There shall be one commandline tool per client API, which provides full access to all of its features using the common 'sub-command' pattern.

The purpose of these is to allow command-line testing of the APIs to see if they truly work as advertised.

It will come built-in with a publicly available client secret, but will try to read a secret file to allow users to bypass possible quota limit hits.

They should allow resumable uploads, which requires some degree of (simple) persistence. It could, for example, drop a json file with the information it obtained so far.