Step 1. Launch a docker container
```shell
    $ docker run -it ubuntu /bin/bash
```
Step 2. Run the following INSIDE the container
```shell
    $ export LOCATION="SFS in Denver"
    $ sleep 1000
```
Step 3. Run outside the container in another window at the same time
```shell
    $ cat /proc/`pgrep sleep`/environ | tr '\0' '\n'
```
The cat command provides you with a list of environment variables.  
So if you are following [The Twelve-Factor App](https://12factor.net) and passing all your configuration in using
environment variables the only secrets can be exposed to the host container.