diff -r 7219cd440d4c Doc/library/os.rst
--- a/Doc/library/os.rst	Sat Oct 20 16:27:51 2012 +0300
+++ b/Doc/library/os.rst	Sat Oct 20 16:23:05 2012 -0400
@@ -1720,18 +1720,21 @@
 
 .. function:: rename(src, dst, *, src_dir_fd=None, dst_dir_fd=None)
 
-   Rename the file or directory *src* to *dst*.  If *dst* is a directory,
-   :exc:`OSError` will be raised.  On Unix, if *dst* exists and is a file, it will
-   be replaced silently if the user has permission.  The operation may fail on some
-   Unix flavors if *src* and *dst* are on different filesystems.  If successful,
-   the renaming will be an atomic operation (this is a POSIX requirement).  On
-   Windows, if *dst* already exists, :exc:`OSError` will be raised even if it is a
-   file.
+   Rename the file or directory *src* to *dst*.  If *dst* is a directory that
+   is not empty, :exc:`OSError` will be raised.  On Unix, if *dst* exists and
+   is a file, it will be replaced silently if the user has permission and src
+   is a file.  On Unix, if *src* is a directory and *dst* is a file
+   :exc:`NotADirectoryError` will be raised. The operation may fail on some
+   Unix flavors if *src* and *dst* are on different filesystems.  If
+   successful, the renaming will be an atomic operation (this is a POSIX
+   requirement).  On Windows, if *dst* already exists, :exc:`OSError` will be
+   raised even if it is a file.
 
    This function can support specifying *src_dir_fd* and/or *dst_dir_fd* to
    supply :ref:`paths relative to directory descriptors <dir_fd>`.
 
-   If you want cross-platform overwriting of the destination, use :func:`replace`.
+   If you want cross-platform overwriting of the destination, use
+   :func:`replace`.
 
    Availability: Unix, Windows.