diff --git a/.editorconfig b/.editorconfig
new file mode 100644
index 0000000..ff33cbf
--- /dev/null
+++ b/.editorconfig
@@ -0,0 +1,8 @@
+root = true
+
+[*.c]
+indent_style = tab
+end_of_line = lf
+charset = utf-8
+trim_trailing_whitespace = true
+insert_final_newline = true
diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..b4b23c1
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,10 @@
+*.DS_STORE
+*.o
+*.log
+*.gcov
+*.gcda
+*.gcno
+binary
+test
+example
+coverage
diff --git a/.travis.yml b/.travis.yml
new file mode 100644
index 0000000..3216cf8
--- /dev/null
+++ b/.travis.yml
@@ -0,0 +1,9 @@
+language: c
+compiler:
+# - clang
+- gcc
+script: make run-test
+after_script: sudo pip install cpp-coveralls && make run-coverage && coveralls --exclude test.c
+
+notifications:
+  email: false
diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..b6f24b5
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,33 @@
+PREFIX ?= /usr/local
+
+SRC = cli.c deps/binary.c/binary.c
+
+OBJ_SRC = $(SRC:.c=.o)
+
+CFLAGS = -D_GNU_SOURCE -std=c99 -I deps/binary.c/
+
+LFLAGS = -Wall -Wno-format-y2k -W -Wstrict-prototypes \
+	-Wpointer-arith -Wreturn-type -Wcast-qual -Wwrite-strings -Wswitch \
+	-Wshadow -Wcast-align -Wbad-function-cast -Wchar-subscripts -Winline \
+	-Wnested-externs -Wredundant-decls
+
+binary: $(OBJ_SRC)
+	$(CC) $(OBJ_SRC) -o $@
+
+.SUFFIXES: .c .o
+.c.o:
+	$(CC) $< $(CFLAGS) $(LFLAGS) -c -o $@
+
+install: binary
+	cp -f binary $(PREFIX)/bin/binary
+
+uninstall:
+	rm -f $(PREFIX)/bin/binary
+
+run-test: binary
+	bash ./test.sh
+
+clean:
+	rm -f binary *.o deps/**/*.o *.gc{ov,da,no}
+
+.PHONY: clean run-test install uninstall
diff --git a/cli.c b/cli.c
new file mode 100644
index 0000000..2b03415
--- /dev/null
+++ b/cli.c
@@ -0,0 +1,81 @@
+//
+// See for more details:
+// https://github.com/abranhe/binary.c
+//
+// cli.c
+//
+// MIT licensed.
+// Copyright (c) Abraham Hernandez <abraham@abranhe.com>
+//
+
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include "binary.h"
+
+const char
+*show_help() {
+ return "\n\
+ An small library to work with binary numbers\n\n\
+ Usage:\n\n\
+   $ binary <option> <input> \n\n\
+ Options:\n\n\
+   -is, --is-binary   check if a number is binary\n\
+        --to-decimal  convert a binary number to decimal\n\
+        --to-binary  convert a decimal number to binary\n\
+   -v,  --version     output version number\n\
+   -h,  --help        output usage information\n\n\
+ Example:\n\n\
+   $ binary --is-binary 10101000\n\
+   true\n\
+   $ binary --to-decimal 1011\n\
+   7\n\n";
+}
+
+/* CLI. */
+int
+main(int argc, char **argv) {
+  char *a = argv[1];
+  char *b = argv[2];
+
+  if (argc == 2) {
+    if (!strcmp(a, "-v") || !strcmp(a, "--version")) {
+      printf("%s", "1.0.0\n");
+      return 0;
+    }
+
+    if (!strcmp(a, "-h") || !strcmp(a, "--help")) {
+			printf("%s", show_help());
+      return 0;
+    }
+  }
+
+	if (argc == 3) {
+		if (!strcmp(a, "-is") || !strcmp(a, "--is-binary")) {
+			char *pb;
+			is_binary(strtoll(b, &pb, 0))
+				? printf("binary\n")
+				: printf("non-binary\n");
+			return 0;
+		}
+
+		if (!strcmp(a, "--to-decimal")) {
+			char *pb;
+			printf("%ld\n", to_decimal(strtoll(b, &pb, 0)));
+			return 0;
+		}
+
+		if (!strcmp(a, "--to-binary")) {
+			char *pb;
+			printf("%lld\n", to_binary(strtol(b, &pb, 0)));
+			return 0;
+		}
+	}
+
+  if (argc != 3) {
+    fprintf(stderr, "\033[31mBinary expects two arguments.\n\033[0m\n");
+		fprintf(stderr, "\033[31mSee `--help` for more details.\033[0m\n");
+    return 1;
+  }
+  return 0;
+}
diff --git a/deps/binary.c/binary.c b/deps/binary.c/binary.c
new file mode 100644
index 0000000..136d4f3
--- /dev/null
+++ b/deps/binary.c/binary.c
@@ -0,0 +1,61 @@
+//
+// An small library to work with
+// binary numbers.
