1. Computing
Linux / Unix Command: cpio
Command Library

NAME

cpio - copy files to and from archives

SYNOPSIS

cpio {-o|--create} [-0acvABLV] [-C bytes] [-H format] [-M message] [-O [[user@]host:]archive] [-F [[user@]host:]archive] [--file=[[user@]host:]archive] [--format=format] [--message=message] [--null] [--reset-access-time] [--verbose] [--dot] [--append] [--block-size=blocks] [--dereference] [--io-size=bytes] [--quiet] [--force-local] [--rsh-command=command] [--help] [--version] < name-list [> archive]

cpio {-i|--extract} [-bcdfmnrtsuvBSV] [-C bytes] [-E file] [-H format] [-M message] [-R [user][:.][group]] [-I [[user@]host:]archive] [-F [[user@]host:]archive] [--file=[[user@]host:]archive] [--make-directories] [--nonmatching] [--preserve-modification-time] [--numeric-uid-gid] [--rename] [-t|--list] [--swap-bytes] [--swap] [--dot] [--unconditional] [--verbose] [--block-size=blocks] [--swap-halfwords] [--io-size=bytes] [--pattern-file=file] [--format=format] [--owner=[user][:.][group]] [--no-preserve-owner] [--message=message] [--force-local] [--no-absolute-filenames] [--sparse] [--only-verify-crc] [--quiet] [--rsh-command=command] [--help] [--version] [pattern...] [< archive]

cpio {-p|--pass-through} [-0adlmuvLV] [-R [user][:.][group]] [--null] [--reset-access-time] [--make-directories] [--link] [--quiet] [--preserve-modification-time] [--unconditional] [--verbose] [--dot] [--dereference] [--owner=[user][:.][group]] [--no-preserve-owner] [--sparse] [--help] [--version] destination-directory < name-list

DESCRIPTION

This manual page documents the GNU version of cpio. cpio copies files into or out of a cpio or tar archive, which is a file that contains other files plus information about them, such as their file name, owner, timestamps, and access permissions. The archive can be another file on the disk, a magnetic tape, or a pipe. cpio has three operating modes.

In copy-out mode, cpio copies files into an archive. It reads a list of filenames, one per line, on the standard input, and writes the archive onto the standard output. A typical way to generate the list of filenames is with the find command; you should give find the -depth option to minimize problems with permissions on directories that are unwritable or not searchable.

In copy-in mode, cpio copies files out of an archive or lists the archive contents. It reads the archive from the standard input. Any non-option command line arguments are shell globbing patterns; only files in the archive whose names match one or more of those patterns are copied from the archive. Unlike in the shell, an initial `.' in a filename does match a wildcard at the start of a pattern, and a `/' in a filename can match wildcards. If no patterns are given, all files are extracted.

In copy-pass mode, cpio copies files from one directory tree to another, combining the copy-out and copy-in steps without actually using an archive. It reads the list of files to copy from the standard input; the directory into which it will copy them is given as a non-option argument.

cpio supports the following archive formats: binary, old ASCII, new ASCII, crc, HPUX binary, HPUX old ASCII, old tar, and POSIX.1 tar. The binary format is obsolete because it encodes information about the files in a way that is not portable between different machine architectures. The old ASCII format is portable between different machine architectures, but should not be used on file systems with more than 65536 i-nodes. The new ASCII format is portable between different machine architectures and can be used on any size file system, but is not supported by all versions of cpio; currently, it is only supported by GNU and Unix System V R4. The crc format is like the new ASCII format, but also contains a checksum for each file which cpio calculates when creating an archive and verifies when the file is extracted from the archive. The HPUX formats are provided for compatibility with HPUX's cpio which stores device files differently.

The tar format is provided for compatability with the tar program. It can not be used to archive files with names longer than 100 characters, and can not be used to archive "special" (block or character devices) files. The POSIX.1 tar format can not be used to archive files with names longer than 255 characters (less unless they have a "/" in just the right place).

By default, cpio creates binary format archives, for compatibility with older cpio programs. When extracting from archives, cpio automatically recognizes which kind of archive it is reading and can read archives created on machines with a different byte-order.

Some of the options to cpio apply only to certain operating modes; see the SYNOPSIS section for a list of which options are allowed in which modes.

