diff --git a/sample/dir.rb b/sample/dir.rb
index 44733c2cf4..0c55078973 100644
--- a/sample/dir.rb
+++ b/sample/dir.rb
@@ -3,7 +3,7 @@
 dirp = Dir.open(".")
 for f in dirp
   case f
-  when /\A\./, /~\z/, /\.o/
+  when /\A\./, /~\z/, /\.o\z/
     # do not print
   else
     print f, "\n"