head

Extracts the first N rows from a data file. Useful for quick data inspection.

Without --output, rows are written as JSONL to stdout even when the input is CSV. The output format follows the --output extension when writing a file.

# Extract first 10 rows (default) as JSONL on stdout
undatum head data.csv

# Extract first 20 rows
undatum head data.jsonl --n 20

# Save to file (not a positional path)
undatum head data.csv --n 5 --output output.csv

# Named Excel sheet
undatum head workbook.xlsx --table Sheet2 --n 5

# Nested JSONL: unfold dict fields onto dotted paths
undatum head nested.jsonl --flatten-nested --n 5

Key options: --n (default 10), --output, --table / --sheet, --flatten-nested, --trust. See shared options.