Man pages › Compared with Linux and the BSDs

`cpio(1)` on Solnix vs Linux and the BSDs

On Solnix, cpio is the illumos cpio at /usr/bin/cpio. It has only short options, no -0, no -F and no built-in compression. Scripts written for GNU cpio or the libarchive cpio on FreeBSD and NetBSD (find -print0 | cpio -0, -F archive, --format, -J/-z) will fail on it.

The manual pages

Solnix: cpio(1) from pkgs.solnix.illumos-world-man · illumos.org
Linux: cpio(1) cpio-2.15
FreeBSD: cpio(1) 15.1-RELEASE
OpenBSD: cpio(1) 8.0
NetBSD: cpio(1) 11.0

What Solnix runs

A default Solnix system runs the illumos cpio at /usr/bin/cpio. No other variants are shipped. The Solnix page text in the bundle is trimmed, so the meanings of some options (-k, -P, -@, -/, -V, -q, -s, -S) and the default header format are not visible here.

Differences

Compared with	Topic	What differs
Linux, FreeBSD, NetBSD	NUL-separated file names (`-0`)	Solnix cpio has no `-0` or `--null` in its synopsis, so it cannot read NUL-separated names. Linux, FreeBSD and NetBSD accept `-0`/-`-null` for names that may contain newlines. OpenBSD has no `-0` either. Source: Solnix cpio(1) SYNOPSIS; Linux cpio(1) -0, --null; FreeBSD cpio(1) -0, --null; NetBSD cpio(1) -0, --null
all four	archive file option (`-F`)	Solnix names the archive with `-I` (read) and `-O` (write), and has no `-F`. Linux, FreeBSD, NetBSD and OpenBSD all accept `-F` to read or write the archive file. FreeBSD and NetBSD also give `--file`. Source: Solnix cpio(1) SYNOPSIS (-I, -O); Linux cpio(1) -F, --file; FreeBSD cpio(1) -F; NetBSD cpio(1) -F; OpenBSD cpio(1) -F archive
Linux, FreeBSD, NetBSD	long options	Solnix cpio has only single-letter options. Linux, FreeBSD and NetBSD cpio also take long options such as `--create`, `--extract`, `--format`, `--make-directories` and `--quiet`. Source: Solnix cpio(1) SYNOPSIS; Linux cpio(1) SYNOPSIS; FreeBSD cpio(1) OPTIONS; NetBSD cpio(1) OPTIONS
all four	`-H` format names	Solnix `-H` accepts bar (read only), crc\|CRC, odc, tar\|TAR and ustar\|USTAR in the visible text, with no newc. Linux accepts bin, odc, newc, crc, tar, ustar, hpbin and hpodc. FreeBSD and NetBSD list cpio, newc, odc, pax and ustar. OpenBSD lists bcpio, cpio, pax, sv4cpio, tar and ustar. Source: Solnix cpio(1) -H header; Linux cpio(1) -H; FreeBSD cpio(1) -H; NetBSD cpio(1) -H; OpenBSD cpio(1) -o -H format
FreeBSD, OpenBSD, NetBSD	format named "cpio"	A `-H` argument of cpio means odc on FreeBSD and NetBSD, and the old octal character format on OpenBSD. The Solnix text has no format called cpio. Its portable ASCII choices are `-H` odc (IEEE/P1003) and crc. Source: FreeBSD cpio(1) -H (cpio: synonym for odc); NetBSD cpio(1) -H; OpenBSD cpio(1) -H (cpio: old octal character cpio format); Solnix cpio(1) -H header
Linux, FreeBSD, NetBSD	`-c` meaning	On Solnix, `-c` writes the SVR4 ASCII header with expanded device numbers. For unknown machines the page says to use `-H` odc instead. On Linux, FreeBSD and NetBSD, `-c` is the old POSIX portable (odc) format, the same as `-H` odc or `--format` odc. Source: Solnix cpio(1) -c; Linux cpio(1) -c; FreeBSD cpio(1) -c; NetBSD cpio(1) -c
