diff --git a/TODO b/TODO
index ed62857..88aa615 100644
--- a/TODO
+++ b/TODO
@@ -2,6 +2,7 @@ PlainOs
 With "micro-" prefix
 
 *Todo:
+ls
 tail
 uniq
 head
diff --git a/build b/build
new file mode 100755
index 0000000..8808f26
Binary files /dev/null and b/build differ
diff --git a/builder/builder.c b/builder/builder.c
index 035e82d..7f18ca5 100644
--- a/builder/builder.c
+++ b/builder/builder.c
@@ -4,6 +4,9 @@
 #include <string.h>
 #include <stdlib.h>
 #include <unistd.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <signal.h>
 #include "make_path.h"
 #include "config.h"
 
@@ -35,8 +38,19 @@ void Compile(const char *src, const char *output_dir) {
 	char *path = MakePath(src, output_dir);
 	printf("[CC] Building %s -> %s\n", src, path);
 
-	if (fork())
+	pid_t pid;
+	if ((pid = fork()) == 0) {
 		execlp(CC, CC, CFLAGS, src, "-o", path, NULL);
+		kill(getpid(), 9);
+
+		/* If compiler return 1 */
+		exit(1);
+	}
+
+	int status = 0;
+	waitpid(pid, &status, 0);
+	if (status)
+		exit(1);
 
 	free(path);
 }
diff --git a/coreutils/ls.c b/coreutils/ls.c
index 4c6111c..2f47e29 100644
--- a/coreutils/ls.c
+++ b/coreutils/ls.c
@@ -14,6 +14,7 @@
 
 unsigned int a_flag;
 unsigned int l_flag;
+unsigned int p_flag;
 
 void PrintPerm(struct stat sb) {
 	if (S_ISDIR(sb.st_mode))
@@ -131,34 +132,29 @@ int list(const char *path, int label) {
 
 
 
-int main(const int argc, const char **argv) {
-	int i;
-	for (i = 1; i < argc; i++) {
-		if (argv[i][0] != '-')
-			break;
+int main(int argc, char **argv) {
+	int opt;
+	while ((opt = getopt(argc, argv, "al")) != -1) {
+		switch (opt) {
+			case 'a':
+				a_flag = 1;
+				break;
 
-		else if (!strcmp(argv[i], "-a"))
-			a_flag = 1;
+			case 'l':
+				l_flag = 1;
+				break;
 
-		else if (!strcmp(argv[i], "-l"))
-			l_flag = 1;
-
-		else if (!strcmp(argv[i], "--help")) {
-			printf("ls [-a show hidden files] [-l use a long listing format] [Path]\n");
-			return 0;
+			default:
+				printf("ls [path]\n\t[-a Show hidden files] [-l Use a long listing format]\n");
+				return 0;
 		}
 	}
 
-	if (i == argc)
-		return list(".", 0);
+	argv += optind;
+	argc -= optind;
 
-	if (i == argc - 1)
-		return list(argv[i], 0);
-
-	else
-		for (; i < argc; i++)
-			if (list(argv[i], 1))
-				return 1;
+	if (argc == 0)
+		list(".", 0);
 
 	return 0;
 }