diff --git a/src/applications/diffusion/controller/DiffusionServeController.php b/src/applications/diffusion/controller/DiffusionServeController.php
--- a/src/applications/diffusion/controller/DiffusionServeController.php
+++ b/src/applications/diffusion/controller/DiffusionServeController.php
@@ -769,7 +769,7 @@
     }
 
     $command = csprintf(
-      '%s serve -R %s --stdio',
+      '%s -R %s serve --stdio',
       $bin,
       $repository->getLocalPath());
     $command = PhabricatorDaemon::sudoCommandAsDaemonUser($command);