For example, to override the database atnt/3's root folder, you could use the cli option --database:

./bin/beat exp run <example> --database='atnt/3=../atnt_db'

This could be expanded to experiment parameters (overriding values defined in experiment JSON files) by giving JSON objects. The following format could be used:

./bin/beat exp run <example> --override='"globals":{"user/pca/1":{"number-of-components": 20}}'