my $string = q/This is a test./;
my $regex1 = qr(\bis);
my $regex2 = qr(is);
print $string =~ /$regex1/g, "\n";
print $string =~ /$regex2/g, "\n";
# prints
is
isis

##</code><code>##

$ip = qr("192.168.3.5");

##</code><code>##

my $ip = "192.168.3.5";
$ip = quotemeta $ip;