diff --git a/rubberin b/rubberin
index 9ec3f4b..e093a28 100755
--- a/rubberin
+++ b/rubberin
@@ -143,12 +143,9 @@ if ARGV.empty?
   exit 1
 else
   infile = Pathname.new(ARGV.shift)
-  def infile.base
-    basename(extname)
-  end
 
   def infile.with_extname(ext)
-    file = base
+    file = dirname + basename(extname)
     file.extname = ".#{ext}"
     file
   end