ip2name.pl

#!/usr/bin/perl

use strict;

my $AF_INET     = 2;

print ip2name($ARGV[0]);
print "\n";

sub ip2name{
	my($ip) = shift;

	my $addr = pack("C4", split(/\./, $ip));
	my $name = gethostbyaddr($addr, $AF_INET) ;
	
	$name ? $name : $ip;

}