Remote API - When can multiline & json be used?

When can multiline & json be used within the Remote API calls?

I receive the Error when calling (e.g. create-domain) "Unknown option --multiline"

Ideally I should be able to pass the json and/or xml and/or multiline irrespective of the API call being used

I would suggest that json, xml, multiline are parameters that are excluded from $in{} and

Additionally can "sub api_error" also honour the formating passed

Also can json -> application/json xml -> text/xml perl / undef -> text/plain