diff --git a/lisp/progmodes/etags-regen.el b/lisp/progmodes/etags-regen.el
index 14791c944ef..7994303284b 100644
--- a/lisp/progmodes/etags-regen.el
+++ b/lisp/progmodes/etags-regen.el
@@ -381,7 +381,7 @@ File extensions to generate the tags for."
     ;; Like 10ms vs 20ms here.  But `shell-command' makes it easy to
     ;; direct stderr to a separate buffer.
     (shell-command
-     (format "%s %s %s -o -"
+     (format "%s %s -o - %s"
              etags-regen-program (mapconcat #'identity options " ")
              (mapconcat #'identity file-names " "))
      t etags-regen--errors-buffer-name))