pax is an archiving utility available for various operating systems and defined since 1995. 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 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, and Microsoft Windows NT until Windows 2000. In 2001, IEEE defined a new pax format which is basically tar with additional extended attributes. 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. The command invocation and structure is somewhat a unification of both tar and cpio. History The first public implementation of pax was written by Mark H. Colburn in 1989. Colburn posted it to as Usenix/IEEE POSIX replacement for TAR and CPIO. Manual pages for pax on HP-UX, IRIX, and SCO UNIX attribute pax to Colburn. As early as POSIX.2 draft 10 from July 1990 covers pax command. Furthermore, POSIX.2 and IEEE 1003.1b drafts in 1991 cover pax command, featuring cpio and ustar archive formats. Another version of the pax program was created by Keith Muller in 1992–1993. The version first appeared in 4.4BSD (1995). Pax command appeared in X/Open issue 4 (Single Unix Specification version 1) in 1995, featuring cpio and ustar archive formats, which were also the only two formats featuring in the 1997 Single Unix Specification. In 1997, Sun Microsystems proposed a method for adding extensions to the ustar format. This method was accepted for the POSIX.1-2001 standard as the new pax file format. The POSIX specification for the utility was updated to include this format. Features Modes pax has four general modes that are invoked by a combination of the ("read") and ("write") options. This table summarizes the modal behaviour: This model is similar to cpio, which has a similar set of basic operations. Examples List contents of an archive: Extract contents of an archive into the current directory: Create an archive of the current directory: Copy current directory tree to another location: (The target directory must exist beforehand!) Command invocation By default,