do { local $/; <$fh>; };

close $fh
    or die "Cannot close file '$file': $!";

my $email   = Email::Simple->new($text);
my $from    = $email->header('From');
my $subject = $email->header('Subject');

print "FROM:    $from\n";
print "SUBJECT: $subject\n";
[download]

See Email::Simple.

Hope that helps,