diff --git a/build/phantom.js b/build/phantom.js
index 6b81ab8..469e866 100644
--- a/build/phantom.js
+++ b/build/phantom.js
@@ -1,30 +1,32 @@
-/* eslint-env node */
+/* eslint-env node, es6 */
 
 'use strict';
 
-var os = require('os');
-var glob = require('glob');
-var async = require('async');
-var qunit = require('node-qunit-phantomjs');
+const os = require('os');
+const glob = require('glob');
+const async = require('async');
+const qunit = require('node-qunit-phantomjs');
 
-var THREADS = os.cpus().length <= 2 ? 1 : os.cpus().length / 2;
+const cpus = os.cpus().length;
+const THREADS = cpus <= 2 ? 1 : cpus / 2;
 
-var ignores = [
+const ignore = [
     'test/fixtures/jquery/missing.html',
     'test/fixtures/jquery/and_bs_js_both_missing.html',
     'test/fixtures/charset/not-utf8.html'
 ];
 
-glob('test/fixtures/**/*.html', {ignore: ignores}, function (err, files) {
+glob('test/fixtures/**/*.html', {ignore}, (err, files) => {
     if (err) {
         throw err;
     }
 
     async.eachLimit(files,
         THREADS,
-        function (file, callback) {
+        (file, callback) => {
             qunit(file, {timeout: 10}, callback);
-        }, function (er) {
+        },
+        (er) => {
             if (er) {
                 throw er;
             }
diff --git a/build/stamp.js b/build/stamp.js
index c150f27..80a104a 100644
--- a/build/stamp.js
+++ b/build/stamp.js
@@ -1,28 +1,22 @@
-/* This file is taken from <https://github.com/twbs/bootstrap/blob/v4-dev/build/stamp.js>
-   and adapted for Bootlint.
- */
+// This file is taken from Bootstrap and adapted for Bootlint.
 
-/* eslint-env node */
+/* eslint-env node, es6 */
 
 'use strict';
 
-var fs = require('fs');
+const path = require('path');
+const pkg  = require(path.resolve('package.json'));
+const year = new Date().getFullYear();
 
-fs.readFile('package.json', function (err, data) {
-    if (err) {
-        throw err;
-    }
+const stampTop =
+`/*!
+ * Bootlint v${pkg.version} (${pkg.homepage})
+ * ${pkg.description}
+ * Copyright (c) 2014-${year} The Bootlint Authors
+ * Licensed under the MIT License (https://github.com/twbs/bootlint/blob/master/LICENSE).
+ */
 
-    var pkg = JSON.parse(data);
-    var year = new Date().getFullYear();
+`;
 
-    var stampTop = '/*!\n * Bootlint v' + pkg.version + ' (' + pkg.homepage + ')\n' +
-            ' * ' + pkg.description + '\n' +
-            ' * Copyright (c) 2014-' + year + ' The Bootlint Authors\n' +
-            ' * Licensed under the MIT License (https://github.com/twbs/bootlint/blob/master/LICENSE).\n' +
-            ' */\n';
-
-    process.stdout.write(stampTop);
-
-    process.stdin.pipe(process.stdout);
-});
+process.stdout.write(stampTop);
+process.stdin.pipe(process.stdout);