#include <sys/types.h>
#include <unistd.h>
#include <stdio.h>

int
main(int ac, char *av[])
{
    pid_t child = fork();
    if (child != 0) {
        wait(NULL);
        printf ("I'm the parent %d, my child is  %d\n", 
            getpid(), child);
    } else {
        printf ("I'm the child  %d, my parent is %d\n", 
            getpid(), getppid());

        execl("/bin/echo", "echo", "Hello, World", NULL);
    }
}