use strict;
use warnings;

my $src_enc = 'UTF-8';
my $dst_enc = '...';

binmode(STDIN,  ":encoding($src_enc)");
binmode(STDOUT, ":encoding($dst_enc)");

print while <STDIN>;

##</code><code>##

use strict;
use warnings;

use Encode qw( from_to );

my $src_enc = 'UTF-8';
my $dst_enc = '...';

while (<>) {
   from_to($_, $src_enc, $dst_enc);
   print;
}