Environment filename test.

Making sure that it gets the filename when actually.
Get the full file path from the environment.

We have the technology.
Add a file option to the arguments.

Add an option to show the filename for the storage.
Switch over to the correct file.

Stop using the hardcoded test file name and use the environment
filename and file path instead.
Constructing the path.

While adding a `/` between the folder and the file works on some
platforms, it won't work everywhere.

This constucts the path with the platform-specific separator for us.
Comments.
Use a cross-platform solution for home directory.

The current way of checking HOME doesn't work on Windows.
Formatting.