my $old_buffer;
my $offset = 0;
while (read(FH,65536,\$buffer)) {
  # Append the last 8 bytes of the buffer
  if ($old_buffer) {
    $buffer = substr( $old_buffer, -8 ) . $buffer;
    $offset -= 8;
  };
  if ($buffer =~ /(......\0\0\0........)/sm) {
    printf "Found possible candidate at %s : $1\n", $offset + pos;
  };
  $offset += len $buffer;
  $old_buffer = $buffer;
};