Provided by: libarchive-tools_3.6.2-1ubuntu1.1_amd64 
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.