Regex to match an IP address that is embedded inside of another string

adamZ88 has asked for the wisdom of the Perl Monks concerning the following question:

Hello Monks, I am working with SNMP and perl. I am walking oid ipNetToMediaPhysAddress oid. The results always vary, but follow the following format nn.ooo.ooo.ooo.ooo:mmm. Here is an actual example of the result of walking that oid: 258.10.73.138.11:00 00 00 00 00 00. nn=is a variable length numeric string oo is an octet(decimal from 0 - 255) mm is a hex string

I want to compare a string containing an ip address to the results of this walk for an exact match to the "oo" values, I do not care about the rest of the values. For, example I want to check if "10.73.138.11" is equal to 258.10.73.138.11:00 00 00 00 00 00. I guess a different way to explain it is I want to check if the result contains the exact IP address that I need to inquire about. Here is my code so far:

(@arpResults) = &snmpwalk("$secret\@$gw", "$ipNetToMediaPhysAddress");
foreach $linebuf (@arpResults) {
if ($linebuf =~ /\d+\.$oc1\.$oc2\.$oc3\.$oc4\:*/){
print "$linebuf\n";
my $val;
   ($arpMib, $arpOctetstr) = split(/:/, $linebuf, 2);
   ($distIndex) = split (/\./,$arpMib, 2);
    map { $val .= sprintf("%02x",$_) } unpack "CCCCCC", $arpOctetstr;
    $macFromARP= uc (join(":",unpack("a2 a2 a2 a2 a2 a2",$val)));
    ($ifNamez)=&snmpget("$secret\@$gw", "$ifName\.$distIndex");
    $vlan = $ifNamez; $vlan =~ s/\D//g;
    print "$arpMib; $distIndex:$ifNamez:-$vlan   Value=\t$macFromARP\n
+";
}}
[download]

This is not working out for me because it still matches ips that have a forth octet begining with "11". Help is greatly appreciated.

Comment on Regex to match an IP address that is embedded inside of another string Download Code

Replies are listed 'Best First'.
Re: Regex to match an IP address that is embedded inside of another string by stevieb (Canon) on Apr 19, 2016 at 22:04 UTC
Is the colon always going to be in place after the last octet? With `/\d+\.$oc1\.$oc2\.$oc3\.$oc4\:/`, first, you don't need to escape the colon, and second, you use ``, so that means 0 or more. That means that it'll ignore the colon if it means a longer match. The following will match the 4th octet exactly before the colon, or it won't match at all: `/\d+\.$oc1\.$oc2\.$oc3\.$oc4:/`	[reply] [d/l] [select]
Re: Regex to match an IP address that is embedded inside of another string by GrandFather (Saint) on Apr 19, 2016 at 22:05 UTC
Take a look at Regular expression anchors. In particular \b. Premature optimization is the root of all job security	[reply]
Re^2: Regex to match an IP address that is embedded inside of another string by adamZ88 (Beadle) on Apr 19, 2016 at 22:13 UTC
Thank you for your prompt response. The colon and other hex characters will always follow the last octet. I Tried your suggestion, and it still matches other ips that begin the same way on the fourth octet. Here is how I modified my code `if ($linebuf =~ /\d+\.$oc1\.$oc2\.$oc3\.$oc4:*/`	[reply] [d/l]
Re^3: Regex to match an IP address that is embedded inside of another string by stevieb (Canon) on Apr 19, 2016 at 22:30 UTC
As I stated in my above post, you need to get rid of the `*`.	[reply] [d/l]
Re^4: Regex to match an IP address that is embedded inside of another string by adamZ88 (Beadle) on Apr 20, 2016 at 13:17 UTC
Re^2: Regex to match an IP address that is embedded inside of another string by adamZ88 (Beadle) on Apr 19, 2016 at 22:26 UTC
Will do, Thank you.	[reply]
Re: Regex to match an IP address that is embedded inside of another string by Anonymous Monk on Apr 19, 2016 at 22:11 UTC
`#!/usr/bin/perl use strict; use warnings; print my $lookfor = '10.73.138.11', "\n\n"; print /\b\Q$lookfor\E\b/ ? "matches $_\n" : "fails $_\n" for qw( 110.73.138.11 10.73.138.11 10.73.138.111 10.735138.11 );` [download]	[reply] [d/l]