#! /usr/bin/perl
use warnings;
use strict;
use Socket;
use Sys::Hostname;

my $iaddr = gethostbyname(hostname());
my $proto = getprotobyname('udp');
my $paddr = sockaddr_in(0, $iaddr); # 0 means let kernel pick

socket(SOCKET, PF_INET, SOCK_DGRAM, $proto)   || die "socket: $!";
bind(SOCKET, $paddr)                          || die "bind: $!";

my ($hispaddr, $hisiaddr, $hisport);
$hisport = 9999;
$hisiaddr = inet_aton($ARGV[0])    || die "unknown host " . $ARGV[0];
$hispaddr = sockaddr_in($hisport, $hisiaddr);

defined(send(SOCKET, "hi", 0, $hispaddr))    || die "send: $!";