/[^[:print:]]/;
[download]

You could use the POSIX [:print:] character class. Or, rather, its inverse.

if ($string =~ /[^[:print:]]/) {
  print "Found unprintable characters\n";
}
[download]

use POSIX;

for ("foo; is ok", "foo\x3") {
  if (/[^[:print:]]/) {
    print "Contains unprintables\n";
  }
  else {
    print "$_ is safe\n";
  }
}
[download]

Despite the name, you don't need to use the POSIX module in order to use POSIX character classes.

--
<http://dave.org.uk>

"The first rule of Perl club is you do not talk about Perl club."
-- Chip Salzenberg

Or, use a named parameter regex.

my $string = "\x07\x1b\x04Safe \x12to print\x03.\n";
$string =~ s/\P{Print}//g;
print $string if length $string;
[download]