open(my $fh, '<:encoding(UTF-8)', $ARGV[0])
    or die("Can't open input file \"$ARGV[0]\": $!\n");
$_ = do { local $/; <$fh> };
s/([^\x0A\x20-\x7E])/ sprintf '<U+%04X>', $1 /eg;
print;

##</code><code>##

My name is <U+00C9>ric.
I don't speak <U+65E5><U+672C><U+8A9E>.