CODEWITHSUNDEEP
regexperl
Kerby82
Kerby82

Reputation: 5146

perl regular expression extract ip from router show output

I have this output from router command:

Interface              IP-Address      OK? Method Status                Protocol
POS0/0/0               10.137.99.2    YES NVRAM  up                    up

I want to find a regular expression to identify the IP-Address:

I tried with:

if ( $_ =~ m/(.*?)\s*?(.*?)\s*?(.*?)\s*?(.*)/i ){
    #print "$1->$2\n";
    $sources{$2}=$1;
}

and then use $2 as ip.

However, it does not work; where am I wrong?

Upvotes: 1

Views: 1067

Answers (5)

Francisco R
Francisco R

Reputation: 4048

if ($_ =~ /\b(\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3})\b/)
{
        print "IP: $1\n";
}

If you just want to obtain the second column, then may be you should use split instead of regular expressions. To obtain field #2:

@field = split(/ +/, $_);
print "$field[1]";

Upvotes: 6

BadFileMagic
BadFileMagic

Reputation: 701

Since this is regularly formatted data, you could probably just use split: and get at it like this:

#!/usr/bin/env perl
use Modern::Perl;


my $buff = "Interface              IP-Address      OK? Method Status                Protocol
POS0/0/0               10.137.99.2    YES NVRAM  up                    up  ";

for my $line (split /\n/,$buff)
{
  next if $line =~ /^Interface/;
  my ($interface, $ip) = (split /\s+/,$line)[0,1];
  say "IP $ip is on Interface $interface";
}

which produces this output:

IP 10.137.99.2 is on Interface POS0/0/0

Upvotes: 2

Chowlett
Chowlett

Reputation: 46667

PacoRG's answer works nicely, but to explain where yours is going wrong:

Remember that * can match no occurrences. You're telling each group to match as little as possible, so the first 3 groups are capturing nothing. Further, you want to grab as many consecutive whitespace characters as possible, not as few.

Keeping with a RegEx somewhat like your original, you could use

m/(.+?)\s+(.+?)\s+(.+?)\s+(.+?)/i

Upvotes: 2

hsz
hsz

Reputation: 152206

Try with:

m/.*?(\d+\.\d+\.\d+\.\d+).*/i

Upvotes: 0

tchrist
tchrist

Reputation: 80384

The bug is all those minimal matches. Just use

($if, $ip) = split;
$sources{$ip} = $if;

Upvotes: 1

Related Questions