#!/usr/bin/perl -w

use strict;

use IO::File;
use PerlIO;
use Data::Dumper;

my $fname = 'big.txt';

my $fh = IO::File->new($fname, O_RDONLY, ":utf8")
  or die "cannot open $fname :: $!";

STDERR->print(Dumper([PerlIO::get_layers($fh)]));

$fh->close();