use strict;
use warnings;

my $dataStart = tell DATA;

print while <DATA>;

open my $clobber, '>', $0;
seek $clobber, $dataStart, 0;
print $clobber "Clobbered\n";
close $clobber;

seek DATA, $dataStart, 0;
print while <DATA>;

__DATA__
Original contents

##</code><code>##

Original contents
Clobbered