CPIO(1) User Commands CPIO(1)

NAME

cpio - copy files to and from archives

SYNOPSIS

cpio -i [options] [pattern ...] [< archive]
cpio -o [options] < name-list [> archive]
cpio -p [options] dest-dir < name-list

DESCRIPTION

cpio copies files between archives and directories. This
implementation can extract from tar, pax, cpio, zip, jar, ar, and ISO
9660 cdrom images and can create tar, pax, cpio, ar, and shar archives.

The first option to cpio is a mode indicator from the following list:
-i Input. Read an archive from standard input (unless overridden)
and extract the contents to disk or (if the -t option is
specified) list the contents to standard output. If one or
more file patterns are specified, only files matching one of
the patterns will be extracted.
-o Output. Read a list of filenames from standard input and
produce a new archive on standard output (unless overridden)
containing the specified items.
-p Pass-through. Read a list of filenames from standard input and
copy the files to the specified directory.

OPTIONS

Unless specifically stated otherwise, options are applicable in all
operating modes.

-0, --null
Read filenames separated by NUL characters instead of newlines.
This is necessary if any of the filenames being read might
contain newlines.

-6, --pwb
When reading a binary format archive, assume it's the earlier
one, from the PWB variant of 6th Edition UNIX. When writing a
cpio archive, use the PWB format.

-7, --binary
(o mode only) When writing a cpio archive, use the (newer, non-
PWB) binary format.

-A (o mode only) Append to the specified archive. (Not yet
implemented.)

-a (o and p modes) Reset access times on files after they are
read.

-B (o mode only) Block output to records of 5120 bytes.

-C size
(o mode only) Block output to records of size bytes.

-c (o mode only) Use the old POSIX portable character format.
Equivalent to --format odc.

-d, --make-directories
(i and p modes) Create directories as necessary.

-E file
(i mode only) Read list of file name patterns from file to list
and extract.

-F file, --file file
Read archive from or write archive to file.

-f pattern
(i mode only) Ignore files that match pattern.

-H format, --format format
(o mode only) Produce the output archive in the specified
format. Supported formats include:

cpio Synonym for odc.
newc The SVR4 portable cpio format.
odc The old POSIX.1 portable octet-oriented cpio format.
pax The POSIX.1 pax format, an extension of the ustar
format.
ustar The POSIX.1 tar format.

The default format is odc. See libarchive-formats(5) for more
complete information about the formats currently supported by
the underlying libarchive(3) library.

-h, --help
Print usage information.

-I file
Read archive from file.

-i, --extract
Input mode. See above for description.

--insecure
(i and p mode only) Disable security checks during extraction
or copying. This allows extraction via symbolic links,
absolute paths, and path names containing `..' in the name.

-J, --xz
(o mode only) Compress the file with xz-compatible compression
before writing it. In input mode, this option is ignored; xz
compression is recognized automatically on input.

-j Synonym for -y.

-L (o and p modes) All symbolic links will be followed. Normally,
symbolic links are archived and copied as symbolic links. With
this option, the target of the link will be archived or copied
instead.

-l, --link
(p mode only) Create links from the target directory to the
original files, instead of copying.

--lrzip
(o mode only) Compress the resulting archive with lrzip(1). In
input mode, this option is ignored.

--lz4 (o mode only) Compress the archive with lz4-compatible
compression before writing it. In input mode, this option is
ignored; lz4 compression is recognized automatically on input.

--zstd (o mode only) Compress the archive with zstd-compatible
compression before writing it. In input mode, this option is
ignored; zstd compression is recognized automatically on input.

--lzma (o mode only) Compress the file with lzma-compatible
compression before writing it. In input mode, this option is
ignored; lzma compression is recognized automatically on input.

--lzop (o mode only) Compress the resulting archive with lzop(1). In
input mode, this option is ignored.

--passphrase passphrase
The passphrase is used to extract or create an encrypted
archive. Currently, zip is only a format that cpio can handle
encrypted archives. You shouldn't use this option unless you
realize how insecure use of this option is.

-m, --preserve-modification-time
(i and p modes) Set file modification time on created files to
match those in the source.

-n, --numeric-uid-gid
(i mode, only with -t) Display numeric uid and gid. By
default, cpio displays the user and group names when they are
provided in the archive, or looks up the user and group names
in the system password database.

--no-preserve-owner
(i mode only) Do not attempt to restore file ownership. This
is the default when run by non-root users.

-O file
Write archive to file.

-o, --create
Output mode. See above for description.

-p, --pass-through
Pass-through mode. See above for description.

--preserve-owner
(i mode only) Restore file ownership. This is the default when
run by the root user.

