diff --git a/.gitignore b/.gitignore
index ab96a23..56ba81a 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,4 +3,4 @@
 .DS_Store
 node_modules
 npm-debug.log
-localtest.html
+/*.test.*
diff --git a/.jshintignore b/.jshintignore
index a76422d..54c5705 100644
--- a/.jshintignore
+++ b/.jshintignore
@@ -1,3 +1,5 @@
 Gruntfile.js
 dist/**/*.js
 build/**/*.js
+src/options.js
+bin/*
diff --git a/Gruntfile.js b/Gruntfile.js
index 5b5eee7..10f0729 100644
--- a/Gruntfile.js
+++ b/Gruntfile.js
@@ -20,6 +20,7 @@ module.exports = function (grunt) {
       },
       dist: {
         src: [
+          'src/options.js',
           'src/showdown.js',
           'src/helpers.js',
           'src/converter.js',
diff --git a/bin/showdown.js b/bin/showdown.js
new file mode 100644
index 0000000..4bacdaa
Binary files /dev/null and b/bin/showdown.js differ
diff --git a/dist/showdown.js b/dist/showdown.js
index 4e3bac8..c0b4286 100644
Binary files a/dist/showdown.js and b/dist/showdown.js differ
diff --git a/dist/showdown.js.map b/dist/showdown.js.map
index f7627e7..d3c0eb2 100644
Binary files a/dist/showdown.js.map and b/dist/showdown.js.map differ
diff --git a/dist/showdown.min.js b/dist/showdown.min.js
index 82dd554..c1bbb78 100644
Binary files a/dist/showdown.min.js and b/dist/showdown.min.js differ
diff --git a/dist/showdown.min.js.map b/dist/showdown.min.js.map
index c0b8fa1..549457e 100644
Binary files a/dist/showdown.min.js.map and b/dist/showdown.min.js.map differ
diff --git a/package.json b/package.json
index 71675e6..cf4093b 100644
--- a/package.json
+++ b/package.json
@@ -36,7 +36,7 @@
     "test": "grunt test"
   },
   "bin": {
-    "showdown": "src/cli.js"
+    "showdown": "bin/showdown.js"
   },
   "devDependencies": {
     "chai": "^1.10.0",
@@ -53,5 +53,8 @@
     "quiet-grunt": "^0.2.3",
     "sinon": "^1.14.1",
     "source-map-support": "^0.2.9"
+  },
+  "dependencies": {
+    "yargs": "^3.15.0"
   }
 }
diff --git a/src/cli.js b/src/cli.js
deleted file mode 100644
index 0b78b77..0000000
--- a/src/cli.js
+++ /dev/null
@@ -1,23 +0,0 @@
-var Showdown = require('./showdown');
-var cli = require('cli');
-var fs = require('fs');
-
-var converter = new Showdown.converter();
-
-/*
-If an argument is given, treat it as the file to be read.
-Otherwise, read from stdin.
-*/
-if(process.argv.length > 2) {
-    fs.readFile(process.argv[2], function(err, data) {
-        if(err) {
-            console.error("Error: Invalid file");
-        } else {
-            console.log(converter.makeHtml(data.toString()));
-        }
-    })
-} else {
-    cli.withStdin(function(data) {
-        this.output(converter.makeHtml(data.toString()));
-    })
-}
diff --git a/src/cli/cli.js b/src/cli/cli.js
new file mode 100644
index 0000000..7cd8dc4
--- /dev/null
+++ b/src/cli/cli.js
@@ -0,0 +1,30 @@
+'use strict';
+
+var version = require('../../package.json').version,
+    yargs = require('yargs');
+
+yargs
+  .version(version, 'v')
+  .alias('v', 'version')
+  .option('h', {
+    alias: 'help',
+    description: 'Show help'
+  })
+  .usage('Usage: showdown <command> [options]')
+  .demand(1, 'You must provide a valid command')
+  .command('makehtml', 'Converts markdown into html')
+  .example('showdown makehtml -i foo.md -o bar.html', 'Converts \'foo.md\' to \'bar.html\'')
+  .wrap(yargs.terminalWidth());
+
+var argv = yargs.argv,
+  command = argv._[0];
+if (command === 'makehtml') {
+  require('./makehtml.cmd.js').run();
+} else {
+  yargs.showHelp();
+}
+
+if (argv.help) {
+  yargs.showHelp();
+}
+process.exit(0);
diff --git a/src/cli/errorexit.js b/src/cli/errorexit.js
new file mode 100644
index 0000000..ea25eff
--- /dev/null
+++ b/src/cli/errorexit.js
@@ -0,0 +1,6 @@
+module.exports = exports = function errorExit(e) {
+  'use strict';
+  console.error('ERROR: ' + e.message);
+  console.error('Run \'showdown <command> -h\' for help');
