diff --git a/README.md b/README.md
index 71cc180..de64498 100644
--- a/README.md
+++ b/README.md
@@ -1,7 +1,7 @@
 # micro-utils
 [Compile]
-	cc builder.c -Ilibmu -obuilder
-	./builder
+	cc builder/builder.c -Ilibmu -obuild
+	./build
 
 [or]
 	sh build.sh
diff --git a/TODO b/TODO
index 232d09d..08aaddf 100644
--- a/TODO
+++ b/TODO
@@ -2,7 +2,6 @@ PlainOs
 With "micro-" prefix
 
 *Todo:
-cmp
 tail
 uniq
 head
diff --git a/build.sh b/build.sh
old mode 100755
new mode 100644
index 0e5300b..e8160f5
--- a/build.sh
+++ b/build.sh
@@ -1,3 +1,3 @@
 #!/bin/sh
-cc builder.c -Wall -Wextra -Os -s -pedantic -Ilibmu -obuilder
-./builder && rm builder
+cc builder/builder.c -Wall -Wextra -Os -s -pedantic -Ilibmu -obuild
+./build && rm build
diff --git a/builder.c b/builder/builder.c
similarity index 73%
rename from builder.c
rename to builder/builder.c
index 4c4f12a..d4da446 100644
--- a/builder.c
+++ b/builder/builder.c
@@ -13,7 +13,7 @@ void remove_suffix(char *base, const char *suffix) {
 		*ptr = '\0';
 }
 
-char *MakePath(char *src) {
+char *MakePath(const char *src, const char *output_dir) {
 	char *dup = strdup(src);
 	if (dup == NULL) {
 		fprintf(stderr, "builder: strdup failed");
@@ -21,7 +21,7 @@ char *MakePath(char *src) {
 	}
 
 	remove_suffix(dup, ".c");
-	char *new_path = mu_make_path("builder", "../bin", dup);
+	char *new_path = mu_make_path("builder", output_dir, dup);
 	if (new_path == NULL) {
 		free(dup);
 		exit(1);
@@ -31,8 +31,8 @@ char *MakePath(char *src) {
 	return new_path;
 }
 
-void Compile(char *src) {
-	char *path = MakePath(src);
+void Compile(const char *src, const char *output_dir) {
+	char *path = MakePath(src, output_dir);
 
 	size_t len = strlen(CC) + strlen(CFLAGS) + strlen(src) + strlen(path) + 7;
 	char *arg = malloc(len + 1);
@@ -49,7 +49,7 @@ void Compile(char *src) {
 	free(path);
 }
 
-void ListAndCompile(const char *dir) {
+void ListAndCompile(const char *dir, const char *output_dir) {
 	chdir(dir);
 	DIR *dp = opendir(".");
 	if (dp == NULL) {
@@ -63,7 +63,7 @@ void ListAndCompile(const char *dir) {
 			continue;
 
 		printf("[INFO] Building %s\n", ep->d_name);
-		Compile(ep->d_name);
+		Compile(ep->d_name, output_dir);
 
 	}
 
@@ -72,8 +72,11 @@ void ListAndCompile(const char *dir) {
 }
 
 int main(void) {
+	/* for (size_t i = 0; i < sizeof(libs) / sizeof(char *); i++)
+		ListAndCompile(objects[i], "../obj"); */
+
 	for (size_t i = 0; i < sizeof(objects) / sizeof(char *); i++)
-		ListAndCompile(objects[i]);
+		ListAndCompile(objects[i], "../bin");
 
 	return 0;
 }
diff --git a/config.h b/builder/config.h
similarity index 84%
rename from config.h
rename to builder/config.h
index 1e7913a..05eeb48 100644
--- a/config.h
+++ b/builder/config.h
@@ -9,6 +9,10 @@ const char *objects[] = {
 	"shell"
 };
 
