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BSDCPIO(1)                BSD General Commands Manual               BSDCPIO(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 overriden)
             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 overriden) 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      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      (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
             Read archive from or write archive to file.

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

     --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 format
             Synonym for --format.

     -h, --help
             Print usage information.

     -I file
             Read archive from file.

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

     -n      (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      Output mode.  See above for description.

     -p      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]
             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      (i mode only) List the contents of the archive to stdout; do not
             restore the contents to disk.

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

     -v      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.


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.


EXIT STATUS

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


EXAMPLES

     The cpio command is traditionally used to copy file heirarchies 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'' vari-
     ant, which can support files up to 8 gigabytes.

BSD                            December 21, 2007                           BSD

Mac OS X 10.7 - Generated Tue Aug 2 16:36:48 CDT 2011
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