cpio -- copy file archives in and out
/u95/bin/cpio -i [ bBcdfkmrsSTtuvV6 ] [-C bufsize ] [ -E file ] [ -G fi
le ] [ -H hdr ]
[ -e [xattr_name=]action[,[xattr_name=]action ...]
[ -I file [-M message] ] [-R ID] ] [ pattern ...]
cpio -o [ aABcLvV ] [ -C bufsize] [-G file] [-H hdr ] [ -K mediasize ]
[ -e [xattr_name=]action[,[xattr_name=]action ... ]
[ -O file [-M message] ]
cpio -p directory |[adlLmuvV] [-R ID]
[-e [xattr_name=]action[,[xattr_name=]action ...]
The -i, -o, and -p options select the action to be performed. The
following list describes each of the actions (which are mutually
cpio -i (copy in) extracts files from the standard input (only if
-I is not specified), which is assumed to be the product of a
previous cpio -o. Only files with names that match patterns are
selected. patterns are regular expressions given in the
filename-generating notation of sh(1). In patterns,
meta-characters ``?'', `` * '', and ``[ . . . ]'' match the slash
(``/'') character, and backslash (``\'') is an escape character.
A ``!'' meta-character means not. (For example, the ``!abc * ''
pattern would exclude all files that begin with ``abc''.)
Multiple patterns may be specified and if no patterns are
specified, the default for patterns is `` * '' (that is, select
all files). Each pattern must be enclosed in double quotes;
otherwise, the name of a file in the current directory might be
used. Extracted files are conditionally created and copied into
the current directory tree based on the options described below.
The permissions of the files will be those of the previous cpio
-o. Owner and group permissions will be the same as the current
user unless the current user possesses the owner privilege. If
this is true, owner and group permissions will be the same as
those resulting from the previous cpio -o.
NOTE: If cpio -i tries to create a file that already exists and
the existing file is the same age or younger (newer), cpio will
output a warning message and not replace the file.
(The -u option can be used to overwrite, unconditionally, the
existing file.) If file names are given as absolute pathnames to
cpio -o, then when the files are restored via cpio -i, they will
be written to their original directories regardless of the
current directory. This behavior can be circumvented by using the
-r option. When cpio is invoked from the shell, each pattern
should be quoted.
In normal circumstances, cpio sets the Hdr_type variable (which
defines the header type) to NONE before checking the actual
header type. It does this even if you have specified a different
header type on the command line. When you use the -k option,
however, cpio does not set Hdr_type to NONE if you've specified a
header type on the command line (with the -c or -H option). In
this case, cpio sets Hdr_type to the header type you've
specified. Thus you have a way of making sure the correct header
file type is specified, which improves your chances of recovering
files correctly. For this reason, we recommend you specify the
header type for the file (with -c or -H) whenever you use the -k
cpio -o (copy out) reads the standard input to obtain a list of
pathnames and copies those files onto the standard output (only
if the -O is not specified) together with pathname and status
cpio -p (pass) reads the standard input to obtain a list of
pathnames of files that are conditionally created and copied into
the destination directory tree based on the options described
By default, cpio also attempts to copy extended attribute
information on the source to the target. Extended attribute
* Access Control Lists (ACLs)
* Veritas file system type (vxfs) file system attributes
The cpio command issues a warning if existing extended attribute
information on the source cannot be copied to the destination
(unless other actions are specified for extended attributes via
the -e option).
cpio processes supplementary code set characters, and recognizes
supplementary code set characters in the message given to the -M
option (see below) according to the locale specified in the
LC_CTYPE environment variable (see LANG on environ(5)). In
regular expressions, pattern searches are performed on
characters, not bytes, as described on sh(1). Under the -vt
option (see below), the date is displayed according to the locale
specified in the LC_TIME environment variable.
The meanings of the available options are
Reset access times of input files after they have been
copied. Access times are not reset for linked files when
cpio -pla is specified.
Append files to an archive. The -A option requires the -O
option. Valid only with archives that are files, or that
are on floppy diskettes or hard disk partitions.
Reverse the order of the bytes within each word. (Use only
with the -i option.)
Input/output is to be blocked 5120 bytes to the record.
The default buffer size is device dependent when neither
this nor the -C option is used.