Linux, OpenBSD	`-b` meaning	Solnix `-b` reverses the byte order within each word and works only with `-i`. Linux `-b` swaps both halfwords and bytes (equivalent to `-sS`). OpenBSD `-b` does byte and word swapping on read. FreeBSD and NetBSD have no `-b`. Source: Solnix cpio(1) -b; Linux cpio(1) -b, --swap; OpenBSD cpio(1) -i -b; FreeBSD cpio(1) OPTIONS; NetBSD cpio(1) OPTIONS
FreeBSD, OpenBSD, NetBSD	compression options	Solnix cpio has no compression options. FreeBSD and NetBSD offer `-J`, `-j`, `-y`, `-z`, `-Z` and `--lz4`, `--zstd`, `--lzma`, `--lzop` and `--lrzip`. OpenBSD offers `-j` (bzip2, installed separately), `-Z` (compress) and `-z` (gzip). Source: Solnix cpio(1) SYNOPSIS; FreeBSD cpio(1) -J, -j, --lz4, --zstd; NetBSD cpio(1) -J, --lzma; OpenBSD cpio(1) -j, -Z, -z
FreeBSD, NetBSD	archive types read and written	FreeBSD and NetBSD cpio use libarchive. They read tar, pax, cpio, zip, jar, ar and ISO 9660 images and write tar, pax, cpio, ar and shar. The Solnix text lists only the `-H` header formats bar, crc, odc, tar and ustar. Source: FreeBSD cpio(1) DESCRIPTION; NetBSD cpio(1) DESCRIPTION; Solnix cpio(1) -H header
FreeBSD, NetBSD	append (`-A`)	On Solnix, `-A` appends to an archive, requires `-O`, and is valid only for archives that are files, floppy diskettes or hard disk partitions. FreeBSD and NetBSD document `-A` as not yet implemented. Source: Solnix cpio(1) -A; FreeBSD cpio(1) -A; NetBSD cpio(1) -A
FreeBSD, NetBSD	restoring ownership	Solnix cpio `-i` gives files the current user's owner and group unless that user has the {PRIV_FILE_CHOWN_SELF} privilege. FreeBSD and NetBSD restore ownership by default for root (`--preserve-owner`) and not for other users (`--no-preserve-owner`). Source: Solnix cpio(1) Copy In Mode; FreeBSD cpio(1) --preserve-owner, --no-preserve-owner; NetBSD cpio(1) --preserve-owner, --no-preserve-owner
Linux	`-R` in copy-out, `-n` and `-D`	The Solnix synopsis shows `-R` only for `-i` and `-p`. Linux `-R` also works in copy-out, where it stores the owner in the archive. Solnix has no `-n` (numeric uid/gid in a listing) and no `-D` directory option, which Linux has. Source: Solnix cpio(1) SYNOPSIS; Linux cpio(1) -R, --owner, -n, -D

Standards

POSIX: cpio is not a POSIX.1-2024 utility.
Solnix: The page describes -H odc as the IEEE/P1003 Data Interchange Standard cpio header and format, and the official format for transferring files between POSIX-conforming systems (see standards(7)).
Linux: -H odc is described as the old (POSIX.1) portable format.
FreeBSD: odc is described as the old POSIX.1 portable octet-oriented cpio format; ustar as the POSIX.1 tar format.

Writing portable scripts

Use -H odc when the archive must be read on Solnix, Linux, FreeBSD and NetBSD. Do not use -H newc or -H bar: the visible Solnix text has no newc, and bar is read-only.
Do not use -0, -F, long options or compression flags in a portable script. Feed names on stdin separated by newlines and redirect the archive with < and >, then compress with a separate tool.

Every difference here is taken from the manual pages linked above: Solnix's published page, Linux (man-pages and the GNU and util-linux manuals), FreeBSD, OpenBSD and NetBSD. Each row names its source. Where a manual is silent, this page is too. Compiled 2026-10-26. Found a mistake? Mail hackers@lists.solnix.io.