tail

Extracts the last N rows from a data file. Uses efficient buffering for large files.

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 last 10 rows (default) as JSONL on stdout
undatum tail data.csv

# Extract last 50 rows
undatum tail data.jsonl --n 50

# Save to file (not a positional path)
undatum tail data.csv --n 20 --output output.csv

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

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

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