+//
+// binary.c
+//
+// MIT licensed.
+// Copyright (c) Abraham Hernandez <abraham@abranhe.com>
+//
+
+#include <stdbool.h>
+
+bool
+is_binary (long long binary) {
+	bool status = true;
+	while(true) {
+		if (binary == 0) break;
+		else {
+			int tmp = binary % 10;
+			if(tmp > 1) {
+				status = false;
+				break;
+			}
+			binary = binary / 10;
+		}
+	}
+	return status;
+}
+
+long
+to_decimal (long long binary) {
+	if(!is_binary(binary)) return -1;
+
+	int decimal = 0;
+	int multiplier = 1;
+
+	while (binary != 0) {
+		decimal += (binary % 10) * multiplier;
+		binary /= 10;
+		multiplier *= 2;
+	}
+	return decimal;
+}
+
+long long to_binary(long number) {
+	long long binary = 0;
+	int remainder;
+	int i = 1;
+
+	while (number != 0) {
+		remainder = number % 2;
+		number /= 2;
+		binary += remainder * i;
+		i *= 10;
+  }
+	return binary;
+}
+
+// TODO:
+// add_binary()
+// substract_binary() ...
diff --git a/deps/binary.c/binary.h b/deps/binary.c/binary.h
new file mode 100644
index 0000000..70bcb95
--- /dev/null
+++ b/deps/binary.c/binary.h
@@ -0,0 +1,29 @@
+#ifndef BINARY_H
+#define BINARY_H
+
+//
+// binary.h
+//
+// MIT licensed.
+// Copyright (c) Abraham Hernandez <abraham@abranhe.com>
+//
+
+#define bool int
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+bool
+is_binary(long binary);
+
+long
+to_decimal(long long binary);
+
+long long to_binary(long number);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif // BINARY_H
diff --git a/deps/binary.c/package.json b/deps/binary.c/package.json
new file mode 100644
index 0000000..af97db7
--- /dev/null
+++ b/deps/binary.c/package.json
@@ -0,0 +1,14 @@
+{
+  "name": "binary.c",
+  "version": "1.0.0",
+  "description": "An small library to work with binary numbers",
+  "license": "MIT",
+  "keywords": [
+    "binary", "binary-numbers"
+  ],
+  "repo": "abranhe/binary.c",
+  "src": [
+    "binary.h",
+    "binary.c"
+  ]
+}
diff --git a/license b/license
new file mode 100644
index 0000000..9146125
--- /dev/null
+++ b/license
@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) Abraham Hernandez <abraham@abranhe.com> (abranhe.com)
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
diff --git a/package.json b/package.json
new file mode 100644
index 0000000..f62e7a3
--- /dev/null
+++ b/package.json
@@ -0,0 +1,17 @@
+{
+  "name": "binary.c",
+  "version": "1.0.0",
+  "description": "An small library to work with binary numbers",
+  "license": "MIT",
+  "keywords": [
+    "binary",
+    "binary-numbers",
+    "bin",
+    "cli"
+  ],
+  "repo": "abranhe/binary.c",
+  "dependencies": {
+    "abranhe/binary.c": "1.0.0"
+  },
+  "install": "make install"
+}
diff --git a/readme.md b/readme.md
new file mode 100644
index 0000000..1463716
--- /dev/null
+++ b/readme.md
@@ -0,0 +1,80 @@
+<p align="center">
+	<br>
+	<img src="https://cdn.abranhe.com/projects/binary/logo.svg">
+	<br>
+	<br>
+	<b>binary cli</b>: The command line interface to work with binary numbers
+	<br>
+</p>
+
+<p align="center">
+	<a href="https://travis-ci.org/abranhe/binary"><img src="https://img.shields.io/travis/abranhe/binary.svg?logo=travis" /></a>
+	<a href="https://github.com/abranhe"><img src="https://abranhe.com/badge.svg"></a>
+	<a href="https://cash.me/$abranhe"><img src="https://cdn.abranhe.com/badges/cash-me.svg"></a>
+	<a href="https://patreon.com/abranhe"><img src="https://cdn.abranhe.com/badges/patreon.svg" /></a>
+	<a href="https://github.com/abranhe/binary/blob/master/license"><img src="https://img.shields.io/github/license/abranhe/binary.svg" /></a>
+
+  <br>
+  <br>
+</p>
+In mathematics and digital electronics, a binary number is a number expressed in the **base-2 numeral system** or **binary numeral system**, which uses only two symbols: typically `0` and `1`.
