#6374: add a bit of explanation about shell=True on Windows.
diff --git a/Doc/library/subprocess.rst b/Doc/library/subprocess.rst
index e5a86e6..b903c8c 100644
--- a/Doc/library/subprocess.rst
+++ b/Doc/library/subprocess.rst
@@ -73,7 +73,11 @@
needed: Usually, the program to execute is defined by the *args* argument. If
``shell=True``, the *executable* argument specifies which shell to use. On Unix,
the default shell is :file:`/bin/sh`. On Windows, the default shell is
- specified by the :envvar:`COMSPEC` environment variable.
+ specified by the :envvar:`COMSPEC` environment variable. The only reason you
+ would need to specify ``shell=True`` on Windows is where the command you
+ wish to execute is actually built in to the shell, eg ``dir``, ``copy``.
+ You don't need ``shell=True`` to run a batch file, nor to run a console-based
+ executable.
*stdin*, *stdout* and *stderr* specify the executed programs' standard input,
standard output and standard error file handles, respectively. Valid values