The close keyword

The function close closes the file or pipe associated with FILEHANDLE, flushes the I/O buffers, and closes the system file descriptor. Returns true, if all operations succeed and if no error was reported by any PerlIO layer. Closes the currently selected FILEHANDLE, if the argument is omitted.

As an open will close the FILEHANDLE, it is not necessary to close the FILEHANDLE in this case, although an explicit close on an input file resets the file counter ($.).

  close FILEHANDLE
  close

  use open IN  => ":crlf", OUT => ":bytes";
  […]
  use open IO  => ":encoding(iso-8859-7)";