xsv is a command-line program designed for working with CSV files at scale. It provides fast, composable commands for indexing, slicing, analyzing, splitting and joining CSV data with a focus on performance and simplicity.

The tool excels at handling large CSV files through intelligent indexing that enables constant-time record access. Once indexed, operations like counting rows, slicing data, and gathering statistics become nearly instantaneous—even on files with millions of records.

Key capabilities include:

Data exploration: headers, stats, frequency tables, and flattened views
Data manipulation: select columns, slice rows, sort, search with regex
Data transformation: cat, split, join, partition, and format conversion
Performance optimization: index creation for blazing-fast queries on large datasets

xsv works best for data analysts, programmers, and students exploring small to medium datasets in a UNIX-like fashion. It's particularly valuable when you need to count records, manipulate CSV data, and perform quick analysis without leaving the terminal.

Note: xsv is no longer actively maintained. The project recommends using qsv or xan as modern alternatives, with xan being considered the newer successor.

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