Not clear in documentation config file usage

[garry-t]

In docs I we see Configuration File The configuration file controls the behavior of the exporter. It can be set using the --config.file command line flag and defaults to postgres_exporter.yml.

But what if I dont want to use, will it fail? I plan upgrade from 0.9.0 version and want to use exact same approach and don't want to use this fancy approach.

Please elaborate for me thanks.