+  process.exit(1);
+};
diff --git a/src/cli/makehtml.cmd.js b/src/cli/makehtml.cmd.js
new file mode 100644
index 0000000..acaf359
--- /dev/null
+++ b/src/cli/makehtml.cmd.js
@@ -0,0 +1,123 @@
+var yargs = require('yargs'),
+    fs = require('fs'),
+    errorExit = require('./errorexit.js'),
+    showdown = require('../../dist/showdown');
+
+yargs.reset()
+  .usage('Usage: showdown makehtml [options]')
+  .example('showdown makehtml -i', 'Reads from stdin and outputs to stdout')
+  .example('showdown makehtml -i foo.md -o bar.html', 'Reads \'foo.md\' and writes to \'bar.html\'')
+  //.demand(['i'])
+  .option('i', {
+    alias : 'input',
+    describe: 'Input source. Usually a md file. If omitted or empty, reads from stdin',
+    type: 'string'
+  })
+  .option('o', {
+    alias : 'output',
+    describe: 'Output target. Usually a html file. If omitted or empty, writes to stdout',
+    type: 'string',
+    default: false
+  })
+  .option('u', {
+    alias : 'encoding',
+    describe: 'Input encoding',
+    type: 'string'
+  })
+  .option('a', {
+    alias : 'append',
+    describe: 'Append data to output instead of overwriting',
+    type: 'string'
+  })
+  .option('e', {
+    alias : 'extensions',
+    describe: 'Load the specified extensions. Should be valid paths to node compatible extensions',
+    type: 'array'
+  })
+  .config('c')
+  .alias('c', 'config')
+  .help('h')
+  .alias('h', 'help');
+
+yargs.options(showdown.getDefaultOptions(false));
+argv = yargs.argv;
+
+function run() {
+  'use strict';
+  var input = '',
+    enc = 'utf8',
+    output;
+
+  if (argv.encoding) {
+    enc = argv.encoding;
+  }
+
+  // to avoid passing extensions to converter
+  delete argv.extensions;
+  var converter = new showdown.Converter(argv);
+
+  // Load extensions
+  if (argv.e) {
+    for (var i = 0; i < argv.e.length; ++i) {
+      loadExtension(argv.e[i], converter);
+    }
+  }
+
+  if (!argv.i || argv.i === '') {
+    // 'i' is undefined or empty, read from stdin
+    try {
+      var size = fs.fstatSync(process.stdin.fd).size;
+      input = size > 0 ? fs.readSync(process.stdin.fd, size)[0] : '';
+    } catch (e) {
+      var err = new Error('Could not read from stdin, reason: ' + e.message);
+      errorExit(err);
+    }
+  } else {
+    // 'i' has a value, read from file
+    try {
+      input = fs.readFileSync(argv.i, enc);
+    } catch (err) {
+      errorExit(err);
+    }
+  }
+
+  // parse and convert file
+  output = converter.makeHtml(input);
+
+  // Write output
+  if (!argv.o || argv.o === '') {
+    // o is undefined or empty, write to stdout
+    process.stdout.write(output);
+    // we won't print anything since it would conspurcate stdout and,
+    // consequently, the outputted file
+  } else {
+    // o is has a value, presumably a file, write to it.
+
+    // If a flag is passed, it means we should append instead of overwriting.
+    // Only works with files, obviously
+    var write = (argv.a) ? fs.appendFileSync : fs.writeFileSync;
+
+    try {
+      write(argv.o, output);
+    } catch (err) {
+      errorExit(err);
+    }
+    console.error('DONE!');
+  }
+}
+
+function loadExtension(path, converter) {
+  'use strict';
+  var ext;
+  try {
+    ext = require(path);
+    converter.addExtension(ext, path);
+  } catch (e) {
+    console.error('Could not load extension ' + path + '. Reason:');
+    console.error(e.message);
+  }
+}
+
+module.exports = exports = {
+  run: run
+};
diff --git a/src/converter.js b/src/converter.js
index 551aeb2..55ecb44 100644
--- a/src/converter.js
+++ b/src/converter.js
@@ -86,13 +86,16 @@ showdown.Converter = function (converterOptions) {
   /**
    * Parse extension
    * @param {*} ext
+   * @param {string} [name='']
    * @private
    */
-  function _parseExtension(ext) {
+  function _parseExtension(ext, name) {
 
