In 2001, IEEE defined a new pax format which is basically tar with additional extended attributes.
[7] Furthermore, POSIX.2 and IEEE 1003.1b drafts in 1991 cover pax command, featuring cpio and ustar archive formats.
[9] Pax command appeared in X/Open issue 4 (Single Unix Specification version 1) in 1995,[1] featuring cpio and ustar archive formats, which were also the only two formats featuring in the 1997 Single Unix Specification.
[1] pax has four general modes that are invoked by a combination of the -r ("read") and -w ("write") options.
Like tar, pax processes directory entries recursively, a feature that can be disabled with -d for cpio-style behavior.
Example for extracting a gzipped archive: As in tar and cpio, pax output can be piped to another compressor/decompressor program.
The format is not supported on most Linux distributions (whose pax command is from the MirBSD branch of MirCPIO-paxmirabilis)[10][11][12] and on FreeBSD.
Pax is also fairly chatty and expects user interactions when things go wrong.
[23][24][25] pax has also been present in Windows NT, where it is limited to file archives (tapes not supported).
[27] Packages handled by the Installer (macOS) often carry the bulk of their contents in an Archive.pax.gz file that may be read using the system's pax (heirloom) utility.