Why these are the very principles which powers TheDamian's minion selfGOL (well those and pure unrelenting evil ;) If you've got your permissions setup correctly then to change your script within the script can just be a simple combination of open and exec e.g

print "am in $0\n";

{
  local $/;

  seek DATA, 0, 0;

  (my $data = <DATA>) =~ s/\bexec\b.*\n//;

  open(ME, ">$0") or die("ack - $!");

  print ME qq[print "am in new \$0\\n";\n], $data;

  close ME;

}

exec "perl $0";

__DATA__
[download]

HTH

_________
broquaint