GNU cpio

 [image of the Head of a GNU]

Introduction to cpio

GNU cpio copies files into or out of a cpio or tar archive. The archive can be another file on the disk, a magnetic tape, or a pipe.

GNU cpio supports the following archive formats: binary, old ASCII, new ASCII, crc, HPUX binary, HPUX old ASCII, old tar, and POSIX.1 tar. The tar format is provided for compatibility with the tar program. By default, cpio creates binary format archives, for compatibility with older cpio programs. When extracting from archives, cpio automatically recognizes which kind of archive it is reading and can read archives created on machines with a different byte-order.

Downloading cpio

Cpio can be found on the main GNU ftp server (download Cpio via HTTPSdownload Cpio via HTTP or download Cpio via FTP), and its mirrors; please use a mirror if possible.

The project's homepage at Savannah is the place to look for the latest news and patches for the project.


Documentation for cpio is online, as is documentation for most GNU software. It can also be accessed by running info cpio or man cpio, or by looking at /usr/share/doc/cpio/, or similar directories on your system. A brief summary is available by running cpio --help.

Mailing lists

Cpio has the following mailing lists:

Announcements about cpio and most other GNU software are made on the info-gnu mailing list (archives).

Security reports that should not be made immediately public can be sent directly to the maintainer. If there is no response to an urgent issue, you can escalate to the general security mailing list for advice.

Getting involved

Development of cpio, and GNU in general, is a volunteer effort, and you can contribute. For information, please read How to help GNU. If you'd like to get involved, it's a good idea to join the discussion mailing list (see above).

Development tools
For development sources, issue trackers, and other information, please see the cpio project page at
Trying the latest test release (when available) is always appreciated. Test releases can be found on the GNU “alpha” server (HTTPSHTTPFTP) and its mirrors.
To translate the program messages into other languages, please refer to the Translation Project page for cpio. New translations or updates to the existing strings will not be incorporated into cpio if they are sent elsewhere. For more information, see the Translation Project home page.
Cpio is currently maintained by Sergey Poznyakoff. Please use the mailing lists for contact.


Cpio is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version.