docker pull: always show me "Layer already being pulled by another client. Waiting."

After the command:

$docker pull openeai/openeai-examples:2015a,  seeing that issue, use Control-C to stop it, and then

$ docker-machine stop default

after it is done, do the pull again.

reference is here

How to find the process of the Docker vm

$ps -ef|grep VBox

Dock Tool Terminal not working

Remove your version of Docker and install the version 1.8.2 (NOT 1.8.2c).  Here is the install link for the mac version

https://github.com/docker/toolbox/releases/download/v1.8.2/DockerToolbox-1.8.2.pkg