diff --git a/src/cat.c b/src/cat.c
new file mode 100644
index 0000000..f4d3f13
--- /dev/null
+++ b/src/cat.c
@@ -0,0 +1,41 @@
+#include <fcntl.h>
+#include <stdio.h>
+#include <errno.h>
+#include <string.h>
+#include <unistd.h>
+
+int cat(const int fd) {
+	char buf[4024];
+	ssize_t len;
+
+	while ((len = read(fd, buf, sizeof(buf))) > 0)
+		if (write(STDOUT_FILENO, buf, len) != len)
+			return 1;
+
+	return 0;
+}
+
+int main(const int argc, const char **argv) {
+	if (argc == 1)
+		return cat(STDIN_FILENO);
+
+	else {
+		for (int i = 1; i < argc; i++) {
+			int fd = open(argv[i], O_RDONLY);
+			if (fd < 0) {
+				fprintf(stderr, "cat: %s %s\n", argv[i], strerror(errno));
+				return 1;
+			}
+
+			if (cat(fd))
+				return 1;
+
+			if (close(fd)) {
+				fprintf(stderr, "cat: %s %s\n", argv[i], strerror(errno));
+				return 1;
+			}
+		}
+	}
+
+	return 0;
+}
diff --git a/src/echo.c b/src/echo.c
new file mode 100644
index 0000000..e4fe93a
--- /dev/null
+++ b/src/echo.c
@@ -0,0 +1,14 @@
+#include <stdio.h>
+
+int main(const int argc, const char **argv) {
+	if (argc > 1) {
+		for (int i = 1; i < argc; i++) {
+			fputs(argv[i], stdout);
+			if (i < argc - 1)
+				putchar(' ');
+		}
+	}
+
+	putchar('\n');
+	return 0;
+}
diff --git a/src/getloadavg.c b/src/getloadavg.c
new file mode 100644
index 0000000..ba7015d
--- /dev/null
+++ b/src/getloadavg.c
@@ -0,0 +1,15 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+int main(void) {
+	double avg[3] = {0, 0, 0};
+
+#ifndef __ANDROID__
+	if (getloadavg(avg, sizeof(avg) / sizeof(avg[0])) < 0) {
+		fprintf(stderr, "getloadavg: getloadavg() failed\n");
+		return 1;
+	}
+#endif
+
+	printf("%.2f %.2f %.2f\n", avg[0], avg[1], avg[2]);
+}
diff --git a/src/ls.c b/src/ls.c
new file mode 100644
index 0000000..4b78cb9
--- /dev/null
+++ b/src/ls.c
@@ -0,0 +1,74 @@
+#include <stdio.h>
+#include <errno.h>
+#include <string.h>
+#include <dirent.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+
+int list(const char *path, int flag, int label) {
+	struct stat statbuf;
+	if (stat(path, &statbuf)) {
+		fprintf(stderr, "unable to stat %s: %s\n", path, strerror(errno));
+		return 1;
+	}
+
+	/* If its file */
+	if (!S_ISDIR(statbuf.st_mode)) {
+		puts(path);
+		return 0;
+	}
+
+	/* Make label */
+	if (label)
+		printf("\n%s: \n", path);
+
+	/* Open and print dir */
+	struct dirent *ep;
+	DIR *dp = opendir(path);
+	if (dp == NULL) {
+		fprintf(stderr, "%s: %s\n", path, strerror(errno));
+		return 1;
+	}
+
+	while ((ep = readdir(dp)) != NULL) {
+		if (ep->d_name[0] == '.' && !flag)
+			continue;
+
+		puts(ep->d_name);
+	}
+
+	closedir(dp);
+	return 0;
+}
+
+
+
+int main(const int argc, const char **argv) {
+	int flag = 0;
+
+	int i;
+	for (i = 1; i < argc; i++) {
+		if (argv[i][0] != '-')
+			break;
+
+		else if (!strcmp(argv[i], "-a"))
+			flag = 1;
+
+		else if (!strcmp(argv[i], "-h")) {
+			printf("ls [-a] [Path]\n");
+			return 0;
+		}
+	}
+
+	if (i == argc)
+		return list(".", flag, 0);
+
+	if (i == argc - 1)
+		return list(argv[i], flag, 0);
+
+	else
+		for (int i = 1; i < argc; i++)
+			if (list(argv[i], flag, 1))
+				return 1;
+	return 0;
+}
diff --git a/src/pwd.c b/src/pwd.c
new file mode 100644
index 0000000..9b2068b
--- /dev/null
+++ b/src/pwd.c
@@ -0,0 +1,19 @@
+#include <stdio.h>
+#include <unistd.h>
+#include <string.h>
+#include <limits.h>
+#include <errno.h>
+
+int main(void) {
+	char cwd[PATH_MAX];
+
+	if (getcwd(cwd, sizeof(cwd)))
+		puts(cwd);
+
+	else {
+		fprintf(stderr, "pwd: %s\n", strerror(errno));
+		return 1;
+	}
+
+	return 0;
+}