open(FILE, '<', 'file.txt');
# binmode(FILE,":utf8");
my $content; { local $/; $content = <FILE>; }
close(FILE);

# binmode(STDOUT,":utf8");

use Data::Dumper;
use HTML::Entities;

print "Content-Type: text/html; encoding=utf-8\n\n";

local $Data::Dumper::Useqq = 1;
print '<pre>';
print encode_entities(Dumper($content));
print '</pre>';
print $content;

##</code><code>##

$VAR1 = "f\303\266\303\266\n";

föö

##</code><code>##

open(FILE, '<', 'file.txt');
binmode(FILE,":utf8");
my $content; { local $/; $content = <FILE>; }
close(FILE);

binmode(STDOUT,":utf8");

use Data::Dumper;
use HTML::Entities;

print "Content-Type: text/html; encoding=utf-8\n\n";

local $Data::Dumper::Useqq = 1;
print '<pre>';
print encode_entities(Dumper($content));
print '</pre>';
print $content;

##</code><code>##

$VAR1 = "f\x{f6}\x{f6}\n";

föö

##</code><code>##

open(FILE,"<:utf8", "$file");
binmode(FILE);