TARArchive

TARArchive, commonly referred to as a tar archive, is a widely used archive format and the accompanying program tar. It originated on Unix in 1979 as a method to bundle multiple files for magnetic tape storage while preserving metadata such as permissions and timestamps. The name reflects its Tape Archive heritage.

A tar archive is a sequence of file entries, each consisting of a header block followed by the file data, arranged in 512-byte blocks. The standard tar format evolved into POSIX-compliant variants such as ustar and the newer Pax headers, which extend support for long file names and additional metadata. By itself, a tar file is uncompressed; compression is achieved by external tools or tar options, producing commonly seen forms such as .tar.gz (or .tgz), .tar.bz2, and .tar.xz.

Common usage involves creating, listing, and extracting archives. Typical commands in GNU tar include: tar -cvf archive.tar files/ to create, tar -tf archive.tar to list, and tar -xvf archive.tar to extract. For compressed archives, options like -z (gzip), -j (bzip2), or -J (xz) are appended, e.g., tar -czvf archive.tar.gz files/. Tar can also handle directories, symbolic and hard links, and special files, and it can preserve file permissions, ownership, and timestamps when run with appropriate privileges.

Features include support for incremental backups (-g or --listed-incremental), multi-volume archives, and the Pax extended headers for portable metadata. tar is implemented in various forms, with GNU tar being the most widespread, and is a core utility in Linux and other Unix-like systems. Given its long-standing use, tar archives remain common for software distributions, backups, and data packaging.