johnkerl/miller ? reverse-engineered prompt

Build me a fast command line tool for cleaning and reshaping table like data from the terminal.

I want it to work with CSV, TSV, JSON, JSON Lines, and simple column based text, so I can use field names instead of counting positions. It should let me filter rows, add new columns from existing values, drop columns, sort data, group and summarize it, and convert between formats. It should feel like the Unix tools people already know, so it works well in pipes and on huge files without loading everything into memory.

Please make it friendly for logs and messy data too, including cases where different rows don’t all have the same fields. If possible, include a few useful examples in the help text and make the output easy to read in the terminal. If you need to look up current docs online while building it, go ahead.