use warnings;
use strict;

use File::Edit::Portable;

my $rw = File::Edit::Portable->new;

my $recsep;

$recsep = $rw->recsep('unix.txt');
print "unix file before write: $recsep\n";

$recsep = $rw->recsep('win.txt');
print "win file before write: $recsep\n";

my $ufh = $rw->read(file => 'unix.txt');
my @unix_contents = <$ufh>;
close $ufh;

$rw->write(contents => \@unix_contents);
$recsep = $rw->recsep('unix.txt');
print "unix file after rewrite: $recsep\n";

my $wfh = $rw->read(file => 'win.txt');
my @win_contents = <$wfh>;
close $wfh;

$rw->write(contents => \@win_contents);
$recsep = $rw->recsep('win.txt');
print "win file after rewrite: $recsep\n";

##</code><code>##

# unix

$ ./find.pl

unix file before write: \0a
win file before write: \0d\0a
unix file after rewrite: \0a
win file after rewrite: \0d\0a

# windows

E:\test>perl find.pl

unix file before write: \0a
win file before write: \0d\0a
unix file after rewrite: \0a
win file after rewrite: \0d\0a

##</code><code>##

use File::Edit::Portable qw(pread pwrite);

my $fh = pread('file.txt');

# or even

my @contents = pread('file.txt');

# then, later

pwrite('file.txt', \@contents);