#!/usr/bin/perl
use strict;
use warnings;

use HTML::Entities;

$_ = "\0foo\tbar\tbaz\r\n\a";

tr/\x00-\x1f\x7f/\x{2400}-\x{241f}\x{2421}/;
print encode_entities $_;

__END__
␀foo␉bar␉baz␍␊␇