binmode $fh_in;
binmode $fh_out;

local $/ = \90;
while (<$fh_in>) {
   print $fh_out "$_\x0D\x0A";
}

##</code><code>##

binmode $fh_out;

while (length($str)) {
   my $rec = substr($str, 0, 90, '');
   print $fh_out "$rec\x0D\x0A";
}