split

Splits datasets into multiple files based on chunk size or field values.

# Split by chunk size
undatum split --chunksize 10000 data.jsonl

# Split by field value
undatum split --fields category data.jsonl
undatum split workbook.xlsx --table Sheet2 --fields city --dirname out/
undatum split nested.jsonl --fields capital_city.lat --flatten-nested --dirname out/
undatum split events.jsonl --filter '`city` == "Berlin"' --dirname out/

--filter uses the same comparison syntax as select. --dirname is the output directory; --output can set a filename prefix. Also --gzipfile / --zipfile for compressed inputs. See shared CLI options.