Break the modules docs into separate files.

rst/modules/shell.rst

@@ -0,0 +1,31 @@
+.. _shell:
+
+shell
+`````
+
+The shell module takes the command name followed by a list of
+arguments, space delimited.  It is almost exactly like the command module
+but runs the command through the user's configured shell on the remote node.
+
++--------------------+----------+---------+----------------------------------------------------------------------------+
+| parameter          | required | default | comments                                                                   |
++====================+==========+=========+============================================================================+
+| (free form)        | N/A      | N/A     | the command module takes a free form command to run                        |
++--------------------+----------+---------+----------------------------------------------------------------------------+
+| creates            | no       |         | a filename, when it already exists, this step will NOT be run              |
++--------------------+----------+---------+----------------------------------------------------------------------------+
+| chdir              | no       |         | cd into this directory before running the command (0.6 and later)          |
++--------------------+----------+---------+----------------------------------------------------------------------------+
+
+The given command will be executed on all selected nodes.
+
+.. note::
+   If you want to execute a command securely and predicably, it may be
+   better to use the 'command' module instead.  Best practices when
+   writing playbooks will follow the trend of using 'command' unless
+   'shell' is explicitly required.  When running ad-hoc commands, use
+   your best judgement.
+
+Example action from a playbook::
+
+    shell somescript.sh >> somelog.txt