Perl regular expression to match IP address

Question

I wrote this code, but it does not work. Can someone point out a problem?

sub match_ip() { my $ip = "The IP address is 216.108.225.236:60099"; if($ip =~ /(\d{1-3}\.\d{1-3}\.\d{1-3}\.\d{1-3}\:\d{1-5})/) { print "$1\n"; } } 

EDIT: I just wanted to extract the IP address and not perform any checks.

Answer 1

Change {1-3} to {1,3} the same for {1-5} → {1,5}

Answer 2

In the spirit of TIMTOWTDI, there is one more thing here: Regexp::Common::net part of Regexp::Common may have the regular expression that you want.

Answer 3

Alternatively, you can use Data::Validate::IP with the caution that it does not recognize the port, so you will need to split into :

 use strict; use warnings; use Data::Validate::IP; my $ip_with_port="216.108.225.236:60099"; my $ip=(split /:/,$ip_with_port)[0]; my $validator=Data::Validate::IP->new; if($validator->is_ipv4($ip)) { print "Yep, $ip is a valid IPv4 address.\n"; } else { print "Nope, $ip is not a valid IPv4 address.\n"; } 

Output:

 Yep, 216.108.225.236 is a valid IPv4 address. 

Answer 4

Replace the dash with commas.

 /(\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}\:\d{1,5})/ 

Answer 5

Although CPAN has well-documented and tested modules for mapping and checking IP addresses, there should be no good reason for you. Personally, I never had a real reason to use them for verification purposes, since I trusted / served the input.

Here is a shorter version of your regexp with your own traps:

 while (my $ip = <DATA>) { chomp $ip; # older version # if($ip =~ /(\d{1-3}\.\d{1-3}\.\d{1-3}\.\d{1-3}\:\d{1-5})/) # see below for explanation if ($ip =~ /\b(\d{1,3}(?:\.\d{1,3}){3}:\d{1,5})\b/) { print "$ip - matches\n"; } else { print "$ip - does not match\n"; } } __DATA__ 216.108.225.236:60099 4.2.2.1:1 216.108.225.236:0 1216.1108.1225.1236:1234 216.108.225.236x:123 9216.108.225.236:8472 10.10.10.10 

Results:

 216.108.225.236:60099 - matches 4.2.2.1:1 - matches 216.108.225.236:0 - matches 1216.1108.1225.1236:1234 - does not match 216.108.225.236x:123 - does not match 9216.108.225.236:8472 - does not match 10.10.10.10 - does not match 

Explanation:

 /\b # word boundary ( # start memory capture group 1 \d{1,3} # one to three digits, first octat (:? # start non memory capture group, notice ?: \.\d{1,3} # a literal dot followed by an ip octet ) # end non memory capture group {3} # three times of dots and ip octets : # match a colon \d{1,5} # port number, one to five digits ) # end of memory capture group 1 \b # word boundary 

Hope this helps.

Answer 6

This can help:

 my $ip = "195.249.61.14"; my @ips = ( "set protocols bgp group IBGP-RRCL-CUSTOMER neighbor 195.249.61.142", "set protocols bgp group IBGP-RRCL-CUSTOMER neighbor 195.249.61.14", "set protocols bgp group IBGP-RRCL-CUSTOMER neighbor 195.249.61.141" ); foreach (@ips) { print "$_\n" if ( /\b$ip\b/ ); } 

Output:

 set protocols bgp group IBGP-RRCL-CUSTOMER neighbor 195.249.61.14 

Answer 7

http://metacpan.org/pod/Regexp::Common::net

If you retrieve an IP address that is not an IP address, you are not retrieving the right things.

Answer 8

 #!/usr/bin/perl $str = 'IP address is : 70.21.311.105'; if ($str =~ m/(\d{1,3})\.(\d{1,3})\.(\d{1,3})\.(\d{1,3})/) { if ($1 <= 255 && $2 <= 255 && $3 <= 255 && $4 <= 255 ) { print "Valid $str\n"; } else { print "invalid IP $str\n"; } } __END__ 

Answer 9

Try the following:

 $variablename=~m/((((0-9)|((1-9)(0-9))|(1([0-9]){2})|(2[0-4][0-9])|(2[5][0-5]))\.){3})((0-9)|((1-9)(0-9))|(1([0-9]){2})|(2[0-4][0-9])|(25[0-5]))/) 

Answer 10

 use strict; use warnings; open(FH,"<fileName.txt") or die "file not found ,$_"; while(my $line=<FH>) { push(my @arr,($line)); foreach my $arrVal (@arr) { if($arrVal=~/IPv4 Address(?=.*\b((25[0-5]|2[0-4]\d|[0-1]?\d?\d)(\.(25[0-5]|2 [0-4]\d|[0-1]?\d?\d)){3})\b)/) { print "$arrVal\n"; } } 

Answer 11

You can also use the following regular expression to make sure that the square is no more than 255, it also “repeats” the comparison of digits instead of copying it 4 times.

 my $rx = qr/^(?!(\.))(\.?(\d{1,3})(?(?{$^N > 255})(*FAIL))){4}$/; if('192.168.1.2' =~ $rx){ print "OK\n"; } 

It uses several functions from the perl regex matching (man perlre):

• (* FAIL): stops matching pattern and does not work
• (? (condition) ...): conditional match
• (? {code}): used in this state

Answer 12

 $ip = "10.255.256.1"; # will accept valid ips if ($ip =~ m/^([1|2][0-9]{1,2})\.([0-255]{1,3}\.){2}[0-255]{1,3}/ && ($1 <=255)) { print "This is a valid ip: $ip \n"; } else { print "This is not a valid ip: $ip \n"; }