$pid = open(KID_TO_READ, "-|") or die "fork: $!";
if ($pid) {   # parent
    while (<KID_TO_READ>) {
      # do something interesting
    }
    close(KID_TO_READ) or warn "kid exited $?";
} else {      # child                
    exec($program, @args) or die "can't exec program: $!";
    # NOTREACHED
}