| Original author(s) | Dick Haight |
|---|---|
| Developer(s) | AT&T Bell Laboratories |
| Initial release | 1977 |
| Operating system | Unix and Unix-like |
| Type | Command |
| License | GNU cpio: GPLv3 libarchive bsdcpio: New BSD License |
| Filename extension |
.cpio |
|---|---|
| Internet media type |
application/x-cpio |
| Uniform Type Identifier (UTI) | public.cpio-archive |
| Type of format | File archiver |
cpio is a general file archiver utility and its associated file format. It is primarily installed on Unix-like computer operating systems. The software utility was originally intended as a tape archiving program as part of the Programmer's Workbench (PWB/UNIX), and has been a component of virtually every Unix operating system released thereafter. Its name is derived from the phrase copy in and out, in close description of the program's use of standard input and standard output in its operation.
All variants of Unix also support other backup and archiving programs, such as tar, which has become more widely recognized.[1] The use of cpio by the RPM Package Manager, in the initramfs of the Linux kernel since version 2.6, and in Apple's Installer (pax) make cpio an important archiving tool.
Since its original design, cpio and its archive file format have undergone several, sometimes incompatible, revisions. Most notable is the change, now an operational option, from the use of a binary format of archive file meta information to an ASCII-based representation.
cpio was removed from POSIX.1-2001 in favor of pax,[2] a similar utility which had been introduced in the previous version of the standard.