Pax (command)

pax
Original author(s)Mark H. Colburn (sponsored by The USENIX Association)
Developer(s)Various open-source and commercial developers
Initial release1989; 35 years ago (1989)
Written inColburn pax, Muller pax, Heirloom Project pax: C
Operating systemUnix, Unix-like, IBM i, Windows
PlatformCross-platform
TypeCommand
LicenseColburn pax: Prior BSD License
Muller pax: BSD-4-Clause
Heirloom Project pax: zlib
Windows: Proprietary software

pax is an archiving utility available for various operating systems and defined since 1995.[1] Rather than sort out the incompatible options that have crept up between tar and cpio, along with their implementations across various versions of Unix, the IEEE designed a new archive utility pax that could support various archive formats with useful options from both archivers. The pax command is available on Unix and Unix-like operating systems and on IBM i,[2] and Microsoft Windows NT[3] until Windows 2000.

In 2001, IEEE defined a new pax format which is basically tar with additional extended attributes.[4][5] The format is not supported by pax commands in most Linux distributions and in FreeBSD, but it is supported by tar commands from GNU and FreeBSD; the format is further supported by pax commands in AIX, Solaris and HP-UX.

The name "pax" is an acronym for portable archive exchange, but is also an allusion to the Latin word for "peace"; the command invocation and structure represents somewhat of a peaceful unification of both tar and cpio.

  1. ^ The Open Group Base Specifications Issue 6 - POSIX.1-2001 (IEEE Std 1003.1) Copyright © 2001-2004 The IEEE and The Open Group
  2. ^ IBM. "IBM System i Version 7.2 Programming Qshell" (PDF). IBM. Retrieved 2020-09-05.
  3. ^ Cite error: The named reference Pearce1997 was invoked but never defined (see the help page).
  4. ^ "GNU tar: 8.1 Using Less Space through Compression". www.gnu.org. Archived from the original on 6 March 2016. Retrieved 22 April 2018.
  5. ^ "GNU tar: 4.3.2 Extended File Attributes". www.gnu.org. Archived from the original on 28 December 2019. Retrieved 27 January 2021.