make all image ID and container ID API responses use the Long ID (Closes #2098)

Upstream-commit: b3974abe4f01d408850e245c9b52c77f3571e0b2
Component: engine

components/engine/docs/sources/terms/container.rst

@@ -38,3 +38,10 @@ was when the container was stopped.
 You can promote a container to an :ref:`image_def` with ``docker
 commit``. Once a container is an image, you can use it as a parent for
 new containers.
+
+Container IDs
+.............
+All containers are identified by a 64 hexadecimal digit string (internally a 256bit 
+value). To simplify their use, a short ID of the first 12 characters can be used 
+on the commandline. There is a small possibility of short id collisions, so the 
+docker server will always return the long ID.

components/engine/docs/sources/terms/image.rst

@@ -36,3 +36,11 @@ Base Image
 ..........
 
 An image that has no parent is a **base image**.
+
+Image IDs
+.........
+All images are identified by a 64 hexadecimal digit string (internally a 256bit 
+value). To simplify their use, a short ID of the first 12 characters can be used 
+on the command line. There is a small possibility of short id collisions, so the 
+docker server will always return the long ID.
+

components/engine/docs/sources/use/basics.rst

@@ -22,22 +22,37 @@ specify the path to it and manually start it.
     # Run docker in daemon mode
     sudo <path to>/docker -d &
 
-
-Running an interactive shell
-----------------------------
+Download a pre-built image
+--------------------------
 
 .. code-block:: bash
 
   # Download an ubuntu image
   sudo docker pull ubuntu
 
+This will find the ``ubuntu`` image by name in the :ref:`Central Index 
+<searching_central_index>` and download it from the top-level Central 
+Repository to a local image cache.
+
+.. NOTE:: When the image has successfully downloaded, you will see a 12 
+character hash ``539c0211cd76: Download complete`` which is the short 
+form of the image ID. These short image IDs are the first 12 characters 
+of the full image ID - which can be found using ``docker inspect`` or 
+``docker images -notrunc=true``
+
+.. _dockergroup:
+
+Running an interactive shell
+----------------------------
+
+.. code-block:: bash
+
   # Run an interactive shell in the ubuntu image,
   # allocate a tty, attach stdin and stdout
   # To detach the tty without exiting the shell,
   # use the escape sequence Ctrl-p + Ctrl-q
   sudo docker run -i -t ubuntu /bin/bash
 
-.. _dockergroup:
 
 Why ``sudo``?
 -------------