diff --git a/lib/_debugger.js b/lib/_debugger.js
index b8a3177d6877..9887f015550f 100644
--- a/lib/_debugger.js
+++ b/lib/_debugger.js
@@ -19,6 +19,8 @@
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
+'use strict';
+
 var util = require('util'),
     path = require('path'),
     net = require('net'),
diff --git a/lib/_http_agent.js b/lib/_http_agent.js
index 6fbff37d85db..96797b2e8228 100644
--- a/lib/_http_agent.js
+++ b/lib/_http_agent.js
@@ -19,6 +19,8 @@
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
+'use strict';
+
 var net = require('net');
 var util = require('util');
 var EventEmitter = require('events').EventEmitter;
diff --git a/lib/_http_client.js b/lib/_http_client.js
index 5f873d65d18c..0467faead1b8 100644
--- a/lib/_http_client.js
+++ b/lib/_http_client.js
@@ -19,6 +19,8 @@
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
+'use strict';
+
 var util = require('util');
 var net = require('net');
 var url = require('url');
diff --git a/lib/_http_common.js b/lib/_http_common.js
index 7994cdd98d92..8edc6713940c 100644
--- a/lib/_http_common.js
+++ b/lib/_http_common.js
@@ -19,6 +19,8 @@
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
+'use strict';
+
 var FreeList = require('freelist').FreeList;
 var HTTPParser = process.binding('http_parser').HTTPParser;
 
diff --git a/lib/_http_incoming.js b/lib/_http_incoming.js
index 69d3d86ec6a4..a252c114bf84 100644
--- a/lib/_http_incoming.js
+++ b/lib/_http_incoming.js
@@ -19,6 +19,8 @@
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
+'use strict';
+
 var util = require('util');
 var Stream = require('stream');
 
diff --git a/lib/_http_outgoing.js b/lib/_http_outgoing.js
index d02bdf7f23e0..7f61aac35eda 100644
--- a/lib/_http_outgoing.js
+++ b/lib/_http_outgoing.js
@@ -19,6 +19,8 @@
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
+'use strict';
+
 var assert = require('assert').ok;
 var Stream = require('stream');
 var timers = require('timers');
diff --git a/lib/_http_server.js b/lib/_http_server.js
index 787fc27bbf14..5927ed26893e 100644
--- a/lib/_http_server.js
+++ b/lib/_http_server.js
@@ -19,6 +19,8 @@
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
+'use strict';
+
 var util = require('util');
 var net = require('net');
 var EventEmitter = require('events').EventEmitter;
diff --git a/lib/_linklist.js b/lib/_linklist.js
index b73bbed22b8e..048e933ee3a7 100644
--- a/lib/_linklist.js
+++ b/lib/_linklist.js
@@ -19,6 +19,8 @@
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
+'use strict';
+
 function init(list) {
   list._idleNext = list;
   list._idlePrev = list;
diff --git a/lib/_stream_duplex.js b/lib/_stream_duplex.js
index 75cf30d79873..474a31303d97 100644
--- a/lib/_stream_duplex.js
+++ b/lib/_stream_duplex.js
@@ -19,6 +19,8 @@
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
+'use strict';
+
 // a duplex stream is just a stream that is both readable and writable.
 // Since JS doesn't have multiple prototypal inheritance, this class
 // prototypally inherits from Readable, and then parasitically from
diff --git a/lib/_stream_passthrough.js b/lib/_stream_passthrough.js
index a5e986430d79..7a9102aedc7e 100644
--- a/lib/_stream_passthrough.js
+++ b/lib/_stream_passthrough.js
@@ -19,6 +19,8 @@
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
+'use strict';
+
 // a passthrough stream.
 // basically just the most minimal sort of Transform stream.
 // Every written chunk gets output as-is.
diff --git a/lib/_stream_readable.js b/lib/_stream_readable.js
index 5f280b773601..08aad09d813e 100644
--- a/lib/_stream_readable.js
+++ b/lib/_stream_readable.js
@@ -19,6 +19,8 @@
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
+'use strict';
+
 module.exports = Readable;
 Readable.ReadableState = ReadableState;
 
diff --git a/lib/_stream_transform.js b/lib/_stream_transform.js
index 1843f51b7517..3c6bb9db9683 100644
--- a/lib/_stream_transform.js
+++ b/lib/_stream_transform.js
@@ -19,6 +19,8 @@
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
+'use strict';
+
 
