...

A QuotasCommand would be constructed with an associated script for managing quotas via command line.

FlagsCommon flags:
--bootstrap-server (required). : The standard bootstrap server.
--command-config: Property file for the Admin client.

Operations (mutually exclusive):
--list: Lists the entities that match the given specification, and prints out their configuration values.
--describe: Describes the effective quota values for an entity.
--alter: Alters the configuration for the given specification.

Entity specification flags (common to all):
---describe names: Comma-separated list of type=name pairs, e.g. --names=user=some-user,client-id=some-client-id
--defaults: Comma-separated list of entity types with the default name, e.g. defaults=user,client-id (Note a separate flag is necessary since names are opaque.)

Exclusive to --list:
--match: Comma-separated prefix=name pairs, e.g. --match=prefix=user

Exclusive to --describe:
--include-overrides: Whether to include overridden config entries.

Exclusive to --alter:
--add: Adds or updates a configuration entry to the given value. The unit must be specified.
--delete: Removes a configuration entry.
--validate-only: If set, validates the alteration but doesn't perform it.

TODO: Specify output.

Proposed Changes

In addition to the API changes above, the following write protocol would be implemented:

...