diff --git a/src/Symfony/Component/Console/Command/Command.php b/src/Symfony/Component/Console/Command/Command.php
index bcb86cdfbe..ab03120653 100644
--- a/src/Symfony/Component/Console/Command/Command.php
+++ b/src/Symfony/Component/Console/Command/Command.php
@@ -29,6 +29,7 @@ use Symfony\Component\Console\Output\OutputInterface;
  */
 class Command
 {
+    // see https://tldp.org/LDP/abs/html/exitcodes.html
     public const SUCCESS = 0;
     public const FAILURE = 1;