diff --git a/coreutils/chmod.c b/coreutils/chmod.c
index bbd163e..5ec51ac 100644
--- a/coreutils/chmod.c
+++ b/coreutils/chmod.c
@@ -99,7 +99,7 @@ int main(int argc, char **argv) {
 				break;
 
 			default:
-				printf("chmod [ugoa]{+|-|=}[rwxXst] / [sstrwxrwxrwx] [file1 file2...]\n\t[-H if a command line argument is a symbolic link]\n\t[-R recursive] [-s silent]\n");
+				printf("chmod [ugoa]{+|-}[rwxXst] / [0 - 777] [file1 file2...]\n\t[-H if a command line argument is a symbolic link]\n\t[-R recursive] [-s silent]\n");
 				return 0;
 		}
 	}
diff --git a/coreutils/chown.c b/coreutils/chown.c
index 92a0c5b..e3959b2 100644
--- a/coreutils/chown.c
+++ b/coreutils/chown.c
@@ -104,48 +104,46 @@ void get_owner(const char *arg) {
 	}
 }
 
-int main(const int argc, char **argv) {
+int main(int argc, char **argv) {
 	get_stat = mu_get_lstat;
 	chown_func = lchown;
 
-	int i;
-	for (i = 1; i < argc; i++) {
-		if (argv[i][0] != '-')
-			break;
+	int opt;
+	while ((opt = getopt(argc, argv, "RfH") != -1)) {
+		switch (opt) {
+			case 'R':
+				r_flag = 1;
+				break;
 
-		else if (!strcmp(argv[i], "-r"))
-			r_flag = 1;
+			case 'f':
+				s_flag = 1;
+				break;
 
-		else if (!strcmp(argv[i], "-s"))
-			s_flag = 1;
+			case 'H':
+				chown_func = chown;
+				get_stat = mu_get_stat;
+				break;
 
-		else if (!strcmp(argv[i], "-H")) {
-			chown_func = chown;
-			get_stat = mu_get_stat;
-		}
-
-		else if (!strcmp(argv[i], "--help")) {
-			printf("chown [group] [file1 file2...]\n\t[-H if a command line argument is a symbolic link]\n\t[-r recursive]\n");
-			return 0;
+			default:
+				printf("chown [group] [file1 file2...]\n\t[-H if a command line argument is a symbolic link]\n\t[-r recursive]\n");
+				return 0;
 		}
 	}
 
-	if (argc - i == 0) {
+	if (argv[optind] == NULL) {
 		fprintf(stderr, "chown: missing operand\n");
 		return 1;
 	}
 
 	gid = -1;
 	uid = -1;
-	get_owner(argv[i++]);
+	get_owner(argv[optind]);
 
-	if (argc - i == 0) {
-		fprintf(stderr, "chown: missing operand\n");
-		return 1;
-	}
+	argv += optind;
+	argc -= optind;
 
 	int ret = 0;
-	for (; i < argc; i++)
+	for (int i = 1; i < argc; i++)
 		if (cntree(argv[i]))
 			ret = 1;
 
diff --git a/coreutils/chroot.c b/coreutils/chroot.c
index 99c7556..99a5910 100644
--- a/coreutils/chroot.c
+++ b/coreutils/chroot.c
@@ -6,7 +6,7 @@
 
 int main(const int argc, char **argv) {
 	if (argc < 3 || !strcmp(argv[argc - 1], "--help")) {
-		printf("chroot [dir] [command arg arg2...]\n");
+		printf("chroot [dir] [command] [arg arg2...]\n");
 		return 0;
 	}
 
diff --git a/coreutils/cp.c b/coreutils/cp.c
index 44e0fd1..908ef01 100644
--- a/coreutils/cp.c
+++ b/coreutils/cp.c
@@ -10,6 +10,8 @@
 #include "make_path.h"
 #include "get_stat.h"
 
+unsigned int s_flag;
+
 int write_buffer(int mode, int ifd, int ofd, const char *dst) {
 	off_t len = lseek(ifd, 0, SEEK_END);
 	if (len <= 0) {
@@ -81,7 +83,8 @@ int copy(int mode, const char *src, const char *dst) {
 	}
 
 	if (write_buffer(mode, ifd, ofd, new_path))
-		fprintf(stderr, "cp: (%s %s) %s\n", src, dst, strerror(errno));
+		if (!s_flag)
+			fprintf(stderr, "cp: (%s %s) %s\n", src, dst, strerror(errno));
 
 
 	close(ofd);
@@ -106,7 +109,9 @@ int cptree(const char *src, const char *dst) {
 
 	if (!S_ISDIR(stat_path.st_mode)) {
 		if (copy(stat_path.st_mode, src, dst)) {
-			fprintf(stderr, "cp: (%s %s): copy() failed (%s)\n", src, dst, strerror(errno));
+			if (!s_flag)
+				fprintf(stderr, "cp: (%s %s): copy() failed (%s)\n", src, dst, strerror(errno));
+
 			return 1;
 		}
 
@@ -114,7 +119,8 @@ int cptree(const char *src, const char *dst) {
 	}
 
 	else if (mkdir(dst, 0777) < 0)
-		fprintf(stderr, "cp: %s\n", strerror(errno));
+		if (!s_flag)
+			fprintf(stderr, "cp: %s\n", strerror(errno));
 
 	DIR *dir = opendir(src);
 	if (dir == NULL) {
@@ -150,25 +156,38 @@ int cptree(const char *src, const char *dst) {
 	return ret;
 }
 
