#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
//ipc-shell-1.c
main()
{
	int pfd[2];
	pipe(pfd);
	switch(fork()) {
		case -1:printf("error in fork");
			exit(1);

		case 0:	if (close(1) == -1) {
				printf("error in close(1)");
				exit(1);
			}
			dup(pfd[1]);
			close(pfd[0]); close(pfd[1]);
			execlp("who", "who", NULL);
			printf("error in execl1");
			exit(1);
	}

	switch(fork()) {
		case -1:printf("error in fork");
			exit(1);

		case 0:	if(close(0) == -1){
	 			printf("error in close(0)");
				exit(1);
			}
			dup(pfd[0]);
			close(pfd[0]); close(pfd[1]);
			execlp("wc", "wc", NULL);
			printf("error in execl2");
			exit(1);
	}
	close(pfd[0]); close(pfd[1]);
	wait(NULL) ;
}