uniq

Extracts all unique values from specified field(s). --fields is required.

Default stdout format is CSV. Use --format-out json (or an --output path ending in .json) for JSON.

# Single field
undatum uniq --fields category data.jsonl

# Multiple fields (unique combinations)
undatum uniq --fields status,region data.jsonl
undatum uniq --fields city --format-out json --output cities.json data.csv
undatum uniq --fields city workbook.xlsx --table Sheet2
undatum uniq --fields capital_city.lat nested.jsonl --flatten-nested

Key options: --fields (required), --filter / --filter-expr, --format-out csv|json, --output, --engine auto|duckdb|iterable. Also accepts --table, --flatten-nested, --on-error, --error-log, and --quotechar (shared options).