diff --git a/builder/builder.c b/builder/builder.c
index 34010c7..f1a2080 100644
--- a/builder/builder.c
+++ b/builder/builder.c
@@ -35,18 +35,10 @@ void Compile(const char *src, const char *output_dir) {
 	char *path = MakePath(src, output_dir);
 	printf("[CC] Building %s -> %s\n", src, path);
 
-	size_t len = strlen(CC) + strlen(CFLAGS) + strlen(src) + strlen(path) + 7;
-	char *arg = malloc(len + 1);
-	if (arg == NULL) {
-		free(path);
-		fprintf(stderr, "builder: malloc failed");
-		exit(1);
+	if (fork()) {
+		execlp(CC, CC, CFLAGS, src, "-o", path, NULL);
 	}
-
-	snprintf(arg, len, "%s %s %s -o %s", CC, CFLAGS, src, path);
-	system(arg);
-
-	free(arg);
+	
 	free(path);
 }
 
diff --git a/builder/config.h b/builder/config.h
index 0274fa1..e47e89d 100644
--- a/builder/config.h
+++ b/builder/config.h
@@ -14,6 +14,6 @@ const char *libs[] = {
 	"readline"
 };
 
-#define CFLAGS "-Wall -Wextra -pedantic -Os -s -I ../libmu"
+#define CFLAGS "-Wall", "-Wextra", "-pedantic", "-Os", "-s", "-I", "../libmu"
 #define CC "cc"
 #endif
diff --git a/coreutils/cat.c b/coreutils/cat.c
index 8ecda05..d3e3c97 100644
--- a/coreutils/cat.c
+++ b/coreutils/cat.c
@@ -14,13 +14,16 @@ void cat(const int fd) {
 }
 
 int main(const int argc, const char **argv) {
-	if (argc == 1 || argv[1][0] == '-')
+	if (argc == 1)
 		cat(STDIN_FILENO);
 
 	else {
 		for (int i = 1; i < argc; i++) {
 			if (argv[i][0] == '-')
-				break;
+				if (argv[i][1])
+					break;
+				else
+					cat(STDIN_FILENO);
 
 			int fd = open(argv[i], O_RDONLY);
 			if (fd < 0) {
diff --git a/coreutils/echo.c b/coreutils/echo.c
index e4fe93a..9146b2b 100644
--- a/coreutils/echo.c
+++ b/coreutils/echo.c
@@ -8,7 +8,8 @@ int main(const int argc, const char **argv) {
 				putchar(' ');
 		}
 	}
-
+	// https://pubs.opengroup.org/onlinepubs/009604599/utilities/echo.html
+	// This version does not support -n option and escape-sequences
 	putchar('\n');
 	return 0;
 }