Yes, flags vs. config files in Unix are a classic example of dependency injection vs. side effects, but at the process level rather than the programming language level.

At Google pretty much all server configuration is done with flags. Binaries can and do have thousands of flags. And I view that as a much better solution than a config file that is searched for.

The idea is that modular units like processes and functions don't "search for configuration", they just accept parameters, and led the higher level application configure them. Then the code becomes very straightforward to read and debug.