After a program executes the following series of fork() calls, how many new processes will result (assuming that none of the calls fails)?

Write a program to demonstrate that after a vfork(), the child process can close a file descriptor (e.g., descriptor 0) without affecting the corresponding file descriptor in the parent.

Assuming that we can modify the program source code, how could we get a core dump of a process at a given moment in time, while letting the process continue execution?

fork (); fork(); fork ();