Just go for `--json-output=filename` rather than playing games.

Why filename? It doesn't need to know how to write files. That's what Greater than is for. Do --output=json

It seemed that the author wants to write JSON in addition to regular output.

	▲	8n4vidtmkvmk an hour ago \| parent [-]
		Oh.. ya ok I guess you need to specify where to direct each output then. Kind of a weird use case. If it's not slow to process, you can usually just call the program twice.