diff --git a/lib/command_parse.y b/lib/command_parse.y
index 6348643b8b..e381507cc3 100644
--- a/lib/command_parse.y
+++ b/lib/command_parse.y
@@ -198,7 +198,7 @@ sentence_root: WORD
 ;
 
 cmd_token_seq:
-  %empty
+  /* empty */
 | cmd_token_seq cmd_token
 ;