Rewrite the program in Step 1., so that the child process runs the ls command, and that the parent parent process waits until the child process terminates before it exits. Demonstrate your code to the TA. You may use the following code snippet.

else if(pid == 0)

{

execlp("/bin/ls", "ls", NULL);

}

else

{

wait(NULL);

printf("Child Complete");

exit(0);

}

Step 1:

#include /* printf, stderr */

#include /* pid_t */

#include /* fork */

#include /* atoi */

#include /* errno */

/* main function with command-line arguments to pass */

int main(int argc, char *argv[]) {

pid_t pid;

int i, n = atoi(argv[1]); // n microseconds to input from keyboard for delay

printf(" Before forking. ");

pid = fork();

if (pid == -1) {

fprintf(stderr, "can't fork, error %d ", errno);

}

if (pid){

// Parent process

for (i=0;i<100;i++) {

printf("\t \t \t Parent Process %d ",i);

usleep(n);

}

}

else{

// Child process

for (i=0;i<100;i++) {

printf("Child process %d ",i);

usleep(n);

}

}

return 0;

}