Xz

XZ refers to a data compression format and the XZ Utils software package. It uses the LZMA2 compression algorithm to deliver high compression ratios with fast decompression, making it competitive with other widely used formats such as gzip and bzip2, especially for large files. The XZ format supports streaming, a range of compression levels, and configurable dictionary sizes. It also provides an integrity check mechanism, with options such as CRC32, CRC64, or SHA-256 to verify data integrity. A single file compressed with XZ typically has the .xz extension, and XZ is also commonly used to compress tar archives (tar.xz).

The XZ Utils project includes command-line tools for compressing and decompressing data. The primary tool is xz, which can perform compression and decompression, with options to preserve the original file (-k), write output to stdout (-c), and control multi-threading (-T). Examples: to compress a file, run xz file.txt; to decompress, run xz -d file.txt.xz; to keep the original file, use xz -k file.txt.xz. For multi-file archives, a tar archive can be compressed with XZ, for example using a command such as tar -cJf archive.tar.xz directory (depending on the tar version and options).

Historically, XZ Utils was developed as an open-source implementation of the XZ format, rooted in the LZMA compression lineage originating with Igor Pavlov and later extended by contributors such as Lasse Collin. The format and tools have been adopted across Unix-like systems and remain widely used in software distributions and source packages due to their balance of high compression efficiency, streaming support, and robustness.