diff --git a/Doc/library/_thread.rst b/Doc/library/_thread.rst
index 95214d6..cb62407 100644
--- a/Doc/library/_thread.rst
+++ b/Doc/library/_thread.rst
@@ -147,7 +147,7 @@
   module is available, interrupts always go to the main thread.)
 
 * Calling :func:`sys.exit` or raising the :exc:`SystemExit` exception is
-  equivalent to calling :func:`exit`.
+  equivalent to calling :func:`_thread.exit`.
 
 * Not all built-in functions that may block waiting for I/O allow other threads
   to run.  (The most popular ones (:func:`time.sleep`, :meth:`file.read`,
diff --git a/Doc/library/codecs.rst b/Doc/library/codecs.rst
index 82d63b0..8116694 100644
--- a/Doc/library/codecs.rst
+++ b/Doc/library/codecs.rst
@@ -891,7 +891,8 @@
 name, together with a few common aliases, and the languages for which the
 encoding is likely used. Neither the list of aliases nor the list of languages
 is meant to be exhaustive. Notice that spelling alternatives that only differ in
-case or use a hyphen instead of an underscore are also valid aliases.
+case or use a hyphen instead of an underscore are also valid aliases; therefore,
+e.g. ``'utf-8'`` is a valid alias for the ``'utf_8'`` codec.
 
 Many of the character sets support the same languages. They vary in individual
 characters (e.g. whether the EURO SIGN is supported or not), and in the
diff --git a/Doc/library/ctypes.rst b/Doc/library/ctypes.rst
index ded0df8..ad5adee 100644
--- a/Doc/library/ctypes.rst
+++ b/Doc/library/ctypes.rst
@@ -1592,7 +1592,7 @@
    The returned function prototype creates functions that use the standard C
    calling convention.  The function will release the GIL during the call.  If
    *use_errno* is set to True, the ctypes private copy of the system
-   :data:`errno` variable is exchanged with the real :data:`errno` value bafore
+   :data:`errno` variable is exchanged with the real :data:`errno` value before
    and after the call; *use_last_error* does the same for the Windows error
    code.
 
diff --git a/Doc/library/math.rst b/Doc/library/math.rst
index 488230a..566603d 100644
--- a/Doc/library/math.rst
+++ b/Doc/library/math.rst
@@ -150,8 +150,10 @@
 
 .. function:: log(x[, base])
 
-   Return the logarithm of *x* to the given *base*. If the *base* is not specified,
-   return the natural logarithm of *x* (that is, the logarithm to base *e*).
+   With one argument, return the natural logarithm of *x* (to base *e*).
+
+   With two arguments, return the logarithm of *x* to the given *base*,
+   calculated as ``log(x)/log(base)``.
 
 
 .. function:: log1p(x)
@@ -162,7 +164,8 @@
 
 .. function:: log10(x)
 
-   Return the base-10 logarithm of *x*.
+   Return the base-10 logarithm of *x*.  This is usually more accurate
+   than ``log(x, 10)``.
 
 
 .. function:: pow(x, y)
diff --git a/Doc/library/optparse.rst b/Doc/library/optparse.rst
index 6320fa7..a62ad24 100644
--- a/Doc/library/optparse.rst
+++ b/Doc/library/optparse.rst
@@ -1166,19 +1166,20 @@
    the list of arguments to process (default: ``sys.argv[1:]``)
 
 ``values``
-   object to store option arguments in (default: a new instance of optparse.Values)
+   object to store option arguments in (default: a new instance of
+   :class:`optparse.Values`)
 
 and the return values are
 
 ``options``
-   the same object that was passed in as ``options``, or the optparse.Values
+   the same object that was passed in as ``values``, or the optparse.Values
    instance created by :mod:`optparse`
 
 ``args``
    the leftover positional arguments after all options have been processed
 
 The most common usage is to supply neither keyword argument.  If you supply
-``options``, it will be modified with repeated ``setattr()`` calls (roughly one
+``values``, it will be modified with repeated ``setattr()`` calls (roughly one
 for every option argument stored to an option destination) and returned by
 :meth:`parse_args`.
 
diff --git a/Doc/library/os.rst b/Doc/library/os.rst
index 2548b70..9bed1ce 100644
--- a/Doc/library/os.rst
+++ b/Doc/library/os.rst
@@ -947,12 +947,12 @@
 
 .. function:: remove(path)
 
-   Remove the file *path*.  If *path* is a directory, :exc:`OSError` is raised; see
-   :func:`rmdir` below to remove a directory.  This is identical to the
-   :func:`unlink` function documented below.  On Windows, attempting to remove a
-   file that is in use causes an exception to be raised; on Unix, the directory
-   entry is removed but the storage allocated to the file is not made available
-   until the original file is no longer in use. Availability: Unix,
+   Remove (delete) the file *path*.  If *path* is a directory, :exc:`OSError` is
+   raised; see :func:`rmdir` below to remove a directory.  This is identical to
+   the :func:`unlink` function documented below.  On Windows, attempting to
+   remove a file that is in use causes an exception to be raised; on Unix, the
+   directory entry is removed but the storage allocated to the file is not made
+   available until the original file is no longer in use. Availability: Unix,
    Windows.
 
 
@@ -997,7 +997,10 @@
 
 .. function:: rmdir(path)
 
-   Remove the directory *path*. Availability: Unix, Windows.
+   Remove (delete) the directory *path*.  Only works when the directory is
+   empty, otherwise, :exc:`OSError` is raised.  In order to remove whole
+   directory trees, :func:`shutil.rmtree` can be used.  Availability: Unix,
+   Windows.
 
