How to handle encodings on input/output

using character encodings

open my $handle, '<:encoding(UTF-8)', $file;
open my $handle, '<:encoding(iso-8859-1)', $file;

open my $handle, '<', $file;
binmode $handle, ':encoding(UTF-8)';

use open ':encoding(UTF-8)';
use open ':encoding(iso-8859-1)';
use open ':locale';

use PerlIO::locale;
binmode STDOUT, ':locale';

# see http://perlgeek.de/en/article/encodings-and-unicode
# see http://www.perl.com/pub/2012/04/perlunicook-standard-preamble.html