diff --git a/.dir-locals.el b/.dir-locals.el
index 21e495a4626bc6641f199852bf8efcd9602493d4..6dbdc9aed4057c56b27f040410c2f5226685bae6 100644
--- a/.dir-locals.el
+++ b/.dir-locals.el
@@ -1,6 +1,6 @@
-((nil .
-      ((c-file-style . "gnu")
-       (indent-tabs-mode . nil)
-       (fill-column . 79)))
- (c-mode . (c-basic-offset 2))
- (makefile-mode . ((indent-tabs-mode . t))))
+((nil . ((indent-tabs-mode . nil)
+         (fill-column . 79)))
+ (c-mode . ((c-file-style . "gnu")))
+ (c++-mode . ((c-file-style . "gnu")))
+ (makefile-mode . ((indent-tabs-mode . t)))
+ (octave-mode . ((octave-block-offset . 4))))