Created file class with File::extension method, added File to aliases under application

application/config/application.php

@@ -103,6 +103,7 @@ return array(
 		'DB' => 'System\\DB',
 		'Download' => 'System\\Download',
 		'Eloquent' => 'System\\DB\\Eloquent',
+		'File' => 'System\\File',
 		'Form' => 'System\\Form',
 		'Hash' => 'System\\Hash',
 		'HTML' => 'System\\HTML',

system/file.php

+<?php namespace System;
+
+class File {
+	
+	/**
+	 * Get a file's extension. 
+	 * 
+	 * @param  string $path
+	 * @return string
+	 */
+	public static function extension($path)
+	{
+		return pathinfo($path, PATHINFO_EXTENSION);
+	}
+
+}
\ No newline at end of file