diff --git a/src/Symfony/Bundle/FrameworkBundle/Command/YamlLintCommand.php b/src/Symfony/Bundle/FrameworkBundle/Command/YamlLintCommand.php
index 54c446de33013..b7f46d1e9d163 100644
--- a/src/Symfony/Bundle/FrameworkBundle/Command/YamlLintCommand.php
+++ b/src/Symfony/Bundle/FrameworkBundle/Command/YamlLintCommand.php
@@ -11,6 +11,10 @@
 
 namespace Symfony\Bundle\FrameworkBundle\Command;
 
+if (!defined('JSON_PRETTY_PRINT')) {
+    define('JSON_PRETTY_PRINT', 128);
+}
+
 use Symfony\Component\Console\Command\Command;
 use Symfony\Component\Console\Input\InputInterface;
 use Symfony\Component\Console\Input\InputOption;
@@ -151,7 +155,7 @@ private function displayJson(OutputInterface $output, $filesInfo)
             }
         });
 
-        $output->writeln(json_encode($filesInfo));
+        $output->writeln(json_encode($filesInfo, JSON_PRETTY_PRINT));
 
         return min($errors, 1);
     }