--quiet
Suppress unnecessary messages.

-R [user][:][group], --owner [user][:][group]
Set the owner and/or group on files in the output. If group is
specified with no user (for example, -R :wheel) then the group
will be set but not the user. If the user is specified with a
trailing colon and no group (for example, -R root:) then the
group will be set to the user's default group. If the user is
specified with no trailing colon, then the user will be set but
not the group. In -i and -p modes, this option can only be
used by the super-user. (For compatibility, a period can be
used in place of the colon.)

-r (All modes.) Rename files interactively. For each file, a
prompt is written to /dev/tty containing the name of the file
and a line is read from /dev/tty. If the line read is blank,
the file is skipped. If the line contains a single period, the
file is processed normally. Otherwise, the line is taken to be
the new name of the file.

-t, --list
(i mode only) List the contents of the archive to stdout; do
not restore the contents to disk.

-u, --unconditional
(i and p modes) Unconditionally overwrite existing files.
Ordinarily, an older file will not overwrite a newer file on
disk.

-V, --dot
Print a dot to stderr for each file as it is processed.
Superseded by -v.

-v, --verbose
Print the name of each file to stderr as it is processed. With
-t, provide a detailed listing of each file.

--version
Print the program version information and exit.

-y (o mode only) Compress the archive with bzip2-compatible
compression before writing it. In input mode, this option is
ignored; bzip2 compression is recognized automatically on
input.

-Z (o mode only) Compress the archive with compress-compatible
compression before writing it. In input mode, this option is
ignored; compression is recognized automatically on input.

-z (o mode only) Compress the archive with gzip-compatible
compression before writing it. In input mode, this option is
ignored; gzip compression is recognized automatically on input.

EXIT STATUS

The cpio utility exits 0 on success, and >0 if an error occurs.

ENVIRONMENT

The following environment variables affect the execution of cpio:

LANG The locale to use. See environ(7) for more information.

TZ The timezone to use when displaying dates. See
environ(7) for more information.

EXAMPLES

The cpio command is traditionally used to copy file hierarchies in
conjunction with the find(1) command. The first example here simply
copies all files from src to dest:
find src | cpio -pmud dest

By carefully selecting options to the find(1) command and combining it
with other standard utilities, it is possible to exercise very fine
control over which files are copied. This next example copies files
from src to dest that are more than 2 days old and whose names match a
particular pattern:
find src -mtime +2 | grep foo[bar] | cpio -pdmu dest

This example copies files from src to dest that are more than 2 days
old and which contain the word "foobar":
find src -mtime +2 | xargs grep -l foobar | cpio -pdmu dest

COMPATIBILITY

The mode options i, o, and p and the options a, B, c, d, f, l, m, r, t,
u, and v comply with SUSv2.

The old POSIX.1 standard specified that only -i, -o, and -p were
interpreted as command-line options. Each took a single argument of a
list of modifier characters. For example, the standard syntax allows
-imu but does not support -miu or -i -m -u, since m and u are only
modifiers to -i, they are not command-line options in their own right.
The syntax supported by this implementation is backwards-compatible
with the standard. For best compatibility, scripts should limit
themselves to the standard syntax.

SEE ALSO

bzip2(1), gzip(1), mt(1), pax(1), tar(1), libarchive(3), cpio(5),
libarchive-formats(5), tar(5)

STANDARDS

There is no current POSIX standard for the cpio command; it appeared in
ISO/IEC 9945-1:1996 ("POSIX.1") but was dropped from IEEE Std
1003.1-2001 ("POSIX.1").

The cpio, ustar, and pax interchange file formats are defined by IEEE
Std 1003.1-2001 ("POSIX.1") for the pax command.

HISTORY

The original cpio and find utilities were written by Dick Haight while
working in AT&T's Unix Support Group. They first appeared in 1977 in
PWB/UNIX 1.0, the "Programmer's Work Bench" system developed for use
within AT&T. They were first released outside of AT&T as part of
System III Unix in 1981. As a result, cpio actually predates tar, even
though it was not well-known outside of AT&T until some time later.

This is a complete re-implementation based on the libarchive(3)
library.

BUGS

The cpio archive format has several basic limitations: It does not
store user and group names, only numbers. As a result, it cannot be
reliably used to transfer files between systems with dissimilar user
and group numbering. Older cpio formats limit the user and group
numbers to 16 or 18 bits, which is insufficient for modern systems.
The cpio archive formats cannot support files over 4 gigabytes, except
for the "odc" variant, which can support files up to 8 gigabytes.

illumos September 16, 2014 illumos