Like RunConvert? Set us as a preferred source on Google.What is a CPIO file?
Copy In, Copy Out
- Developed By
- AT&T / Bell Labs
- Initial Release
- 1977
- MIME Type
- application/x-cpio
The CPIO (Copy In, Copy Out) format is a binary or ASCII archive file format used predominantly in Unix-like operating systems for backing up and transferring files between disparate systems. Originally defined as part of the Programmer's Workbench (PWB/UNIX) and later standardized in POSIX.1 (IEEE Std 1003.1-1988), CPIO archives store file metadata-including inode numbers, user IDs, and timestamps-alongside the raw data stream. Unlike TAR, CPIO handles non-tape media and special files more robustly but requires specific headers (binary, old ASCII, or new ASCII/CRC) to ensure compatibility across System V and BSD-derived kernels.
How to open a CPIO file
Native extraction of CPIO archives is standard on Linux and macOS distributions via the GNU cpio or pax command-line utilities (e.g., cpio -idv < archive.cpio). For Windows environments, which lack kernel-level support for POSIX archiving tools, users must utilize third-party decompression software such as 7-Zip or PeaZip, which implement the necessary decoders to interpret the CPIO header structures and extract the contained file hierarchy.