#!/usr/bin/env perl

use strict;
use warnings;
use FindBin qw($Bin);
use File::Spec::Functions qw(catfile);
use File::ReadBackwards;

my $bw = File::ReadBackwards->new(catfile($Bin,$0))
    or die "Can't read $0: $!\n";

while( defined(my $line = $bw->readline) ) {
    last if $line =~ m/^__(?:END|DATA)__/;
    print $line;
}

__DATA__
1234
5678
9ABC
DEFG