diff --git a/index.js b/index.js
index eb667ed..f73c803 100755
--- a/index.js
+++ b/index.js
@@ -4,42 +4,42 @@ const fs = require('fs')
 const path = require('path')
 const glob = require('glob')
 const toc = require('markdown-toc')
-const inflection = require('inflection')
+
 const dir = process.argv[2]
+const index = process.argv[3]
 
 if (!dir) {
-  console.log('\nUsage: \nmarkdown-index directory/fulla/markdowns\n')
+  console.log('\nUsage: \nmarkdown-index directory/full/of/markdowns\n')
   process.exit(1)
 }
 
-glob(dir + '/**/*.md', function (err, files) {
+glob(`${dir}/**/*.md`, (err, files) => {
   if (err) throw err
-  var tables = files.map(function (file) {
+  const tables = files.map(file => {
     if (file.match('index.md')) return
     if (file.match('README.md')) return
     if (file.match('node_modules')) return
 
-    var filenameSlug = toc.slugify(path.parse(file).name)
-    var originalLinkify = toc.linkify
-    var table = toc(fs.readFileSync(file, 'utf8'), {
-      filter: function(str, ele, arr) {
-        // Skip top-level elements if their slug matches a slug of the filename.
-        return ele.level != 1 || ele.slug != filenameSlug
-      },
-      linkify: function(tok, text, slug, opts) {
+    const filenameSlug = toc.slugify(path.parse(file).name)
+    const originalLinkify = toc.linkify
+    const table = toc(fs.readFileSync(file, 'utf8'), {
+      filter: (str, ele, arr) => ele.level !== 1 || ele.slug !== filenameSlug, // Skip top-level elements if their slug matches a slug of the filename.
+      linkify: (tok, text, slug, opts) => {
         // Use empty options arg to avoid infinite recursion.
-        var tok = originalLinkify(tok, text, slug, {})
+        const newTok = originalLinkify(tok, text, slug, {})
         // Prepend filename to links.
-        tok.content = tok.content.replace('#', file + '#')
-        return tok
+        newTok.content = newTok.content.replace('#', `${file}#`)
+        return newTok
       }
     })
 
     // Add filename as a heading.
-    return '### [' + filenameSlug + '](' + file + ')\n\n' + table.content
+    return `#### [${path.parse(file).name}](${file})\n${table.content}\n`
   })
 
-  process.stdout.write(tables.join('\n\n'))
-  return tables.join('\n\n')
+  if (index) {
+    fs.writeFile(index, tables.join(''), 'utf8', err => (err ? console.log(err) : null))
+  } else {
+    process.stdout.write(tables.join('\n'))
+  }
 })
-