Read or write header information in ASCII character form
for portability. Always use this option (or the -H option)
when the origin and the destination machines are different
types (mutually exclusive with -H and -6). (The -c option
implies expanded fundamental types. See ``Notices'' for
This option (or -H hdr) must be specified if the file to
be copied in or out is larger than 2GB.
Input/output is to be blocked bufsize bytes to the record,
where bufsize is replaced by a positive integer. The
default buffer size is device dependent when neither this
nor the -B option is used. If used with -K, bufsize must
be a multiple of 1K.
Directories are to be created as needed.
Specify an input file (file) that contains a list of
filenames to be extracted from the archive (one filename
[-e [xattr_name=]action[,[xattr_name=]action . . .]
Specify how to handle various extended file attributes.
The following are the valid parameters for xattr_name and
the extended attribute information to which they refer:
Access Control Lists (ACLs) on the source files and
Privileges on the source files and directories
Extent attributes include reserved space, a fixed
extent size, and extent alignment. It may not be
possible to preserve the information if the
destination file system does not support extent
attributes, has a different block size than the
source file system, or lacks free extents appropriate
to satisfy the extent attribute requirements.
Can be used only on restore (cpio -i), and specifies
how to deal with extended file attributes not
recognized by the current version of cpio.
Refers to all extended attribute information for each
file or directory processed.
Valid values for action are:
Issue a warning message if extent attribute
information cannot be kept (default).
Fail the file save or restore or copy if extent
attribute information cannot be kept.
Ignore extent attribute information entirely.
For more information on extended attributes, see
Copy in all files except those in patterns (See the
paragraph about cpio -i for a description of patterns.)
NOTE: This option is intended for use by front-end or
application programs that invoke cpio. If you're running
cpio at the shell level, you probably won't need this
The -G option allows a program to specify file as the
interface through which cpio communicates with a user.
Specifically, this interface is used for end-of-medium
processing (but it also affects where -r gets done); it is
used both for writing the prompts to the user and for
reading the user's input. By default, /dev/tty is the
interface. However, in some situations (such as graphics
application environments), /dev/tty is not available.
Therefore an alternative interface, such as a pseudo-tty,
may be needed.
If the argument to -G is the keyword STDIO, it will print
prompts (to change the media, and also for new file names
when the -r option is used) on stdout, and read responses
Read or write header information in hdr format. Always use
this option or the -c option when the origin and the
destination machines are different types (mutually
exclusive with -c and -6). Valid values for hdr are:
crc or CRC
ASCII header with expanded fundamental types and an
additional per-file checksum. See ``Notices'' for
The crc file format has been updated to handle files
larger than 2GB.
ustar or USTAR
IEEE/P1003 Data Interchange Standard header and
tar or TAR
tar header and format
ASCII header with small fundamental types (see
Read the contents of file as an input archive. If file is
a character special device, and the current medium has
been completely read, replace the medium and press
<Return> to continue to the next medium. This option is
used only with the -i option.
Attempt to skip corrupted file headers and I/O errors that
may be encountered. If you want to copy files from a
medium that is corrupted or out of sequence, this option
lets you read only those files with good headers. (For
cpio archives that contain other cpio archives, if an
error is encountered, cpio may terminate prematurely. cpio
will find the next good header, which may be one for a
smaller archive, and terminate when the smaller archive's
trailer is encountered.) Used only with the -i option.
Specify the media size as a multiple of 1K. If used with
-C bufsize, then bufsize must be a multiple of 1K. Use
only with the -o option.
Whenever possible (only with the -p option), link files
rather than copying them. (Even if a file cannot be
linked, it will be copied.)
Follow symbolic links. The default is not to follow
Retain previous file modification time. The modification
time and access time of a restored file is set to the
modification time of the file when it was backed up.
Modification time of directories is not retained.
Define a message to use when switching media. When you use
the -O or -I options and specify a character special
device, you can use this option to define the message that
is printed when you reach the end of the medium. One %d
can be placed in message to print the sequence number of
the next medium needed to continue. message may contain
supplementary code set characters.
Direct the output of cpio to file. If file is a character
special device and the current medium is full, replace the
medium and type a carriage return to continue to the next
medium. Use only with the -o option. Using this option
with -o guarantees exclusive access to the character
special device or output file. Redirecting output to a
device or file does not guarantee exclusive access and
could result in a corrupted archive if a second process
opens the device or file while the first process is still
Interactively rename files. If the user types a carriage
return alone, the file is skipped. If the user types a
``.'' the original pathname will be retained. (Should be
used only with cpio -i.)
