## from _read_record() in Tie::File
  { local $/ = $self->{recsep};
    my $fh = $self->{fh};
    $rec = <$fh>;
  }
...
    unless ($self->{rdonly}) {
      local $\ = "";
      my $fh = $self->{fh};
      print $fh $self->{recsep};
    }