#!c:/perl/bin/perl.exe

use Data::Dumper;
use strict;
use warnings;

my $string = qq(foo\nbar\n);

open my $fh, '>', "dos.txt";
my @layers = PerlIO::get_layers($fh, output => 1); # edit
print Dumper(\@layers);
print $fh $string;
close $fh;

open $fh, '>:pop', "unix.txt";
@layers = PerlIO::get_layers($fh, output => 1);
print Dumper(\@layers);
print $fh $string;
close $fh;

__END__

$VAR1 = [
          'unix',
          'crlf'
        ];

$VAR1 = 'unix';

$ hexdump.exe -c  dos.txt
0000000   f   o   o  \r  \n   b   a   r  \r  \n
000000a


$ hexdump.exe -c  unix.txt
0000000   f   o   o  \n   b   a   r  \n
0000008