#!/usr/bin/perl -T
use strict;
use warnings;
$|=1;

# ipaddr2int.pl - convert IPv4 addresses from stdin to integers on stdout
# $Id: ipaddr2int.pl,v 1.1 2009/10/01 13:46:20 jtk Exp $

while ( defined(my $line=<>) ) {
    chomp $line;
    next if $line !~ m{ \A \d{1,3} (?: [.] \d{1,3}){3} \Z }xms;
    my @bytes = split /\./, $line;
    my $int = unpack( "N", pack("C4", @bytes) );
    print "$int\n";
}