diff --git a/coreutils/chroot.c b/coreutils/chroot.c
index 7f3268e..791eb97 100644
--- a/coreutils/chroot.c
+++ b/coreutils/chroot.c
@@ -4,20 +4,22 @@
 #include <string.h>
 #include <errno.h>
 
-int main(const int argc, const char **argv) {
-	if (argc < 3) {
+int main(const int argc, char **argv) {
+	if (argc < 3 || !strcmp(argv[argc - 1], "-h")) {
 		printf("chroot [dir] [\"command arg\"]\n");
 		return 0;
 	}
 
-	if (chroot(argv[1]) == -1) {
+	if (chroot(argv[1]) < 0) {
 		fprintf(stderr, "chroot: %s\n", strerror(errno));
 		return 1;
 	}
 
 	chdir("/");
-	for (int i = 1; i < argc; i++)
-		system(argv[i]);
+	if (execvp(argv[2], argv) < 0) {
+		fprintf(stderr, "chroot: %s\n", strerror(errno));
+		return 1;
+	}
 
 	return 0;
 }
diff --git a/coreutils/mv.c b/coreutils/mv.c
index bf44f57..cd3f4c2 100644
--- a/coreutils/mv.c
+++ b/coreutils/mv.c
@@ -31,9 +31,9 @@ int move(const char *src, const char *dst) {
 }
 
 int main(const int argc, const char **argv) {
-	if (argc == 2) {
-		printf("mv: missing operand\n");
-		return 1;
+	if (argc <= 2 || !strcmp(argv[argc - 1], "-h")) {
+		printf("mv [Src1 src2...] [Dst]\n");
+		return 0;
 	}
 
 	for (int i = 1; i < argc - 1; i++) {
diff --git a/coreutils/rm.c b/coreutils/rm.c
index 35da044..44ac6f6 100644
--- a/coreutils/rm.c
+++ b/coreutils/rm.c
@@ -59,9 +59,9 @@ int rmtree(const char *path) {
 }
 
 int main(const int argc, char **argv) {
-	if (argc == 1) {
-		printf("rm: missing operand\n");
-		return 1;
+	if (argc == 1 || !strcmp(argv[argc - 1], "-h")) {
+		printf("rm [src1 src2...]\n");
+		return 0;
 	}
 
 	for (int i = 1; i < argc; i++) {
diff --git a/coreutils/sleep.c b/coreutils/sleep.c
index 3fe2b30..96ad38f 100644
--- a/coreutils/sleep.c
+++ b/coreutils/sleep.c
@@ -13,8 +13,8 @@ double convert(const char *num) {
 }
 
 int main(const int argc, const char **argv) {
-	if (argc == 1) {
-		printf("sleep [num[m - minute / h - hour / d - days].. ] / [inf (infinity)]\n");
+	if (argc == 1 || !strcmp(argv[argc - 1], "-h")) {
+		printf("sleep [num[m - minute / h - hour / d - days]] / [inf (infinity)]\n");
 		return 0;
 	}