Re: grep ip address from dhcpd.leases file

A lease record may not contain a client-hostname, so your file parsing should accommodate that. DB suggestions have been provided. Perhaps the following parsing option, which would read the file in lease-record 'chunks' (via local $/ = 'lease';), will be a helpful start:

use strict;
use warnings;

local $/ = 'lease';

while (<DATA>) {
    my ($ip) = /\s+(\S+)\s+/ or next;
    my $client = /client-hostname\s+(".+")/ ? $1 : '';
    print "$ip,$client\n";
}

__DATA__
lease 192.168.20.4 {
    starts 6 2009/06/27 00:40:00;
    ends 6 2009/06/27 12:40:00;
    hardware ethernet 00:00:00:00:00:00;
    uid 00:00:00:00:00:00;
    client-hostname "examle-workstation1";
}

lease 192.168.20.5 {
    starts 6 2009/06/27 00:40:00;
    ends 6 2009/06/27 12:40:00;
    hardware ethernet 00:00:00:00:00:00;
}

lease 192.168.20.6 {
    starts 6 2009/06/27 00:40:00;
    ends 6 2009/06/27 12:40:00;
    hardware ethernet 00:00:00:00:00:01;
    uid 00:00:00:00:00:01;
    client-hostname "examle-workstation2";
}


lease 192.168.20.7 {
    starts 6 2009/06/27 00:40:00;
    ends 6 2009/06/27 12:40:00;
    hardware ethernet 01:00:00:00:00:00;
}
[download]

Output:

192.168.20.4,"examle-workstation1"
192.168.20.5,
192.168.20.6,"examle-workstation2"
192.168.20.7,
[download]

Comment on Re: grep ip address from dhcpd.leases file Select or Download Code

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Re^2: grep ip address from dhcpd.leases file by varalaxmibbnl (Acolyte) on Dec 15, 2013 at 07:40 UTC
thanks for the reply..if i want to take the present ip address which are entering into that dhcp.leases then is there any module to do that...thanks in advance..	[reply]
Re^3: grep ip address from dhcpd.leases file by Kenosis (Priest) on Dec 15, 2013 at 17:22 UTC
Provided you have read permissions for dhcp.leases, just use that file as your data source in the above script: `use strict; use warnings; local $/ = 'lease'; my $leaseFile = '/var/lib/dhcp3/dhcpd.leases'; open my $fh, '<', $leaseFile or die $!; while (<$fh>) { my ($ip) = /\s+(\S+)\s+/ or next; my $client = /client-hostname\s+(".+")/ ? $1 : ''; print "$ip,$client\n"; } close $fh;` [download]	[reply] [d/l]