 // a transform stream is a readable/writable stream where you do
 // something with the data.  Sometimes it's called a "filter",
diff --git a/lib/_stream_writable.js b/lib/_stream_writable.js
index f39393b06178..70da498da3e2 100644
--- a/lib/_stream_writable.js
+++ b/lib/_stream_writable.js
@@ -19,6 +19,8 @@
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
+'use strict';
+
 // A bit simpler than readable streams.
 // Implement an async ._write(chunk, cb), and it'll handle all
 // the drain event emission and buffering.
diff --git a/lib/_tls_common.js b/lib/_tls_common.js
index 72648be98433..113abbcc1f60 100644
--- a/lib/_tls_common.js
+++ b/lib/_tls_common.js
@@ -19,6 +19,8 @@
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
+'use strict';
+
 var util = require('util');
 var constants = require('constants');
 var tls = require('tls');
diff --git a/lib/_tls_legacy.js b/lib/_tls_legacy.js
index 9401fc559ad5..2243394778d3 100644
--- a/lib/_tls_legacy.js
+++ b/lib/_tls_legacy.js
@@ -19,6 +19,8 @@
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
+'use strict';
+
 var assert = require('assert');
 var events = require('events');
 var stream = require('stream');
diff --git a/lib/_tls_wrap.js b/lib/_tls_wrap.js
index 6e2a430840a9..f4ee762eed4d 100644
--- a/lib/_tls_wrap.js
+++ b/lib/_tls_wrap.js
@@ -22,6 +22,8 @@
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
+'use strict';
+
 var assert = require('assert');
 var crypto = require('crypto');
 var net = require('net');
diff --git a/lib/assert.js b/lib/assert.js
index 357dd1bb0c6e..58f320d68364 100644
--- a/lib/assert.js
+++ b/lib/assert.js
@@ -22,6 +22,8 @@
 // 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.
 
+'use strict';
+
 // UTILITY
 var util = require('util');
 var b = require('buffer');
diff --git a/lib/buffer.js b/lib/buffer.js
index 9b43882e574d..4604ba9898ef 100644
--- a/lib/buffer.js
+++ b/lib/buffer.js
@@ -19,6 +19,8 @@
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
+'use strict';
+
 var buffer = process.binding('buffer');
 var smalloc = process.binding('smalloc');
 var util = require('util');
diff --git a/lib/child_process.js b/lib/child_process.js
index b4a8894734b8..657e065dce65 100644
--- a/lib/child_process.js
+++ b/lib/child_process.js
@@ -19,6 +19,8 @@
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
+'use strict';
+
 var StringDecoder = require('string_decoder').StringDecoder;
 var EventEmitter = require('events').EventEmitter;
 var net = require('net');
diff --git a/lib/cluster.js b/lib/cluster.js
index 71ebf41c454e..e05de4568bc6 100644
--- a/lib/cluster.js
+++ b/lib/cluster.js
@@ -19,6 +19,8 @@
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
+'use strict';
+
 var EventEmitter = require('events').EventEmitter;
 var assert = require('assert');
 var dgram = require('dgram');
diff --git a/lib/console.js b/lib/console.js
index a3c8acb5940b..00e6f315d9e2 100644
--- a/lib/console.js
+++ b/lib/console.js
@@ -19,6 +19,8 @@
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
+'use strict';
+
 var util = require('util');
 
 function Console(stdout, stderr) {
diff --git a/lib/constants.js b/lib/constants.js
index 1b87b2b2d0c6..816dc853e1bb 100644
--- a/lib/constants.js
+++ b/lib/constants.js
@@ -19,4 +19,6 @@
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
+'use strict';
+
 module.exports = process.binding('constants');
diff --git a/lib/crypto.js b/lib/crypto.js
index 97cceb67f5c4..8f80fff1594a 100644
--- a/lib/crypto.js
+++ b/lib/crypto.js
@@ -19,6 +19,8 @@
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
+'use strict';
+
 // Note: In 0.8 and before, crypto functions all defaulted to using
 // binary-encoded strings rather than buffers.
 
