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.

     -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.

     --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.

     -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), 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
     formats cannot support files over 4 gigabytes, except for the “odc” variant, which can
     support files up to 8 gigabytes.