use strict;
my $str = 'Valid
1.2.3.4
255.255.255.255
1.2.3.4-1.2.3.4
1.2.3.4/24
1.2.3.4/8
www.example.com
www.example.lv
www.example.com
Invalid
1.2.3
1.2.3.
.1.2.3
1.2.3.4/33
www.-example.com
1.2.3.4-1.2.3.256
1.2.3.4.5.6.7.8 (use anchors ^ and $ to skip these if needed)
999.999.999.999 (use a complex regex to skip these if needed)
299.299.299.299
001.002.003.004 (these use octal notation, not decimal)
';
my $regex = qr/^(?:(?:(?:25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[1-9]?[0-9])\.){3}(?:25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[1-9]?[0-9])(?:-(?:(?:25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[1-9]?[0-9])\.){3}(?:25[0-5]|2[0-4][0-9]|1[0-9][0-9]|[1-9]?[0-9])|\/(?:[0-9]|[1-2][0-9]|3[0-2]))?|(?:[a-z0-9]+(?:-[a-z0-9]+)*\.)+[a-z]{2,})$/mp;
if ( $str =~ /$regex/g ) {
print "Whole match is ${^MATCH} and its start/end positions can be obtained via \$-[0] and \$+[0]\n";
# print "Capture Group 1 is $1 and its start/end positions can be obtained via \$-[1] and \$+[1]\n";
# print "Capture Group 2 is $2 ... and so on\n";
}
# ${^POSTMATCH} and ${^PREMATCH} are also available with the use of '/p'
# Named capture groups can be called via $+{name}
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for Perl, please visit: http://perldoc.perl.org/perlre.html