find_line_with_ip.pl

#!/usr/bin/perl
use Net::CIDR::Lite;
use Getopt::Std;

my %options=();

my $cidr = Net::CIDR::Lite->new;

getopts("n:f:",\%options);
if( defined $options{f} ){
        open FD, "<$options{f}" or die("Cannot open $options{f}: $!\n" );
        while( <FD> ){
                chomp;
                $cidr->add( $_ );
        }
} else {
        die("You must specify a cidr address with -n\n" ) unless defined $options{n};
        $cidr->add( $options{n} );
}

while( <> ){
        my $ip = $1 if /\b(\d+\.\d+\.\d+\.\d+)\b/;
        print if $cidr->find( $ip );
}