diff --git a/a.out b/a.out
deleted file mode 100755
index 59770eb..0000000
Binary files a/a.out and /dev/null differ
diff --git a/builds/microshell.o b/builds/microshell.o
index 9e5e888..96350c0 100644
Binary files a/builds/microshell.o and b/builds/microshell.o differ
diff --git a/microshell b/microshell
index 191582a..4d6ea3d 100755
Binary files a/microshell and b/microshell differ
diff --git a/microshell.c b/microshell.c
index 54d7b34..74c4ad3 100644
--- a/microshell.c
+++ b/microshell.c
@@ -1,4 +1,4 @@
-#include <unistd.h>		// write, fork, execve, pipe
+#include <unistd.h>		// write, fork, execve, pipe, chdir
 #include <stdio.h>		// printf
 #include <string.h>		// strcmp
 #include <sys/types.h>	// pid_t
@@ -8,36 +8,37 @@
 #define STDOUT	1
 #define STDERR	2
 
-void	print_cmd(char **av)
-{
-	int i;
-	int size;
+typedef enum {FALSE, TRUE} BOOL;
 
-	i = 0;
-	while (av[i])
-	{
-		size = 0;
-		while (av[i][size] != '\0')
-			size++;
-		write(1, av[i], size);
-		write(1, " ", 1);
-		i++;
-	}
-	write(1, "\n", 1);
+void	builtin_cd(char *av)
+{
+	printf("here\n");
+	if (av)
+		chdir(av);
 }
 
-//void	exec_cmd(char **av, int end, char **en)
-void	exec_cmd(char **av, char **en)
+void	exec_cmd(char **av, char **en, int fdin, int fdout)
 {
 	pid_t	pid = fork();
 
-//	av[end] = NULL;
 	if (pid == 0)	// child process
 	{
+		if (fdin != STDIN_FILENO)
+		{
+			dup2(fdin, STDIN_FILENO);
+			close(fdin);
+		}
+		if (fdout != STDOUT_FILENO)
+		{
+			dup2(fdout, STDOUT_FILENO);
+			close(fdout);
+		}
 		execve(av[0], av, en);
 	}
 	else			// parent process
 	{
+		if (fdout != STDOUT_FILENO)
+			close(fdout);
 		waitpid(pid, NULL, 0);
 	}
 }
@@ -46,22 +47,38 @@ int	main(int ac, char **av, char **en)
 {
 	int i;
 	int start;
+	int	fds[2];
+	int	old_fdin;
 
 	if (ac <= 1)
 		return (0);
 	i = 1;
+	old_fdin = STDIN_FILENO;
+	fds[STDIN] = STDIN_FILENO;
+	fds[STDOUT] = STDOUT_FILENO;
 	while (i < ac)
 	{
 		start = i;
 		while (i < ac && strcmp(av[i], "|") && strcmp(av[i], ";"))
 			i++;
+		if (av[i] && !strcmp(av[i], "|"))
+			pipe(fds);
 		av[i] = NULL;
-//		print_cmd(&av[start]);
-		exec_cmd(&av[start], en);
+		if (strcmp(av[start], "cd") == 0)
+			builtin_cd(av[start + 1]);
+		else
+			exec_cmd(av + start, en, old_fdin, fds[STDOUT]);
+		if (old_fdin != STDIN_FILENO)
+			close(old_fdin);
+		old_fdin = fds[STDIN];
+		fds[STDOUT] = STDOUT_FILENO;
 		if (i < ac)
 			i++;
 	}
 	return (0);
 }
 
-// https://www.rozmichelle.com/pipes-forks-dups/
+// pipes fork and dups : https://www.rozmichelle.com/pipes-forks-dups/
+// subject and example : https://github.com/Glagan/42-exam-rank-04
+// lsof -c microshell  : https://www.thegeekstuff.com/2012/08/lsof-command-examples/
+