xsv

xsv is a command-line tool for indexing, slicing, analyzing, splitting, and joining CSV files, written in Rust by Andrew Gallant (BurntSushi, also the creator of ripgrep). With over 10,500 stars as of 2026, xsv is the fastest CSV toolkit available, capable of processing multi-gigabyte CSV files in seconds thanks to Rust's zero-overhead abstractions and memory-mapped file I/O. Key commands include: xsv index (creating an index file for fast random access to rows by position or field value), xsv slice (extracting rows by index range, start/end, or specific indices), xsv search (finding rows matching a regex pattern in a specific column), xsv select (choosing specific columns from the CSV), xsv sort (sorting rows by column value with natural sort for numbers and dates), xsv frequency (computing frequency tables for column values, showing the most common values), xsv stats (computing statistics for each column including min, max, mean, stddev, median, mode, null count, and type inference), xsv table (formatting CSV data as aligned tables for readability), xsv join (joining two CSV files on a common column, supporting inner, outer, left, and cross joins), xsv cat (concatenating CSV files row-wise or column-wise), xsv fmt (converting between CSV and TSV formats), xsv flatten (transposing rows to columns for single-record display), xsv fixlengths (padding or truncating records to a uniform column count), and xsv count (counting rows instantly using the index).