#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
main()
{
	int pfd[2];
	if(pipe(pfd) == -1) err_sys("pipe");
	switch(fork()) {
		case -1: err_sys("fork");
		case 0:	if (close(1) == -1) err_sys("close");
			if (dup(pfd[1]) != 1) err_sys("dup");
			if (close(pfd[0]) == -1 || close(pfd[1]) == -1) err_sys("close2");
			execlp("ls", "ls", NULL);
			err_sys("execl1");
	}

	switch(fork()) {
		case -1:err_sys("fork");
		case 0:	if(close(0) == -1) err_sys("close3");
			if (dup(pfd[0]) != 0) err_sys("dup2");
			if (close(pfd[0]) == -1 || close(pfd[1]) == -1) err_sys("close4");
			execlp("wc", "wc", NULL);
			err_sys("execl2");
	}
	if (close(pfd[0]) == -1 || close(pfd[1]) == -1) err_sys("close5");
	wait(NULL) ;
}