update do_pipe

yeeshell.c

@@ -250,6 +250,7 @@ int do_pipe(char **pipe_arg_1, char **pipe_arg_2)
 			exit(0);
 		}
 	}
+	waitpid(prog_1, NULL, 0);
 
 	if ((prog_2 = fork()) == 0) /* Child process 2 */
 	{
@@ -264,12 +265,11 @@ int do_pipe(char **pipe_arg_1, char **pipe_arg_2)
 			exit(0);
 		}
 	}
+	waitpid(prog_2, NULL, 0);
 
 	close(fds[0]);
 	close(fds[1]);
 
-	waitpid(prog_1, NULL, 0);
-	waitpid(prog_2, NULL, 0);
 	return 1;
 }