Merge pull request #32 from sarcastron/bugfix/undefined-index-cache

Check for non-empty value instead of intrinsic truthy value.

src/Command/LintCommand.php

@@ -154,7 +154,7 @@ protected function execute(InputInterface $input, OutputInterface $output)
         $linter = new Linter($options['path'], $options['exclude'], $options['extensions']);
         $linter->setProcessLimit($options['jobs']);
 
-        if ($options['cache']) {
+        if (!empty($options['cache'])) {
             Cache::setFilename($options['cache']);
         }