die "can't fork: $!" unless defined($kidpid = fork());

if ($kidpid) {                      
   # parent sleeps 60 seconds and then kills child
   sleep 60;
   kill("TERM" => $kidpid);        # send SIGTERM to child
} else {                              
   # child does wget
   ...
}
print "$kidpid exitting\n";
exit;