my $rec_format = 'a4a5a1'; my $rec_size = 10; binmode $fh_out, ':encoding(UTF-8)'; print $fh_out pack($rec_format, @fields); ... binmode $fh_in, ':encoding(UTF-8)'; read($fh_in, my $rec = '', $rec_size); @fields = unpack($rec_format, $rec);