cpio

Create archive

$ find . -depth | cpio -o > [archive.cpio]

$ cpio -i < [archive.cpio]

$ cpio -t < [archive.cpio]

$ find . | cpio -pd [/destination]

cpio [options]

cpio (copy in/out) is an archiving utility that reads file lists from stdin and creates or extracts archives. It's commonly used in initramfs images, RPM packages, and for copying directory trees.
The tool operates in three modes: copy-out (create archives), copy-in (extract archives), and pass-through (copy files without archiving). Unlike tar, which accepts file arguments directly, cpio reads filenames from standard input, typically piped from find. This design provides greater flexibility for file selection using find's powerful filtering capabilities.
cpio is the preferred format for Linux initial ramdisk images because of its simplicity and kernel support. RPM packages use cpio internally for storing files. The format supports various archive types and can preserve file metadata including permissions, ownership, and timestamps.

-o, --create

Create archive (copy-out mode)

Extract archive (copy-in mode)

Copy files (pass-through mode)

List archive contents

Verbose mode

Create directories as needed

Overwrite files unconditionally

Preserve modification times

Copy-out (-o):

Create archive from file list

Extract from archive

Copy files without archiving

Initramfs extraction:

$ mkdir initramfs
cd initramfs
gunzip -c /boot/initramfs.img | cpio -i

$ rpm2cpio package.rpm | cpio -idmv

Less intuitive than tar. Requires file list from stdin. No built-in compression. Pathname length limits. Different behavior between GNU and POSIX versions. Not as widely used as tar.

cpio was included in Unix PWB/UNIX in 1977 and became part of POSIX, predating tar and offering more flexible file selection.

tar(1), find(1), pax(1)