#!/usr/bin/env perl

my $string = do {
    open my $fh, '<', $0 or die "Cannot open $0: $!\n";
    local $/ = undef;
    <$fh>;
};

if ($string =~ m/^__END__\n/gm) {
    print '__END__ tag found at ', pos($string), "\n";
}
print 'Entire file length: ', length($string), "\n";

END { print 'DATA filehandle tell offset: ', tell(DATA), "\n"; }

__END__
Now is the time for all good men to come to the aid of their country.
Now is the time for all good men to come to the aid of their country.
Now is the time for all good men to come to the aid of their country.
Now is the time for all good men to come to the aid of their country.
Now is the time for all good men to come to the aid of their country.
Now is the time for all good men to come to the aid of their country.
Now is the time for all good men to come to the aid of their country.
Now is the time for all good men to come to the aid of their country.
Now is the time for all good men to come to the aid of their country.
Now is the time for all good men to come to the aid of their country.
Now is the time for all good men to come to the aid of their country.
Now is the time for all good men to come to the aid of their country.
Now is the time for all good men to come to the aid of their country.
Now is the time for all good men to come to the aid of their country.
Now is the time for all good men to come to the aid of their country.
Now is the time for all good men to come to the aid of their country.
Now is the time for all good men to come to the aid of their country.
Now is the time for all good men to come to the aid of their country.
Now is the time for all good men to come to the aid of their country.
Now is the time for all good men to come to the aid of their country.
Now is the time for all good men to come to the aid of their country.
Now is the time for all good men to come to the aid of their country.

##</code><code>##

__END__ tag found at 351
Entire file length: 1892
DATA filehandle tell offset: 351