Add docs for shell

Author: markpollack

spring-cloud-dataflow-docs/src/main/asciidoc/configuration.adoc

@@ -3,7 +3,38 @@
 [partintro]
 --
 In this section you will learn how to configure Spring Cloud Data Flow server's features such as the relational database to use and security.
+You will also learn how to configure Spring Cloud Data Flow shell's features.
 --
+
+[[shell-options]]
+== Shell Options
+The shell takes the following command line options
+[source,bash]
+----
+unix:>java -jar spring-cloud-dataflow-shell-1.2.1.RELEASE.jar --help
+Data Flow Options:
+  --dataflow.uri=<uri>                              Address of the Data Flow Server [default: http://localhost:9393].
+  --dataflow.username=<USER>                        Username of the Data Flow Server [no default].
+  --dataflow.password=<PASSWORD>                    Password of the Data Flow Server [no default].
+  --dataflow.credentials-provider-command=<COMMAND> Executes an external command which must return an OAuth Access Token [no default].
+  --dataflow.skip-ssl-validation=<true|false>       Accept any SSL certificate (even self-signed) [default: no].
+  --spring.shell.historySize=<SIZE>                 Default size of the shell log file [default: 3000].
+  --spring.shell.commandFile=<FILE>                 Data Flow Shell executes commands read from the file(s) and then exits.
+  --help                                            This message.
+----
+
+The `spring.shell.commandFile` option is of note, as it can be used to point to an existing file which contains
+all the shell commands to deploy one or many related streams and tasks.  This is useful when creating some scripts to
+help automate the deployment.
+
+There is also a shell command
+[source,bash]
+----
+dataflow:>script --file <YOUR_AWESOME_SCRIPT>
+----
+This is useful to help modularize a complex script into multiple indepenent files.
+
+
 [[enable-disable-specific-features]]
 == Feature Toggles