+const char *libs[] = {
+	"readline"
+};
+
 #define CFLAGS "-Wall -Wextra -pedantic -Os -s -I ../libmu"
 #define CC "cc"
 #endif
diff --git a/coreutils/cmp.c b/coreutils/cmp.c
new file mode 100644
index 0000000..c1af7d9
--- /dev/null
+++ b/coreutils/cmp.c
@@ -0,0 +1,114 @@
+#include <stdio.h>
+#include <errno.h>
+#include <string.h>
+#include <stdlib.h>
+unsigned int s_flag;
+
+int compare(FILE *fp1, FILE *fp2) {
+	if (fp1 == fp2)
+		return 0;
+
+	int ch1;
+	int ch2;
+
+	size_t byte = 0;
+	do {
+		ch1 = getc(fp1);
+		ch2 = getc(fp2);
+
+		if (ch1 != ch2) {
+			if (!s_flag)
+				printf("files differ at byte %lu\n", byte);
+
+			return 1;
+		}
+
+		byte++;
+	} while(ch1 != EOF);
+
+	return 0;
+}
+
+long parse_int(const char *str) {
+	char *ptr;
+	long val = strtol(str, &ptr, 0);
+	if (*ptr || val < 0) {
+		fprintf(stderr, "cmp: invalid offset: %s\n", str);
+		exit(1);
+	}
+
+	return val;
+}
+
+FILE *file_open(const char *path) {
+	if (!strcmp(path, "-"))
+		return stdin;
+
+	FILE *fp = fopen(path, "r");
+	if (fp == NULL) {
+		fprintf(stderr, "cmp: %s\n", strerror(errno));
+		exit(1);
+	}
+
+	return fp;
+}
+
+int main(const int argc, const char **argv) {
+	int i;
+	for (i = 1; i < argc; i++) {
+		if (argv[i][0] != '-')
+			break;
+
+		else if (!strcmp(argv[i], "-s"))
+			s_flag = 1;
+
+		else if (!strcmp(argv[i], "--help")) {
+			printf("cmp [-s silent] FILE1 FILE2 [SKIP1] [SKIP2]\n");
+			return 0;
+		}
+	}
+
+
+	long skip1 = 0;
+	long skip2 = 0;
+	FILE *fp1 = NULL;
+	FILE *fp2 = stdin;
+
+	switch (argc - i) {
+		case 4:
+			skip2 = parse_int(argv[i + 3]);
+
+		case 3:
+			skip1 = parse_int(argv[i + 2]);
+
+		case 2:
+			fp2 = file_open(argv[i + 1]);
+
+		case 1:
+			fp1 = file_open(argv[i]);
+			break;
+
+		default:
+			return 1;
+	}
+
+	if (skip1 && fseek(fp1, skip1, SEEK_SET) < 0) {
+		if (!s_flag)
+			fprintf(stderr, "cmp: %s\n", strerror(errno));
+
+		return 1;
+	}
+
+	if (skip2 && fseek(fp2, skip2, SEEK_SET) < 0) {
+		if (!s_flag)
+			fprintf(stderr, "cmp: %s\n", strerror(errno));
+
+		return 1;
+	}
+
+	int ret = compare(fp1, fp2);
+	fclose(fp1);
+	fclose(fp2);
+
+	return ret;
+}
diff --git a/coreutils/du.c b/coreutils/du.c
index 8eda331..a8f191d 100644
--- a/coreutils/du.c
+++ b/coreutils/du.c
@@ -16,8 +16,10 @@ void print(double size, const char *filename) {
 	char c = 0;
 
 	if (h_flag) {
-		if (size < 1048576)
+		if (size < 1048576) {
+			size = size / 1024;
 			c = 'K';
+		}
 
 		else if (size < 1073741824) {
 			size = size / 1048576;
@@ -38,7 +40,7 @@ void print(double size, const char *filename) {
 	else if (m_flag)
 		size = size / 1048576;
 
-	printf("%.1f%c\t%s\n", size, c, filename);
+	printf("%.1f%c %s\n", size, c, filename);
 }
 
 double du(const char *path, int recurs_flag) {
diff --git a/obj/.gitignore b/obj/.gitignore
new file mode 100644
index 0000000..e69de29