diff --git a/.dir-locals.el b/.dir-locals.el
new file mode 100644
index 000000000..19533e91a
--- /dev/null
+++ b/.dir-locals.el
@@ -0,0 +1,3 @@
+;; This tells Emacs to automatically run whitespace-cleanup when
+;; editing any file in the S3QL source tree.
+((nil . ((eval . (add-hook 'before-save-hook 'whitespace-cleanup nil t)))))
diff --git a/rst/backends.rst b/rst/backends.rst
index af1f7e645..53ad9965c 100644
--- a/rst/backends.rst
+++ b/rst/backends.rst
@@ -19,7 +19,7 @@ options are documented with the respective backends below.
 
 All storage backends respect the :envvar:`!http_proxy` (for plain HTTP
 connections) and :envvar:`!https_proxy` (for SSL connections)
-environment variables. 
+environment variables.
 
 
 Google Storage
diff --git a/src/s3ql/adm.py b/src/s3ql/adm.py
index 27a5dd84a..bc9107aaf 100644
--- a/src/s3ql/adm.py
+++ b/src/s3ql/adm.py
@@ -92,7 +92,7 @@ def main(args=None):
 
     if options.action == 'upgrade':
         return upgrade(options)
-    
+
     with get_backend(options) as backend:
         if options.action == 'passphrase':
             return change_passphrase(backend)
diff --git a/src/s3ql/common.py b/src/s3ql/common.py
index 61af9373d..f426e3a27 100644
--- a/src/s3ql/common.py
+++ b/src/s3ql/common.py
@@ -538,7 +538,7 @@ def split_by_n(seq, n):
     while seq:
         yield seq[:n]
         seq = seq[n:]
-        
+
 def handle_on_return(fn):
     '''Provide fresh ExitStack instance in `on_return` argument'''
     @functools.wraps(fn)