transpose

Swaps rows and columns, handling headers appropriately.

Write with --output. A trailing path is not a positional argument.

# Transpose CSV file
undatum transpose data.csv --output output.csv

# Transpose JSONL file
undatum transpose data.jsonl --output output.jsonl

Key options: --output. Also accepts --table, --flatten-nested, --on-error, --error-log, and --quotechar (shared options).