diff --git a/lib/cli.js b/lib/cli.js
index <HASH>..<HASH> 100644
--- a/lib/cli.js
+++ b/lib/cli.js
@@ -102,10 +102,11 @@ function processFile(filename, config) {
     eslint.reset();
 
     var filePath = path.resolve(filename),
+        existsSync = fs.existsSync || path.existsSync,
         text,
         messages;
 
-    if (fs.existsSync(filePath)) {
+    if (existsSync(filePath)) {
         text = fs.readFileSync(path.resolve(filename), "utf8");
         messages = eslint.verify(text, config);
     } else {
Fixes issue with fs.existsSync on NodeJS <I>

Fixes an issue where`lib/cli.js` was using `fs.existsSync`, which prior to NodeJS <I> was `path.existsSync`. So, on NodeJS <I>, the CLI would throw an error.