pax is an archiving utility created by POSIX and defined by the POSIX.1-2001 standard. By default, it creates archives in ustar format, also defined by the POSIX standard. The name “pax” is an acronym for Portable Archive Exchange. Furthermore, “pax” means “peace” in Latin, so its name implies that it shall create peace between the tar and cpio format supporters. The command invocation and command structure is somewhat a unification of both tar and cpio.