TAR
Tape archive from 1979 that Linux can't live without.
Where it came from
TAR ('tape archive') appeared in Version 7 Unix (1979) for sequential backup to magnetic tape — hence fixed 512-byte blocks, which tape drives loved. POSIX standardized the ustar variant in 1988.
Unix philosophy kept TAR dumb: it concatenates files and metadata but doesn't compress. Compression came from outside — compress, later gzip, bzip2, xz — giving the world .tar.gz.
How it works
Each entry is a 512-byte header (name, mode, size in octal ASCII, checksum) followed by data padded to 512-byte multiples; two zero blocks end the archive. The ustar extension adds a prefix field for long paths.
No compression, no central directory — just a stream. That simplicity is why a correct parser is ~70 lines and why tar is the wrapper of choice for package formats (deb, RPM payloads).
Path traversal (`../` in names) is the classic TAR vulnerability — extractors must normalize paths. UWC parses TAR in your browser and shows entries before you download anything.
Unpack TAR archives
List and extract .tar files locally — including the ones inside .tar.gz bundles.