diff --git a/lib/dgram.js b/lib/dgram.js
index 764892a90bc4..385ffa288cdb 100644
--- a/lib/dgram.js
+++ b/lib/dgram.js
@@ -19,6 +19,8 @@
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
+'use strict';
+
 var assert = require('assert');
 var util = require('util');
 var events = require('events');
diff --git a/lib/dns.js b/lib/dns.js
index 18023fab1621..453497185213 100644
--- a/lib/dns.js
+++ b/lib/dns.js
@@ -19,6 +19,8 @@
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
+'use strict';
+
 var net = require('net');
 var util = require('util');
 
diff --git a/lib/domain.js b/lib/domain.js
index f2f9f43ae5af..127869435ddd 100644
--- a/lib/domain.js
+++ b/lib/domain.js
@@ -19,6 +19,8 @@
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
+'use strict';
+
 var util = require('util');
 var EventEmitter = require('events');
 var inherits = util.inherits;
diff --git a/lib/events.js b/lib/events.js
index 0cd841b8445a..f8c651feac69 100644
--- a/lib/events.js
+++ b/lib/events.js
@@ -19,6 +19,8 @@
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
+'use strict';
+
 var domain;
 var util = require('util');
 
diff --git a/lib/freelist.js b/lib/freelist.js
index 588facd25b39..561ca53458c2 100644
--- a/lib/freelist.js
+++ b/lib/freelist.js
@@ -19,6 +19,8 @@
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
+'use strict';
+
 // This is a free list to avoid creating so many of the same object.
 exports.FreeList = function(name, max, constructor) {
   this.name = name;
diff --git a/lib/fs.js b/lib/fs.js
index bd9fde680df8..cd961242da22 100644
--- a/lib/fs.js
+++ b/lib/fs.js
@@ -19,6 +19,8 @@
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
+'use strict';
+
 // Maintainers, keep in mind that octal literals are not allowed
 // in strict mode. Use the decimal value and add a comment with
 // the octal value. Example:
diff --git a/lib/http.js b/lib/http.js
index d12f12d60ceb..c0b2b0af1128 100644
--- a/lib/http.js
+++ b/lib/http.js
@@ -19,6 +19,8 @@
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
+'use strict';
+
 var util = require('util');
 var EventEmitter = require('events').EventEmitter;
 
diff --git a/lib/https.js b/lib/https.js
index f9011648fb69..4c2731ab581c 100644
--- a/lib/https.js
+++ b/lib/https.js
@@ -19,6 +19,8 @@
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
+'use strict';
+
 var tls = require('tls');
 var url = require('url');
 var http = require('http');
diff --git a/lib/module.js b/lib/module.js
index 4ac8cfa30a02..0f1f38c7bb0c 100644
--- a/lib/module.js
+++ b/lib/module.js
@@ -19,6 +19,8 @@
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
+'use strict';
+
 var NativeModule = require('native_module');
 var util = require('util');
 var runInThisContext = require('vm').runInThisContext;
diff --git a/lib/net.js b/lib/net.js
index 61cb4209522e..3fdc4580ece0 100644
--- a/lib/net.js
+++ b/lib/net.js
@@ -19,6 +19,8 @@
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
+'use strict';
+
 var events = require('events');
 var stream = require('stream');
 var timers = require('timers');
diff --git a/lib/os.js b/lib/os.js
index 814c054ef31a..79cef00a4ae5 100644
--- a/lib/os.js
+++ b/lib/os.js
@@ -19,6 +19,8 @@
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
+'use strict';
+
 var binding = process.binding('os');
 var util = require('util');
 var isWindows = process.platform === 'win32';
diff --git a/lib/path.js b/lib/path.js
index 27c148ab535f..849a82768d3d 100644
--- a/lib/path.js
+++ b/lib/path.js
@@ -19,6 +19,8 @@
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
+'use strict';
+
 