+    name = name || null;
     // If it's a string, the extension was previously loaded
     if (showdown.helper.isString(ext)) {
       ext = showdown.helper.stdExtName(ext);
+      name = ext;
 
       // LEGACY_SUPPORT CODE
       if (showdown.extensions[ext]) {
@@ -118,8 +121,9 @@ showdown.Converter = function (converterOptions) {
       ext = [ext];
     }
 
-    if (!showdown.validateExtension(ext)) {
-      return;
+    var validExt = validate(ext, name);
+    if (!validExt.valid) {
+      throw Error(validExt.error);
     }
 
     for (var i = 0; i < ext.length; ++i) {
@@ -272,9 +276,11 @@ showdown.Converter = function (converterOptions) {
   /**
    * Add extension to THIS converter
    * @param {{}} extension
+   * @param {string} [name=null]
    */
-  this.addExtension = function (extension) {
-    _parseExtension(extension);
+  this.addExtension = function (extension, name) {
+    name = name || null;
+    _parseExtension(extension, name);
   };
 
   /**
diff --git a/src/options.js b/src/options.js
new file mode 100644
index 0000000..0f11c72
--- /dev/null
+++ b/src/options.js
@@ -0,0 +1,80 @@
+/**
+ * Created by Tivie on 13-07-2015.
+ */
+
+function getDefaultOpts(simple) {
+  'use strict';
+
+  var defaultOptions = {
+    omitExtraWLInCodeBlocks: {
+      default: false,
+      describe: 'Omit the default extra whiteline added to code blocks',
+      type: 'boolean'
+    },
+    noHeaderId: {
+      default: false,
+      describe: 'Turn on/off generated header id',
+      type: 'boolean'
+    },
+    prefixHeaderId: {
+      default: false,
+      describe: 'Specify a prefix to generated header ids',
+      type: 'string'
+    },
+    headerLevelStart: {
+      default: false,
+      describe: 'The header blocks level start',
+      type: 'integer'
+    },
+    parseImgDimensions: {
+      default: false,
+      describe: 'Turn on/off image dimension parsing',
+      type: 'boolean'
+    },
+    simplifiedAutoLink: {
+      default: false,
+      describe: 'Turn on/off GFM autolink style',
+      type: 'boolean'
+    },
+    literalMidWordUnderscores: {
+      default: false,
+      describe: 'Parse midword underscores as literal underscores',
+      type: 'boolean'
+    },
+    strikethrough: {
+      default: false,
+      describe: 'Turn on/off strikethrough support',
+      type: 'boolean'
+    },
+    tables: {
+      default: false,
+      describe: 'Turn on/off tables support',
+      type: 'boolean'
+    },
+    tablesHeaderId: {
+      default: false,
+      describe: 'Add an id to table headers',
+      type: 'boolean'
+    },
+    ghCodeBlocks: {
+      default: true,
+      describe: 'Turn on/off GFM fenced code blocks support',
+      type: 'boolean'
+    },
+    tasklists: {
+      default: false,
+      describe: 'Turn on/off GFM tasklist support',
+      type: 'boolean'
+    }
+  };
+  if (simple === false) {
+    return JSON.parse(JSON.stringify(defaultOptions));
+  }
+  var ret = {};
+  for (var opt in defaultOptions) {
+    if (defaultOptions.hasOwnProperty(opt)) {
+      ret[opt] = defaultOptions[opt].default;
+    }
+  }
+  return ret;
+}
diff --git a/src/showdown.js b/src/showdown.js
index 9d1880c..1ee2ee0 100644
--- a/src/showdown.js
+++ b/src/showdown.js
@@ -6,21 +6,7 @@
 var showdown = {},
     parsers = {},
     extensions = {},
-    defaultOptions = {
-      omitExtraWLInCodeBlocks:   false,
-      prefixHeaderId:            false,
-      noHeaderId:                false,
-      headerLevelStart:          1,
-      parseImgDimensions:        false,
-      simplifiedAutoLink:        false,
-      literalMidWordUnderscores: false,
-      strikethrough:             false,
-      tables:                    false,
-      tablesHeaderId:            false,
-      ghCodeBlocks:              true,  // true due to historical reasons
-      tasklists:                 false
-    },
-    globalOptions = JSON.parse(JSON.stringify(defaultOptions)),
+    globalOptions = getDefaultOpts(true),
     flavor = {
       github: {
         omitExtraWLInCodeBlocks:   true,
@@ -33,7 +19,7 @@ var showdown = {},
         ghCodeBlocks:              true,
         tasklists:                 true
       },
-      vanilla: JSON.parse(JSON.stringify(defaultOptions))
+      vanilla: getDefaultOpts(true)
     };
 
