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;
[download]

gives me:

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

föö
[download]

(when viewed in encoding=utf-8)

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;
[download]

gave me:

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

föö
[download]

(but I needed to set encoding=utf-8 manually on this one, was western before..)

The bad news is: setting the input filehandle and the stdout to :utf8 in my more complex script gives no positive change. Is that an indicator that the string gets "compromised" with non-utf8 somewhere in between? Any ideas?

UPDATE: Solved! Woa! Got it!! Was a stupid error:

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

Joost's hint "never set the :raw layer (i.e. use binmode(FILEHANDLE) - without a second argument)" in mind I could spot this double-declaration in my code. The problem is always in front of the screen...

Nevertheless, should it be $VAR1 = "f\303\266\303\266\n"; or $VAR1 = "f\x{f6}\x{f6}\n"; for proper utf8 output? (the latter, right?)