open(INPUTF, $ARGV[0]) || die("can't open filein:".$ARGV[0]);
$retval = open(FROMCHILD, "-|");
if ($retval) {
    # this is the parent process

    print "father print: my son is ".$retval."\n";
     $line = "";
     close(STDIN);
    while(<FROMCHILD>)
    {
        $line = $_;
        print "father print:".$line;
        if($line =~ m/this\sis\sa\stest/g)
        {
            while(kill 0 => $retval)
            {
                print "father print: i should terminate my son:".$retval."\n";
                kill (9, $retval);
            }
        }
    }
} else {
    # this is the child process

    while(<INPUTF>)
    {
        print $_;
        sleep(1);
    }
    exit;
}