OPTIONS

-0, --null
In copy-out and copy-pass modes, read a list of filenames terminated by a null character instead of a newline, so that files whose names contain newlines can be archived. GNU find is one way to produce a list of null-terminated filenames.
-a, --reset-access-time
Reset the access times of files after reading them, so that it does not look like they have just been read.
-A, --append
Append to an existing archive. Only works in copy-out mode. The archive must be a disk file specified with the -O or -F (--file) option.
-b, --swap
In copy-in mode, swap both halfwords of words and bytes of halfwords in the data. Equivalent to -sS. Use this option to convert 32-bit integers between big-endian and little-endian machines.
-B
Set the I/O block size to 5120 bytes. Initially the block size is 512 bytes.
--block-size=BLOCK-SIZE
Set the I/O block size to BLOCK-SIZE * 512 bytes.
-c
Identical to "-H newc", use the new (SVR4) portable format. If you wish the old portable (ASCII) archive format, use "-H odc" instead.
-C IO-SIZE, --io-size=IO-SIZE
Set the I/O block size to IO-SIZE bytes.
-d, --make-directories
Create leading directories where needed.
-E FILE, --pattern-file=FILE
In copy-in mode, read additional patterns specifying filenames to extract or list from FILE. The lines of FILE are treated as if they had been non-option arguments to cpio.
-f, --nonmatching
Only copy files that do not match any of the given patterns.
-F, --file=archive
Archive filename to use instead of standard input or output. To use a tape drive on another machine as the archive, use a filename that starts with `HOSTNAME:'. The hostname can be preceded by a username and an `@' to access the remote tape drive as that user, if you have permission to do so (typically an entry in that user's `~/.rhosts' file).
--force-local
With -F, -I, or -O, take the archive file name to be a local file even if it contains a colon, which would ordinarily indicate a remote host name.
-H FORMAT, --format=FORMAT
Use archive format FORMAT. The valid formats are listed below; the same names are also recognized in all-caps. The default in copy-in mode is to automatically detect the archive format, and in copy-out mode is "bin".
bin
The obsolete binary format.
odc
The old (POSIX.1) portable format.
newc
The new (SVR4) portable format, which supports file systems having more than 65536 i-nodes.
crc
The new (SVR4) portable format with a checksum added.
tar
The old tar format.
ustar
The POSIX.1 tar format. Also recognizes GNU tar archives, which are similar but not identical.
hpbin
The obsolete binary format used by HPUX's cpio (which stores device files differently).
hpodc
The portable format used by HPUX's cpio (which stores device files differently).
-i, --extract
Run in copy-in mode.
-I archive
Archive filename to use instead of standard input. To use a tape drive on another machine as the archive, use a filename that starts with `HOSTNAME:'. The hostname can be preceded by a username and an `@' to access the remote tape drive as that user, if you have permission to do so (typically an entry in that user's `~/.rhosts' file).
-k
Ignored; for compatibility with other versions of cpio.
-l, --link
Link files instead of copying them, when possible.
-L, --dereference
Dereference symbolic links (copy the files that they point to instead of copying the links).
-m, --preserve-modification-time
Retain previous file modification times when creating files.
-M MESSAGE, --message=MESSAGE
Print MESSAGE when the end of a volume of the backup media (such as a tape or a floppy disk) is reached, to prompt the user to insert a new volume. If MESSAGE contains the string "%d", it is replaced by the current volume number (starting at 1).
-n, --numeric-uid-gid
In the verbose table of contents listing, show numeric UID and GID instead of translating them into names. Also extracts tar archives using the numeric UID and GID instead of the user/group names. (cpio archives are always extracted using the numeric UID and GID.)
--no-absolute-filenames
In copy-in mode, create all files relative to the current directory, even if they have an absolute file name in the archive.
--no-preserve-owner
In copy-in mode and copy-pass mode, do not change the ownership of the files; leave them owned by the user extracting them. This is the default for non-root users, so that users on System V don't inadvertantly give away files.
-o, --create
Run in copy-out mode.
-O archive
Archive filename to use instead of standard output. To use a tape drive on another machine as the archive, use a filename that starts with `HOSTNAME:'. The hostname can be preceded by a username and an `@' to access the remote tape drive as that user, if you have permission to do so (typically an entry in that user's `~/.rhosts' file).
--only-verify-crc
When reading a CRC format archive in copy-in mode, only verify the CRC's of each file in the archive, don't actually extract the files.
-p, --pass-through
Run in copy-pass mode.
--quiet
Do not print the number of blocks copied.
-r, --rename
Interactively rename files.
-R [user][:.][group], --owner [user][:.][group]
In copy-out and copy-pass modes, set the ownership of all files created to the specified user and/or group. Either the user or the group, or both, must be present. If the group is omitted but the ":" or "." separator is given, use the given user's login group. Only the super-user can change files' ownership.
--rsh-command=COMMAND
Notifies mt that it should use COMMAND to communicate with remote devices instead of /usr/bin/ssh or /usr/bin/rsh.
--sparse
In copy-in and copy-pass modes, write files with large blocks of zeros as sparse files.
-s, --swap-bytes
In copy-in mode, swap the bytes of each halfword (pair of bytes) in the files.
-S, --swap-halfwords
In copy-in mode, swap the halfwords of each word (4 bytes) in the files.
-t, --list
Print a table of contents of the input.
-u, --unconditional
Replace all files, without asking whether to replace existing newer files with older files.
-v, --verbose
List the files processed, or with -t, give an `ls -l' style table of contents listing. In a verbose table of contents of a ustar archive, user and group names in the archive that do not exist on the local system are replaced by the names that correspond locally to the numeric UID and GID stored in the archive.
-V --dot
Print a "." for each file processed.
--version
Print the cpio program version number and exit.


Important: Use the man command (% man) to see how a command is used on your particular computer.

>> Linux/Unix Command Library

>> Shell Command Library

Discuss in my forum

©2014 About.com. All rights reserved.