Merge pull request #4526 from Rovanion/master

All caps variables in normal bash should be avoided not to accidentally collide with environment variables.

docs/sources/examples/hello_world.rst

@@ -92,7 +92,7 @@ we stop it.
 
 .. code-block:: bash
 
-    CONTAINER_ID=$(sudo docker run -d ubuntu /bin/sh -c "while true; do echo hello world; sleep 1; done")
+    container_id=$(sudo docker run -d ubuntu /bin/sh -c "while true; do echo hello world; sleep 1; done")
 
 We are going to run a simple hello world daemon in a new container
 made from the ``ubuntu`` image.
@@ -104,22 +104,22 @@ made from the ``ubuntu`` image.
 - **"while true; do echo hello world; sleep 1; done"** is the mini
   script we want to run, that will just print hello world once a
   second until we stop it.
-- **$CONTAINER_ID** the output of the run command will return a
+- **$container_id** the output of the run command will return a
   container id, we can use in future commands to see what is going on
   with this process.
 
 .. code-block:: bash
 
-    sudo docker logs $CONTAINER_ID
+    sudo docker logs $container_id
 
 Check the logs make sure it is working correctly.
 
 - **"docker logs**" This will return the logs for a container
-- **$CONTAINER_ID** The Id of the container we want the logs for.
+- **$container_id** The Id of the container we want the logs for.
 
 .. code-block:: bash
 
-    sudo docker attach -sig-proxy=false $CONTAINER_ID
+    sudo docker attach -sig-proxy=false $container_id
 
 Attach to the container to see the results in real-time.
 
@@ -127,7 +127,7 @@ Attach to the container to see the results in real-time.
   process to see what is going on.
 - **"-sig-proxy=false"** Do not forward signals to the container; allows
   us to exit the attachment using Control-C without stopping the container.
-- **$CONTAINER_ID** The Id of the container we want to attach too.
+- **$container_id** The Id of the container we want to attach too.
 
 Exit from the container attachment by pressing Control-C.
 
@@ -141,12 +141,12 @@ Check the process list to make sure it is running.
 
 .. code-block:: bash
 
-    sudo docker stop $CONTAINER_ID
+    sudo docker stop $container_id
 
 Stop the container, since we don't need it anymore.
 
 - **"docker stop"** This stops a container
-- **$CONTAINER_ID** The Id of the container we want to stop.
+- **$container_id** The Id of the container we want to stop.
 
 .. code-block:: bash