Hi perl monks, I wrote a script to perform the following task. It grabs the ACKs lines from the dhcp log file using tail. It takes the ip of the recently connected device and performs a snmp query. Then it will append this info to a plain text record. So far it is working, here is the code: 
#!/usr/bin/perl -w
use strict;
use File::Tail;
use Cwd qw();

my $path = Cwd::cwd();
my $community = 'public';
my $snmp_bsid = '.1.3.6.1.4.1.2700.1.1.11.0';
my $bsid;

my $file = File::Tail->new(
        name =>'/var/log/messages', 
        interval => 1, 
        maxinterval => 1, 
        resetafter=> 5, 
        );

while (defined(my $line=$file->read)) {
         print $line,"\n"; 
                if ($line =~ /^(.*) dns02cor dhcpd: DHCPACK on ([0-9\.
+]+) to ([[:xdigit:]:]+).* ([0-9\.]+)/) {
                        write_register($1,$2,$3);
            }

}

sub write_register {
    my ($date,$client_ip,$client_imsi) = @_;

    $output=qx(snmpget -v2c -t1 -c $community $client_ip $snmp_bsid 2>
+&1);
    my @result=split(/:/,$output);
       if ($result[3]){
        $bsid=$result[3];
        $bsid=~s/ //g;
        $bsid=~s/\n//g;
    }

        system 'echo "'.$date.','.$client_ip.','.$client_imsi.','.$bsi
+d.'," >>'.$path.'/register_list.txt';
    
}

1;

[download]
The weird thing is when I list the output register: Take a look: Apr 12 20:56:54,186.183.101.72,77:10:00:02:06:85,77777851CFC7106,
Apr 12 20:57:06,186.183.104.175,77:10:00:03:38:56,,
Apr 12 20:57:08,186.183.106.13,77:10:00:01:92:00,77777851CFC8901,
Apr 12 20:57:11,186.183.101.196,77:10:00:01:99:35,,
Apr 12 20:57:11,186.183.105.204,77:10:00:01:93:30,,77777851CFC9A02,

As you can see there are some empty bsid fields,but if I manually execute the snmpget query from the command line to those ips, I can bring the value without any problem. I would like to know if you have some suggestion for me in order to improve my scrip. I also think that due to the ACKs rate (4 or 5 per secs)I should consider implementing some fork technique ... well. I hope to hear your opinions, Regards, Leandro.

In reply to snmpget is missing some values by leostereo

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