Examples :
shell
|
a
/ \
b e
/ \ \
c d f
$ ./a.out ddduduudduuu abcdef
I'm c, my pid=9693, and my ppid=9692
I'm d, my pid=9695, and my ppid=9692
I'm f, my pid=9696, and my ppid=9694
I'm e, my pid=9694, and my ppid=9691
I'm b, my pid=9692, and my ppid=9691
I'm a, my pid=9691, and my ppid=9572
child 9693 signaled with signal 1 $ kill -1 9693 # node c
child 9696 signaled with signal 2 $ kill -2 9696 # node f
child 9694 exited with value 2 # node e exited
child 9695 signaled with signal 3 $ kill -3 9695 # node d
child 9692 exited with value 3 # node b exited
$ echo $? # node a exited
6
$