
CPIO(1) 		  BSD General Commands Manual		       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 speci‐
	     fied) 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 oper‐
     ating modes.

     −0, −−null
	     Read filenames separated by NUL characters instead of newlines.
	     This is necessary if any of the filenames being read might con‐
	     tain newlines.

     −A      (o mode only) Append to the specified archive.  (Not yet imple‐
	     mented.)

     −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 for‐
		      mat.
	     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 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 orig‐
	     inal files, instead of copying.

     −−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.

     −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.	Ordi‐
	     narily, 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.  Super‐
	     seded 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 compres‐
	     sion 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 com‐
	     pression 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 compres‐
	     sion 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 con‐
     junction 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 con‐
     trol 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 partic‐
     ular 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 inter‐
     preted 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 stan‐
     dard.  For best compatibility, scripts should limit themselves to the
     standard syntax.

SEE ALSO
     bzip2(1), tar(1), gzip(1), mt(1), pax(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 for‐
     mats cannot support files over 4 gigabytes, except for the “odc” variant,
     which can support files up to 8 gigabytes.

BSD			       December 24, 2011			   BSD
