diff --git a/lib/coffee_script/command_line.js b/lib/coffee_script/command_line.js
index 15f1bfe9..9c3a47e1 100644
--- a/lib/coffee_script/command_line.js
+++ b/lib/coffee_script/command_line.js
@@ -1,6 +1,6 @@
 (function(){
-  var BANNER, SWITCHES, WATCH_INTERVAL, coffee, compile, compile_scripts, lint, option_parser, options, optparse, parse_options, path, posix, sources, usage, version, write_js;
-  posix = require('posix');
+  var BANNER, SWITCHES, WATCH_INTERVAL, coffee, compile, compile_scripts, fs, lint, option_parser, options, optparse, parse_options, path, sources, usage, version, write_js;
+  fs = require('fs');
   path = require('path');
   coffee = require('coffee-script');
   optparse = require('optparse');
@@ -66,7 +66,7 @@
       return null;
     }
     opts = options;
-    return posix.cat(source).addCallback(function(code) {
+    return fs.cat(source).addCallback(function(code) {
       var js;
       if (opts.tokens) {
         puts(coffee.print_tokens(coffee.tokenize(code)));
@@ -93,8 +93,8 @@
     filename = path.basename(source, path.extname(source)) + '.js';
     dir = options.output || path.dirname(source);
     js_path = path.join(dir, filename);
-    return posix.open(js_path, process.O_CREAT | process.O_WRONLY | process.O_TRUNC, parseInt('0755', 8)).addCallback(function(fd) {
-      return posix.write(fd, js);
+    return fs.open(js_path, process.O_CREAT | process.O_WRONLY | process.O_TRUNC, parseInt('0755', 8)).addCallback(function(fd) {
+      return fs.write(fd, js);
     });
   };
   // Pipe compiled JS through JSLint (requires a working 'jsl' command).
diff --git a/lib/coffee_script/grammar.js b/lib/coffee_script/grammar.js
index 9869356b..5df3b40c 100644
--- a/lib/coffee_script/grammar.js
+++ b/lib/coffee_script/grammar.js
@@ -1,5 +1,5 @@
 (function(){
-  var Parser, __a, __b, __c, __d, __e, __f, bnf, grammar, js, name, non_terminal, o, operators, option, parser, parser_path, part, posix, tokens, unwrap;
+  var Parser, __a, __b, __c, __d, __e, __f, bnf, fs, grammar, js, name, non_terminal, o, operators, option, parser, parser_path, part, tokens, unwrap;
   var __hasProp = Object.prototype.hasOwnProperty;
   Parser = require('jison').Parser;
   // DSL ===================================================================
@@ -555,9 +555,9 @@
   js = parser.generate();
   // Save the parser to a file.
   // puts parser.generate()
-  posix = require('posix');
+  fs = require('fs');
   parser_path = 'lib/coffee_script/parser.js';
-  posix.open(parser_path, process.O_CREAT | process.O_WRONLY | process.O_TRUNC, parseInt('0755', 8)).addCallback(function(fd) {
-    return posix.write(fd, js);
+  fs.open(parser_path, process.O_CREAT | process.O_WRONLY | process.O_TRUNC, parseInt('0755', 8)).addCallback(function(fd) {
+    return fs.write(fd, js);
   });
 })();
\ No newline at end of file
diff --git a/src/command_line.coffee b/src/command_line.coffee
index 43d4b107..a0c7f022 100644
--- a/src/command_line.coffee
+++ b/src/command_line.coffee
@@ -1,4 +1,4 @@
-posix:    require 'posix'
+fs:       require 'fs'
 path:     require 'path'
 coffee:   require 'coffee-script'
 optparse: require('optparse')
@@ -67,7 +67,7 @@ compile: (script, source) ->
 compile_scripts: ->
   return unless source: sources.shift()
   opts: options
-  posix.cat(source).addCallback (code) ->
+  fs.cat(source).addCallback (code) ->
     if      opts.tokens   then puts coffee.print_tokens coffee.tokenize code
     else if opts.tree     then puts coffee.tree(code).toString()
     else
@@ -83,8 +83,8 @@ write_js: (source, js) ->
   filename: path.basename(source, path.extname(source)) + '.js'
   dir:      options.output or path.dirname(source)
   js_path:  path.join dir, filename
-  posix.open(js_path, process.O_CREAT | process.O_WRONLY | process.O_TRUNC, parseInt('0755', 8)).addCallback (fd) ->
-    posix.write(fd, js)
+  fs.open(js_path, process.O_CREAT | process.O_WRONLY | process.O_TRUNC, parseInt('0755', 8)).addCallback (fd) ->
+    fs.write(fd, js)
 
 # Pipe compiled JS through JSLint (requires a working 'jsl' command).
 lint: (js) ->
diff --git a/src/grammar.coffee b/src/grammar.coffee
index d467cb5c..fe7cfb5f 100644
--- a/src/grammar.coffee
+++ b/src/grammar.coffee
@@ -455,7 +455,7 @@ js: parser.generate()
 
 # Save the parser to a file.
 # puts parser.generate()
-posix: require 'posix'
+fs: require 'fs'
 parser_path: 'lib/coffee_script/parser.js'
-posix.open(parser_path, process.O_CREAT | process.O_WRONLY | process.O_TRUNC, parseInt('0755', 8)).addCallback (fd) ->
-  posix.write(fd, js)
+fs.open(parser_path, process.O_CREAT | process.O_WRONLY | process.O_TRUNC, parseInt('0755', 8)).addCallback (fd) ->
+  fs.write(fd, js)