(DOCSP-10354): Landing page (#2)

* (DOCSP-10354): Landing page

* Updates per Max's feedback

* Updates per review

Author: jeff-allen-mongo

snooty.toml

@@ -6,7 +6,7 @@ intersphinx = ["https://docs.mongodb.com/manual/objects.inv"]
 toc_landing_pages = []
 
 [constants]
-mdb-shell = "MongoDB Shell"
+mdb-shell = "The MongoDB Shell"
 
 [substitutions]
 
@@ -70,6 +70,7 @@ kmip = ":abbr:`KMIP (Key Management Interoperability)`"
 kms = ":abbr:`KMS (Key Management Service)`"
 ldaps = ":abbr:`LDAPS (Secure Lightweight Directory Access Protocol)`"
 ldap = ":abbr:`LDAP (Lightweight Directory Access Protocol)`"
+mdb-shell= "MongoDB Shell"
 mms-full = "MongoDB Cloud Manager"
 mms = "Cloud Manager"
 mongo = ":binary:`~bin.mongo`"

source/includes/admonitions/fact-mdb-shell-beta.rst

@@ -0,0 +1,6 @@
+.. admonition:: Beta
+   :class: note
+
+   |mdb-shell| is currently available as a **Beta** release. The
+   product, its features, and the corresponding documentation may
+   change during the Beta stage.

source/index.txt

@@ -1,3 +1,5 @@
+.. _mdb-shell-overview:
+
 =============
 MongoDB Shell
 =============
@@ -10,6 +12,104 @@ MongoDB Shell
    :depth: 1
    :class: singlecol
 
+.. include:: /includes/admonitions/fact-mdb-shell-beta.rst
+
+The |mdb-shell| is a fully functional JavaScript environment for
+interacting with MongoDB deployments. You can use the |mdb-shell| to
+test queries and operations directly with your database.
+
+The |mdb-shell| is available as a standalone package in the MongoDB
+download center.
+
+Download and Install the |mdb-shell|
+------------------------------------
+
+.. tabs-platforms::
+
+   .. tab::
+      :tabid: windows
+
+      Hello, I am Windows content.
+
+   .. tab::
+      :tabid: macOS
+
+      Hello, I am macOS content.
+
+   .. tab::
+      :tabid: linux
+      
+      Hello, I am Linux (rpm / deb) content.
+
+Multi-Line Operations in the |mdb-shell|
+----------------------------------------
+
+Run the ``.editor`` command within the |mdb-shell| to open the editor
+and manage comprehensive multiline functions:
+
+.. example::
+
+   Run the following command within the |mdb-shell|:
+
+   .. code-block:: javascript
+
+      .editor
+
+   The |mdb-shell| enters editor mode:
+
+   .. code-block:: javascript
+      :copyable: false
+
+      // Entering editor mode (^D to finish, ^C to cancel)
+      const { Writable } = require('stream');
+
+        const myWritable = new Writable({
+          write(chunk, encoding, callback) {
+            // ...
+          },
+          writev(chunks, callback) {
+            // ...
+          }
+        });
+
+- Press ``Cmd/Ctrl`` + ``d`` to finish and run your function.
+
+- Press ``Cmd/Ctrl`` + ``c`` to cancel and exit without running your
+  function.
+
+When you close the editor, the |mdb-shell| does not save any functions
+you had entered into the editor.
+
+.. note::
+
+   Currently, ``editor()`` is the only way to paste multiline commands
+   into the |mdb-shell|.
+
+
+The |mdb-shell| versus the Legacy ``mongo`` Shell
+-------------------------------------------------
+
+The |mdb-shell| offers numerous advantages over the legacy
+:binary:`mongo <mongo>` shell, such as:
+
+- Improved syntax highlighting.
+
+- Improved command history.
+
+- Improved logging.
+
+During the beta stage, the |mdb-shell| supports a subset of the legacy
+:binary:`mongo <mongo>` shell commands. Extending the |mdb-shell| |api|
+coverage is an ongoing effort.
+
+The commands that the |mdb-shell| supports use the same syntax as the
+corresponding commands in the legacy :binary:`mongo <mongo>` shell.
+
+Learn More
+----------
+
+.. This will effectively be a ToC linking out to other parts of the docs
+
 .. class:: hidden
 
    .. toctree::