cpio —
copy
files to and from archives
| cpio |
-i
[options]
[pattern ...]
[<
archive] |
| cpio |
-o
[options]
< name-list
[>
archive] |
| cpio |
-p
[options]
dest-dir <
name-list
|
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.
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.
The
cpio utility exits 0 on success,
and >0 if an error occurs.
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.
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
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.
bzip2(1),
gzip(1),
mt(1),
pax(1),
tar(1),
libarchive(3),
cpio(5),
libarchive-formats(5),
tar(5)
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.
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.
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.