 /**
@@ -88,7 +74,7 @@ showdown.getOptions = function () {
  */
 showdown.resetOptions = function () {
   'use strict';
-  globalOptions = JSON.parse(JSON.stringify(defaultOptions));
+  globalOptions = getDefaultOpts(true);
 };
 
 /**
@@ -110,11 +96,12 @@ showdown.setFlavor = function (name) {
 /**
  * Get the default options
  * @static
+ * @param {boolean} [simple=true]
  * @returns {{}}
  */
-showdown.getDefaultOptions = function () {
+showdown.getDefaultOptions = function (simple) {
   'use strict';
-  return defaultOptions;
+  return getDefaultOpts(simple);
 };
 
 /**
@@ -233,7 +220,7 @@ function validate(extension, name) {
   }
 
   for (var i = 0; i < extension.length; ++i) {
-    var baseMsg = errMsg + 'sub-extension ' + i + ': ',
+    var baseMsg = errMsg + ' sub-extension ' + i + ': ',
         ext = extension[i];
     if (typeof ext !== 'object') {
       ret.valid = false;
diff --git a/src/subParsers/headers.js b/src/subParsers/headers.js
index a564d1c..811a493 100644
--- a/src/subParsers/headers.js
+++ b/src/subParsers/headers.js
@@ -1,7 +1,8 @@
 showdown.subParser('headers', function (text, options, globals) {
   'use strict';
 
-  var prefixHeader = options.prefixHeaderId;
+  var prefixHeader = options.prefixHeaderId,
+      headerLevelStart = (isNaN(parseInt(options.headerLevelStart))) ? 1 : parseInt(options.headerLevelStart);
 
   // Set text-style headers:
   //	Header 1
@@ -14,7 +15,7 @@ showdown.subParser('headers', function (text, options, globals) {
 