+
+
+## Installation
+
+*Installing using [Clib](https://github.com/clibs/clib)*
+
+```sh
+$ clib install abranhe/binary
+```
+
+## CLI
+
+*The options of binary*
+
+```
+An small library to work with binary numbers
+
+ Usage:
+
+   $ binary <option> <input>
+
+ Options:
+
+   -is, --is-binary   check if a number is binary
+        --to-decimal  convert a binary number to decimal
+        --to-binary  convert a decimal number to binary
+   -v,  --version     output version number
+   -h,  --help        output usage information
+
+ Example:
+
+   $ binary --is-binary 10101000
+   true
+   $ binary --to-decimal 1011
+   7
+```
+
+## Related
+
+- [binary.c][binary]: API for this module written in C.
+
+## Team
+
+|[![Carlos Abraham Logo][abranhe-img]][abranhe]|
+| :-: |
+| [Carlos Abraham][abranhe] |
+
+## License
+
+[MIT][license] License © [Carlos Abraham][abranhe]
+
+<!-------------------- Links ------------------------>
+[abranhe]: https://github.com/abranhe
+[abranhe-img]: https://avatars3.githubusercontent.com/u/21347264?s=50
+[license]: https://github.com/abranhe/binary/blob/master/license
+[travis-badge]: https://img.shields.io/travis/abranhe/binary.svg
+[travis-status]: https://travis-ci.org/abranhe/binary
+[coverage-badge]: https://img.shields.io/coveralls/abranhe/binary.svg
+[coverage-status]: https://coveralls.io/r/abranhe/binary?branch=master
+[binary]: https://github.com/abranhe/binary.c
diff --git a/test.sh b/test.sh
new file mode 100644
index 0000000..5ca5f26
--- /dev/null
+++ b/test.sh
@@ -0,0 +1,58 @@
+#!/bin/sh
+#!/bin/bash
+
+typeset -i tests=0
+
+function describe {
+  let tests+=1
+  description="$1"
+}
+
+function assert {
+  if [[ "$1" == "$2" ]]; then
+    printf "\033[32m.\033[0m"
+  else
+    printf "\033[31m\nFAIL: $description\033[0m: '$1' != '$2'\n"
+    exit 1
+  fi
+}
+
+describe "Help"
+  ./binary --help > /dev/null 2>&1
+  assert $? 0
+
+describe "Help: short flag"
+  ./binary -h > /dev/null 2>&1
+  assert $? 0
+
+describe "Version"
+  ./binary --version > /dev/null 2>&1
+  assert $? 0
+
+describe "Version: short flag"
+  ./binary -v > /dev/null 2>&1
+  assert $? 0
+
+describe "Execute: one argument"
+  ./binary foo > /dev/null 2>&1
+  assert $? 1
+
+describe "Execute: more than two arguments"
+  ./binary foo bar baz > /dev/null 2>&1
+  assert $? 1
+
+describe "Execute: should work"
+  assert `./binary "--to-binary" "7"` 111
+  assert `./binary "--to-binary" "19"` 10011
+  assert `./binary "--to-binary" "3"` 11
+
+  assert `./binary "--to-decimal" "111"` 7
+  assert `./binary "--to-decimal" "10011"` 19
+  assert `./binary "--to-decimal" "11"` 3
+
+  assert `./binary "-is" "111"` binary
+  assert `./binary "-is" "7777777"` non-binary
+
+printf "\033[32m\n(✓) Passed $tests assertions without errors\033[0m\n"
+
+exit 0