 
 .. function:: stat(path)
@@ -1099,9 +1102,9 @@
 
 .. function:: unlink(path)
 
-   Remove the file *path*.  This is the same function as :func:`remove`; the
-   :func:`unlink` name is its traditional Unix name. Availability: Unix,
-   Windows.
+   Remove (delete) the file *path*.  This is the same function as
+   :func:`remove`; the :func:`unlink` name is its traditional Unix
+   name. Availability: Unix, Windows.
 
 
 .. function:: utime(path, times)
diff --git a/Doc/library/signal.rst b/Doc/library/signal.rst
index 2db17c5..7319ac9 100644
--- a/Doc/library/signal.rst
+++ b/Doc/library/signal.rst
@@ -205,9 +205,9 @@
    exception to be raised.
 
    The *handler* is called with two arguments: the signal number and the current
-   stack frame (``None`` or a frame object; for a description of frame objects, see
-   the reference manual section on the standard type hierarchy or see the attribute
-   descriptions in the :mod:`inspect` module).
+   stack frame (``None`` or a frame object; for a description of frame objects,
+   see the :ref:`description in the type hierarchy <frame-objects>` or see the
+   attribute descriptions in the :mod:`inspect` module).
 
 
 .. _signal-example:
diff --git a/Doc/library/stdtypes.rst b/Doc/library/stdtypes.rst
index 14ad15e..f739f46 100644
--- a/Doc/library/stdtypes.rst
+++ b/Doc/library/stdtypes.rst
@@ -1724,12 +1724,12 @@
    .. method:: update(other, ...)
                set |= other | ...
 
-      Update the set, adding elements from *other*.
+      Update the set, adding elements from all others.
 
    .. method:: intersection_update(other, ...)
                set &= other & ...
 
-      Update the set, keeping only elements found in it and *other*.
+      Update the set, keeping only elements found in it and all others.
 
    .. method:: difference_update(other, ...)
                set -= other | ...
@@ -2478,9 +2478,9 @@
 their implementation of the context management protocol. See the
 :mod:`contextlib` module for some examples.
 
-Python's :term:`generator`\s and the ``contextlib.contextfactory`` :term:`decorator`
+Python's :term:`generator`\s and the ``contextlib.contextmanager`` :term:`decorator`
 provide a convenient way to implement these protocols.  If a generator function is
-decorated with the ``contextlib.contextfactory`` decorator, it will return a
+decorated with the ``contextlib.contextmanager`` decorator, it will return a
 context manager implementing the necessary :meth:`__enter__` and
 :meth:`__exit__` methods, rather than the iterator produced by an undecorated
 generator function.
diff --git a/Doc/reference/datamodel.rst b/Doc/reference/datamodel.rst
index 14e0b20..ef2f382 100644
--- a/Doc/reference/datamodel.rst
+++ b/Doc/reference/datamodel.rst
@@ -864,6 +864,8 @@
       If a code object represents a function, the first item in :attr:`co_consts` is
       the documentation string of the function, or ``None`` if undefined.
 
+   .. _frame-objects:
+
    Frame objects
       .. index:: object: frame
 
diff --git a/Doc/tutorial/classes.rst b/Doc/tutorial/classes.rst
index 7ef4153..4e166d1 100644
--- a/Doc/tutorial/classes.rst
+++ b/Doc/tutorial/classes.rst
@@ -51,8 +51,8 @@
 
 .. _tut-scopes:
 
-Python Scopes and Name Spaces
-=============================
+Python Scopes and Namespaces
+============================
 
 Before introducing classes, I first have to tell you something about Python's
 scope rules.  Class definitions play some neat tricks with namespaces, and you
@@ -87,7 +87,7 @@
 :keyword:`del` statement.  For example, ``del modname.the_answer`` will remove
 the attribute :attr:`the_answer` from the object named by ``modname``.
 
-Name spaces are created at different moments and have different lifetimes.  The
+Namespaces are created at different moments and have different lifetimes.  The
 namespace containing the built-in names is created when the Python interpreter
 starts up, and is never deleted.  The global namespace for a module is created
 when the module definition is read in; normally, module namespaces also last
@@ -381,9 +381,9 @@
 attribute that is a function object, a method object is created by packing
 (pointers to) the instance object and the function object just found together in
 an abstract object: this is the method object.  When the method object is called
-with an argument list, it is unpacked again, a new argument list is constructed
-from the instance object and the original argument list, and the function object
-is called with this new argument list.
+with an argument list, a new argument list is constructed from the instance
+object and the argument list, and the function object is called with this new
+argument list.
 
 
 .. _tut-remarks:
diff --git a/Misc/ACKS b/Misc/ACKS
index e4086bd..c9dcad0 100644
--- a/Misc/ACKS
+++ b/Misc/ACKS
@@ -791,6 +791,7 @@
 Truida Wiedijk
 Felix Wiemann
 Gerry Wiener
+Frank Wierzbicki
 Bryce "Zooko" Wilcox-O'Hearn
 John Williams
 Sue Williams
diff --git a/Misc/NEWS b/Misc/NEWS
index bc7f5b0..8c13e37 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -1549,6 +1549,9 @@
 - Issue #4204: Fixed module build errors on FreeBSD 4.
 
 
+- Issue #6801 : symmetric_difference_update also accepts |.
+  Thanks to Carl Chenet. 
+
 C-API
 -----