     var spanGamut = showdown.subParser('spanGamut')(m1, options, globals),
         hID = (options.noHeaderId) ? '' : ' id="' + headerId(m1) + '"',
-        hLevel = parseInt(options.headerLevelStart),
+        hLevel = headerLevelStart,
         hashBlock = '<h' + hLevel + hID + '>' + spanGamut + '</h' + hLevel + '>';
     return showdown.subParser('hashBlock')(hashBlock, options, globals);
   });
@@ -22,7 +23,7 @@ showdown.subParser('headers', function (text, options, globals) {
   text = text.replace(/^(.+)[ \t]*\n-+[ \t]*\n+/gm, function (matchFound, m1) {
     var spanGamut = showdown.subParser('spanGamut')(m1, options, globals),
         hID = (options.noHeaderId) ? '' : ' id="' + headerId(m1) + '"',
-        hLevel = parseInt(options.headerLevelStart) + 1,
+        hLevel = headerLevelStart + 1,
       hashBlock = '<h' + hLevel + hID + '>' + spanGamut + '</h' + hLevel + '>';
     return showdown.subParser('hashBlock')(hashBlock, options, globals);
   });
@@ -49,7 +50,7 @@ showdown.subParser('headers', function (text, options, globals) {
   text = text.replace(/^(#{1,6})[ \t]*(.+?)[ \t]*#*\n+/gm, function (wholeMatch, m1, m2) {
     var span = showdown.subParser('spanGamut')(m2, options, globals),
         hID = (options.noHeaderId) ? '' : ' id="' + headerId(m2) + '"',
-        hLevel = parseInt(options.headerLevelStart) - 1 + m1.length,
+        hLevel = headerLevelStart - 1 + m1.length,
         header = '<h' + hLevel + hID + '>' + span + '</h' + hLevel + '>';
 
     return showdown.subParser('hashBlock')(header, options, globals);
diff --git a/test/cli/basic.html b/test/cli/basic.html
new file mode 100644
index 0000000..a014504
--- /dev/null
+++ b/test/cli/basic.html
@@ -0,0 +1,3 @@
+<h1 id="sometitle">some title</h1>
+
+<p>Test <strong>bold</strong> and <em>italic</em></p>
diff --git a/test/cli/basic.md b/test/cli/basic.md
new file mode 100644
index 0000000..a5256ad
--- /dev/null
+++ b/test/cli/basic.md
@@ -0,0 +1,3 @@
+# some title
+
+Test **bold** and _italic_
diff --git a/test/node/cli.js b/test/node/cli.js
new file mode 100644
index 0000000..84bae88
--- /dev/null
+++ b/test/node/cli.js
@@ -0,0 +1,13 @@
+var execSync = require('child_process').execSync;
+
+describe('showdown cli', function () {
+  'use strict';
+  it('basic stdin stdout', function () {
+    var otp = execSync('showdown makehtml', {
+      encoding: 'utf8',
+      input: '**foo**'
+    });
+    otp.trim().should.equal('<p><strong>foo</strong></p>');
+  });
+});
+
diff --git a/test/node/showdown.js b/test/node/showdown.js
index db28ea7..3d89766 100644
--- a/test/node/showdown.js
+++ b/test/node/showdown.js
@@ -17,6 +17,8 @@ describe('showdown.options', function () {
 
   describe('getDefaultOptions()', function () {
     it('should get default options', function () {
+      var opts = require('../optionswp').getDefaultOpts(true);
+      /*
       var opts = {
         omitExtraWLInCodeBlocks:   false,
         prefixHeaderId:            false,
@@ -31,6 +33,7 @@ describe('showdown.options', function () {
         ghCodeBlocks:              true,
         tasklists:                 false
       };
+      */
       expect(showdown.getDefaultOptions()).to.be.eql(opts);
     });
   });
diff --git a/test/optionswp.js b/test/optionswp.js
new file mode 100644
index 0000000..dd20264
--- /dev/null
+++ b/test/optionswp.js
@@ -0,0 +1,9 @@
+/* jshint ignore:start */
+var fs = require('fs'),
+    filedata;
+filedata = fs.readFileSync('src/options.js', 'utf8');
+eval(filedata);
+module.exports = {
+  getDefaultOpts: getDefaultOpts
+};
+/* jshint ignore:end */
diff --git a/test/single.test.wrapper.js b/test/single.test.wrapper.js
deleted file mode 100644
index 7a6a418..0000000
--- a/test/single.test.wrapper.js
+++ /dev/null
@@ -1,13 +0,0 @@
-/**
- * Created by Estevao on 10-07-2015.
- */
-/*
-var showdown = require('../dist/showdown.js'),
-  bootstrap = require('./bootstrap.js'),
-  assertion = bootstrap.assertion,
-  testsuite = bootstrap.getTestSuite('test/features/');
-
-describe('makeHtml() single test', function () {
-  'use strict';
-});
-*/