 var isWindows = process.platform === 'win32';
 var util = require('util');
diff --git a/lib/querystring.js b/lib/querystring.js
index 04c083d8abcd..0f317fc30b8e 100644
--- a/lib/querystring.js
+++ b/lib/querystring.js
@@ -19,6 +19,8 @@
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
+'use strict';
+
 // Query String Utilities
 
 var QueryString = exports;
diff --git a/lib/readline.js b/lib/readline.js
index fe2def0350a0..4676bccb3fb2 100644
--- a/lib/readline.js
+++ b/lib/readline.js
@@ -19,6 +19,8 @@
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
+'use strict';
+
 // Inspiration for this code comes from Salvatore Sanfilippo's linenoise.
 // https://github.com/antirez/linenoise
 // Reference:
diff --git a/lib/repl.js b/lib/repl.js
index a8fa060c5930..289aae4f040f 100644
--- a/lib/repl.js
+++ b/lib/repl.js
@@ -19,6 +19,8 @@
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
+'use strict';
+
 /* A repl library that you can include in your own code to get a runtime
  * interface to your program.
  *
diff --git a/lib/smalloc.js b/lib/smalloc.js
index 2b4175e0cb15..994b3f281bae 100644
--- a/lib/smalloc.js
+++ b/lib/smalloc.js
@@ -19,6 +19,8 @@
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
+'use strict';
+
 var smalloc = process.binding('smalloc');
 var kMaxLength = smalloc.kMaxLength;
 var util = require('util');
diff --git a/lib/stream.js b/lib/stream.js
index 073c6ed338fa..83815e840497 100644
--- a/lib/stream.js
+++ b/lib/stream.js
@@ -19,6 +19,8 @@
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
+'use strict';
+
 module.exports = Stream;
 
 var EE = require('events').EventEmitter;
diff --git a/lib/string_decoder.js b/lib/string_decoder.js
index fd11e51c8da8..84ac9a9d4453 100644
--- a/lib/string_decoder.js
+++ b/lib/string_decoder.js
@@ -19,6 +19,8 @@
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
+'use strict';
+
 function assertEncoding(encoding) {
   if (encoding && !Buffer.isEncoding(encoding)) {
     throw new Error('Unknown encoding: ' + encoding);
diff --git a/lib/sys.js b/lib/sys.js
index cf98a073e6cd..6dc415c31f86 100644
--- a/lib/sys.js
+++ b/lib/sys.js
@@ -19,6 +19,8 @@
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
+'use strict';
+
 // the sys module was renamed to 'util'.
 // this shim remains to keep old programs working.
 module.exports = require('util');
diff --git a/lib/timers.js b/lib/timers.js
index 5ef5f37ed763..68f87d7c9f3f 100644
--- a/lib/timers.js
+++ b/lib/timers.js
@@ -19,6 +19,8 @@
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
+'use strict';
+
 var Timer = process.binding('timer_wrap').Timer;
 var L = require('_linklist');
 var assert = require('assert').ok;
diff --git a/lib/tls.js b/lib/tls.js
index a00fbb9d722e..7aad494b1e0d 100644
--- a/lib/tls.js
+++ b/lib/tls.js
@@ -19,6 +19,8 @@
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
+'use strict';
+
 var net = require('net');
 var url = require('url');
 var util = require('util');
diff --git a/lib/tty.js b/lib/tty.js
index 74300fc1e4b8..3d5c2a664930 100644
--- a/lib/tty.js
+++ b/lib/tty.js
@@ -19,6 +19,8 @@
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
+'use strict';
+
 var inherits = require('util').inherits;
 var net = require('net');
 var TTY = process.binding('tty_wrap').TTY;
diff --git a/lib/url.js b/lib/url.js
index 07a6c103a474..c5a3793b9a9c 100644
--- a/lib/url.js
+++ b/lib/url.js
@@ -19,6 +19,8 @@
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
+'use strict';
+
 var punycode = require('punycode');
 var util = require('util');
 