-int main(const int argc, char **argv) {
+int main(int argc, char **argv) {
+	int opt;
+	while ((opt = getopt(argc, argv, "frR")) != -1) {
+		switch (opt) {
+			case 'f':
+				s_flag = 1;
+				break;
 
-	int i;
-	for (i = 1; i < argc; i++) {
-		if (argv[i][0] != '-')
-			break;
+			case 'r':
+			case 'R':
+				break;
 
-		else if (!strcmp(argv[i], "--help")) {
-			printf("cp [Src] [Dst]\n");
-			return 0;
+			default:
+				printf("chmod [src1 src2...] [dst]\n\t[-f silent]\n");
+				return 0;
 		}
 	}
 
+	if (argv[optind] == NULL) {
+		fprintf(stderr, "cp: missing operand\n");
+		return 1;
+	}
+
+	argv += optind;
+	argc -= optind;
+
 	int ret = 0;
-	if (argc - i == 2)
-		ret = cptree(argv[i], argv[argc - 1]);
+	if (argc == 2)
+		ret = cptree(argv[0], argv[argc - 1]);
 
 	else {
-		for (; i < argc - 1; i++) {
+		for (int i = 1; i < argc - 1; i++) {
 			char *new_path = mu_make_path("cp", argv[argc - 1], basename(argv[i]));
 			if (new_path == NULL)
 				return 1;
diff --git a/coreutils/du.c b/coreutils/du.c
index 5714801..e59a04e 100644
--- a/coreutils/du.c
+++ b/coreutils/du.c
@@ -48,7 +48,7 @@ double du(const char *path, int recurs_flag) {
 
 	struct stat sb;
 	if (mu_get_lstat("du", path, &sb))
-		return 1;
+		return 0;
 
 	if (S_ISDIR(sb.st_mode)) {
 		DIR *dp = opendir(path);
@@ -64,7 +64,7 @@ double du(const char *path, int recurs_flag) {
 
 			char *new_path = mu_make_path("du", path, ep->d_name);
 			if (new_path == NULL)
-				return 1;
+				return 0;
 
 			sum += du(new_path, 1);
 
@@ -92,39 +92,46 @@ double du(const char *path, int recurs_flag) {
 	return sum;
 }
 
-int main(const int argc, const char **argv) {
+int main(int argc, char **argv) {
 
-	int i;
-	for (i = 1; i < argc; i++) {
-		if (argv[i][0] != '-')
-			break;
+	int opt;
+	while ((opt = getopt(argc, argv, "hsbm")) != -1) {
+		switch (opt) {
+			case 'h':
+				h_flag = 1;
+				break;
 
-		else if (!strcmp(argv[i], "-h"))
-			h_flag = 1;
+			case 's':
+				s_flag = 1;
+				break;
 
-		else if (!strcmp(argv[i], "-s"))
-			s_flag = 1;
+			case 'b':
+				b_flag = 1;
+				break;
 
-		else if (!strcmp(argv[i], "-b"))
-			b_flag = 1;
+			case 'm':
+				b_flag = 1;
+				m_flag = 1;
+				break;
 
-		else if (!strcmp(argv[i], "-m")) {
-			b_flag = 1;
-			m_flag = 1;
-		}
 
-		else if (!strcmp(argv[i], "--help")) {
-			printf("du [-h Sizes in human readable format (e.g., 1K 243M 2G)] [-s Display only a total for each argument] [-b Apparent size] [-m Size in megabyte] [file file2...]\n");
-			return 0;
+			default:
+				printf("du [file1 file2...]\n\t[-h Sizes in human readable format (e.g., 1K 243M 2G)]\n\t[-s Display only a total for each argument]\n\t[-b Apparent size] [-m Size in megabyte]\n");
+				return 0;
 		}
 	}
 
-	if (argc - i == 0)
+	if (argv[optind] == NULL)
 		du(".", 0);
 
-	else
-		for (; i < argc; i++)
+	else {
+		argv += optind;
+		argc -= optind;
+		for (int i = 0; i < argc; i++)
 			du(argv[i], 0);
 
+	}
+
 	return 0;
 }
+
diff --git a/coreutils/rm.c b/coreutils/rm.c
index d29590e..10c8970 100644
--- a/coreutils/rm.c
+++ b/coreutils/rm.c
@@ -55,33 +55,43 @@ int rmtree(const char *path) {
 	return ret;
 }
 
-int main(const int argc, 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, "frR")) != -1) {
+		switch (opt) {
+			case 'f':
+				f_flag = 1;
+				break;
 
-		else if (!strcmp(argv[i], "-f"))
-			f_flag = 1;
+			case 'r':
+			case 'R':
+				break;
 
-		else if (!strcmp(argv[i], "--help")) {
-			printf("rm [-f force] file1 file2...\n");
-			return 0;
+			default:
+				printf("rm [file1 file2...]\n\t[-f force]\n");
+				return 0;
 		}
 	}
 
-	int status = 0;
-	for (; i < argc; i++) {
+	if (argv[optind] == NULL) {
+		fprintf(stderr, "rm: missing operand\n");
+		return 1;
+	}
+
+	argv += optind;
+	argc -= optind;
+
+	int ret = 0;
+	for (int i = 0; i < argc; i++) {
 		if (!strcmp(argv[i], ".") || !strcmp(argv[i], "..")){
 			printf("rm: refusing to remove '.' or '..' directory\n");
 			break;
 		}
 
-		int status = rmtree(argv[i]);
-		if (status != 0)
-			status = 1;
+		if (rmtree(argv[i]))
+			ret = 1;
 	}
 
-	return status;
+	return ret;
 }