Reassign ownership and group information for each file to
user ID (ID must be a valid login ID from /etc/passwd).
This option is valid only for a privileged user.
Swap bytes within each half word.
Swap halfwords within each word.
Print a table of contents of the input. No files are
created (mutually exclusive with -V).
Truncate long file names to 14 characters. Use only with
the -i option.
Copy unconditionally (normally, an older file will not
replace a newer file with the same name).
Verbose: causes a list of file names to be printed. When
used with the -t option, the table of contents looks like
the output of an ls -l command (see ls(1)); dates are
displayed according to the locale specified in the LC_TIME
environment variable (see LANG on environ(5)).
Special Verbose: print a dot for each file read or
written. Useful to assure the user that cpio is working
without printing out all file names.
Process a UNIX System Sixth Edition archive format file.
Use only with the -i option (mutually exclusive with -c
NOTE: cpio assumes four-byte words.
If, when writing to a character device (-o) or reading from a
character device (-i), cpio reaches the end of a medium (such as
the end of a diskette), and the -O and -I options aren't used,
cpio will print the following message:
End of medium on input (output). To continue, type device/file name whe
To continue, you must replace the medium and type the character
special device name (/dev/rdsk/f0 for example) and press
<Return>. You may want to continue by directing cpio to use a
different device. For example, if you have two floppy drives you
may want to switch between them so cpio can proceed while you are
changing the floppies.
When standard input is directed through a pipe to cpio -o, files
are grouped so they can be redirected (>) to a single file
(../newfile). The -c option insures that the file will be
portable to other machines (as would the -H option). Instead of
ls(1), you could use find(1), echo(1), cat(1), and so on, to pipe
a list of names to cpio. You could redirect the output to a
device instead of a file.
ls | cpio -oc > ../newfile
cpio -i uses the output file of cpio -o (directed through a pipe
with cat in the example below), extracts those files that match
the patterns (memo/a1, memo/b * ), creates directories below the
current directory as needed (-d option), and places the files in
the appropriate directories. The -c option (with -k) is used if
the input file was created with a portable header. If no patterns
were given, all files from newfile would be placed in the
cat newfile | cpio -ickd "memo/a1" "memo/b * "
cpio -p takes the file names piped to it and copies or links (-l
option) those files to another directory (newdir in the example
below). The -d option allows you to create directories as needed.
The -m option lets you retain the modification time and security
level. (It is important to use the -depth option of find(1) to
generate pathnames for cpio. Use of this option eliminates
problems cpio could have in trying to create files under
read-only directories.) The destination directory, newdir, must
find . -depth -print | cpio -pdlmv newdir
Note that when you use cpio in conjunction with find, if you use
the -L option with cpio then you must use the -follow option with
find and vice versa. Otherwise there will be undesirable results.
file error (but cpio completes, displaying error number)
fatal error (cpio dies immediately)
Reading from magnetic tape in any fixed-length block length
besides the block length that the media was written in originally
will cause an I/O error. If you want to read a tape that was
written using a block-length besides the default of 512, you must
use the tapecntl(1) command ( qv ) to either set the block-length
of the drive to match the block length of the media or to set the
drive into variable block length mode.
language-specific message file. (See LANG on environ(5).)
ar(1), archives(4), cat(1), echo(1), find(1), ls(1), tar(1)
Support for large files
The cpio(1) utility supports the archival of files larger than 2
gigabytes (2GB) in size when using the ASCII (-c ) or CRC (-H
crc) formats. Files up to 2^63-1 bytes in size are supported.
Previous versions of cpio will not be able to extract files
larger than 2GB in size.
Restoring extended attributes
If you attempt to restore a cpio archive that contains extended
attribute information and the version of cpio being used does not
support one or more extended attributes found in the archive, the
The extended attributes not supported by the version of
cpio being used will not be restored. It is assumed that
if you use a version of cpio that does not support
extended attributes, the target file system probably does
not support extended attributes either.
cpio creates a file in /tmp with a name of the form
._xAtTr_n where n is an apparently arbitrary number. If
you use the -v option of cpio, the verbose output of cpio
will contain references to this file. This file, which is
not likely to be very large, can either be removed
manually or it will be removed with the other files in
/tmp during the next system reboot.
