my $startCh = chr(0);
my $endCh = chr(31);

$text =~ s/[$startCh-$endCh]//g;

##</code><code>##

$startCh = chr(0);
$endCh = chr(9);

$text =~ s/[$startCh-$endCh]//g;

$startCh = chr(11);
$endCh = chr(31);

$text ==~ s/[$startCh-$endCh]//g;