two = fork();

    switch (two) {
        case -1 :
            perror("Cannot fork.");
            exit(1);
        case 0 :
            close(p0[WRITE]);
            dup2(p0[READ], STDIN_FILENO);
            close(p0[READ]);

            dup2(s0, STDOUT_FILENO);
            dup2(s0, STDERR_FILENO);  /* duplicate socket on stderr too */

            execlp("/bin/sh", "sh", "-c", "grep rwxr-xr-x", NULL);
            perror("execl");
            exit(1);
    }

    three = fork();

    switch (three) {
        case -1 :
            perror("Cannot fork.");
            exit(1);
        case 0 :
            dup2(s0, STDIN_FILENO);
            dup2(s0, STDOUT_FILENO);
            dup2(s0, STDERR_FILENO);  /* duplicate socket on stderr too */

            execlp("/bin/sh", "sh", "-c", "cat", NULL);
            perror("execl");
            exit(1);
    }