Compatibility with earlier releases
Versions of cpio on earlier releases of UnixWare used a slightly
different syntax for the -e option (that is, [-e extent_opt]). In
these earlier releases, the -e option applied only to Veritas
file system type (vxfs) extent attributes. For compatibility with
these earlier releases, if an action is specified with the -e
option, but without a preceding xattr_name=, that action is
assumed by cpio to apply to the vxfs_extent attribute only.
An archive created with the -c option on a System V Release 4
system cannot be read on System V Release 3.2 systems, or
earlier. Use the -H odc option, which is equivalent to the header
created by the -c option in earlier System V Releases, if the
cpio image will be read by a pre-System V Release 4 version of
In releases of UNIX System V prior to Release 4, symbolic links
are not understood. The result of copying in a symbolic link on
an older release will be a regular file that contains the
pathname of the referenced file.
Prior to Release 4, the default buffer size was 512 bytes.
Beginning with Release 4, the default buffer size is optimized
for the device and using the -C option to specify a different
block size may cause cpio to fail. Therefore, care must be taken
when choosing the block size. To avoid wasting space on streaming
tape drives, use the -C option and specify an appropriate block
Using variable-length block mode when writing magnetic tapes is
discouraged because it may not work correctly in releases before
SVR4.2 MP. Magnetic tape should always be written in fixed-length
block mode, even though you are free to change the default
fixed-block length from 512 bytes to any other fixed-block mode
the tape drive supports.
Pathnames are restricted to 256 characters for the binary (the
default) and -H odc header formats. Otherwise, pathnames are
restricted to 1024 characters.
Expanded fundamental types support
The default binary header format and the ODC header format do not
support expanded fundamental types (EFTs). Smaller, preSVR4-type
sizes are assumed by these header formats. If you are trying to
use cpio over file systems with EFT and one of these two header
formats are used, you will get the error message Old format
cannot support expanded types. Use the -c or the -Hcrc options
instead. See archives(4) for details on type sizes.
Copying block or character special files
Only a privileged user can copy block or character special files.
When attempting to redirect standard input or standard output
from or to a block or character special device you may get an
error message such as Cannot read from device or Cannot write to
device. The appearance of such a message does not necessarily
mean a true I/O error has occurred. It is more likely to mean the
user does not have access to that device; the user should ask the
system administrator to allocate the device for him or her.
It is not desirable for device overwriting to be the ordinary
behavior for cpio even when the -u option is specified. This has
been done for system resilience. If a device on an archive being
read in does not match a device that is already on the system, it
is almost always the case that the device on the archive is
different because the archive was exported from another system
that had different device numbers. To overwrite existing devices
in such a situation could be crippling to the system, depending
on which devices are overwritten and what the change is.
Blocks are reported in 512-byte quantities.
The st01 tape driver does not always require block sizes that are
in multiples of 512 bytes, but block size is device dependent.
Use tapecntl to set the tape driver to use the block size
supported by the tape device. Failure to set the block size
correctly will result in an error when the driver attempts to
write a block of the unsupported size.
Saving and restoring files with 000 permissions
If a file has ``000'' permissions and contains more than 0
characters of data, and the user does not have the appropriate
privilege, the file will not be saved or restored.
Matching tape block length on read
Reading from magnetic tape in any fixed-length block length,
besides the block length that the media was written in
originally, will cause an I/O error. In order to read a tape that
was written using some block length besides the default of 512,
use the tapecntl(1) command (qv) to either set the block length
of the drive to match the block length of the media, or to set
the drive into variable block length mode.
If POSIX2 is set in the current environment, then the
pattern-matching notation specified by POSIX.2 is used:
Matches any string, including the empty string.
Matches any single character.
[ . . . ]
Matches any one of the enclosed characters. A pair of
characters separated by `-' matches any symbol between the
pair (inclusive), as defined by the system default
collating sequence. If the first character following the
opening `[' is a `!', it is regarded as a not operator;
the characters within the braces are not used in the
In pattern, the special characters ``?'', ``*'' and ``['' also
match the / character. Multiple cases of pattern can be specified
and if no pattern is specified, ``*'' is used (that is, all files
(c) 2005 The SCO Group, Inc. All rights reserved.
SCO OpenServer Release 6.0.0 - 02 June 2005
See also cpio(1)
Man(1) output converted with