diff --git a/lib/util.js b/lib/util.js
index e97820c9af37..4fed8311a090 100644
--- a/lib/util.js
+++ b/lib/util.js
@@ -19,6 +19,8 @@
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
+'use strict';
+
 var formatRegExp = /%[sdj%]/g;
 exports.format = function(f) {
   if (!isString(f)) {
diff --git a/lib/vm.js b/lib/vm.js
index 7c6c59c0af49..653c27c0d857 100644
--- a/lib/vm.js
+++ b/lib/vm.js
@@ -19,6 +19,8 @@
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
+'use strict';
+
 var binding = process.binding('contextify');
 var Script = binding.ContextifyScript;
 var util = require('util');
diff --git a/lib/zlib.js b/lib/zlib.js
index f80c9833a444..a85e8efb5181 100644
--- a/lib/zlib.js
+++ b/lib/zlib.js
@@ -19,6 +19,8 @@
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
+'use strict';
+
 var Transform = require('_stream_transform');
 
 var binding = process.binding('zlib');
diff --git a/src/node.js b/src/node.js
index 50460383ff71..02aee1708c4f 100644
--- a/src/node.js
+++ b/src/node.js
@@ -24,6 +24,9 @@
 // This file is invoked by node::Load in src/node.cc, and responsible for
 // bootstrapping the node.js core. Special caution is given to the performance
 // of the startup process, so many dependencies are invoked lazily.
+
+'use strict';
+
 (function(process) {
   this.global = this;
 
diff --git a/test/simple/test-use-strict-builtin-modules.js b/test/simple/test-use-strict-builtin-modules.js
index b4d89d0cfe5e..5172ae8cc9f9 100644
--- a/test/simple/test-use-strict-builtin-modules.js
+++ b/test/simple/test-use-strict-builtin-modules.js
@@ -27,27 +27,18 @@
 var child_process = require('child_process');
 var assert = require('assert');
 
-function getBuiltinModulesPath(builtinModuleFilename) {
-  return path.join(NODE_LIB_DIR, builtinModuleFilename);
-}
-
-function shouldBeTested(builtinModuleFilename) {
-  assert(typeof builtinModuleFilename === 'string',
-         'builtinModuleFilename must be a string');
-  assert(builtinModuleFilename.length > 0,
-         'builtinModuleFilename must be a non-empty string');
-
-  var isInternalModule = builtinModuleFilename.charAt(0) === '_';
-  if (isInternalModule || builtinModuleFilename === 'module.js') {
-    // Do not load "internal" modules as we don't care if they can
-    // be loaded with --use-strict, since they are not part of the
-    // public API.
-    //
-    // Do not load module.js because:
+function shouldBeTested(builtinModuleName) {
+  assert(typeof builtinModuleName === 'string',
+         'builtinModuleName must be a string');
+  assert(builtinModuleName.length > 0,
+         'builtinModuleName must be a non-empty string');
+
+  if (builtinModuleName === 'module') {
+    // Do not load 'module' because:
     // 1) It's loaded as part of the normal node.js startup process.
     // 2) Loading it twice is not supported since it requires
     // that NativeModule.require is the existing require implementation,
-    // but it overrides it when it's loaded.
+    // but it overrides it when it's loaded as part of node's bootstrap.
     return false;
   }
 
@@ -57,16 +48,6 @@ function shouldBeTested(builtinModuleFilename) {
 if (process.argv[2] !== 'child') {
   child_process.fork(__filename, ['child'], { execArgv: ['--use-strict']});
 } else {
-  var fs = require('fs');
-  var path = require('path');
-
-  var NODE_LIB_DIR = path.join(path.resolve(__dirname, '../..'), 'lib');
-
-  fs.readdir(NODE_LIB_DIR, function onDirRead(err, builtinModules) {
-    if (err) throw err;
-
-    var builtinModulesPaths = builtinModules.filter(shouldBeTested)
-                                            .map(getBuiltinModulesPath);
-    builtinModulesPaths.forEach(require);
-  });
+  var natives = process.binding('natives');
+  Object.keys(natives).filter(shouldBeTested).forEach(require);
 }