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

int main()
{
   pid_t pid;
   pid = fork();      /* fork another process */

   if (pid < 0)       /* Forking error! */
      {   exit(-1);   }
   else if (0 == pid) /* Child process */ 
      {
	// The exec() call replaces the process image of the child
	//  with a new process image; instead of running myFirstFork,
	//  the child will contain the 'ls' program.
	execlp("/bin/ls", "ls", NULL);
	// Notice that if the exec() function works, nothing else below
	//  this line should be executed by the child process.  The
	//  exec() call replaces the program that the child process
	//  is running with the 'ls' program, and the child process
	//  never comes back to the old code.
	fprintf(stderr, "Why am I still alive?  Exec() must have failed!\n");
      }
   else               /* pid > 0: Parent process */
      {   
          printf("Child process is %d\n", pid);
          wait(NULL);
          exit(0);
      }
}