sub write_new_file {
    my ( $fn, $str ) = @_;

##</code><code>##

    my ($fn, $str_ref ) = @_;
# or $ref_str, $r_str or other possibilities

##</code><code>##

next if $name =~ /rev\d+\.config$/;
if ($name =~ /\.config$/) {blah..blah}