cpio(1) User Commands cpio(1)NAMEcpio - copy file archives in and out
SYNOPSIScpio-i [-bBcdfkmPrsStuvV6@/] [-C bufsize] [-E file]
[-H header] [-I [-M message]] [-R id] [pattern]...
cpio-o [-aABcLPvV@/] [-C bufsize] [-H header]
[-O file [-M message]]
cpio-p [-adlLmPuvV@/] [-R id] directory
DESCRIPTION
The cpio command copies files into and out of a cpio archive. The cpio
archive can span multiple volumes. The -i, -o, and -p options select
the action to be performed. The following list describes each of the
actions. These actions are mutually exclusive.
Copy In Mode
cpio-i (copy in) extracts files from the standard input, which is
assumed to be the product of a previous cpio-o command. Only files
with names that match one of the patterns are selected. See sh(1) and
OPERANDS for more information about pattern. Extracted files are condi‐
tionally copied into the current directory tree, based on the options
described below. The permissions of the files are those of the previous
cpio-o command. The owner and group are the same as the current user,
unless the current user has the {PRIV_FILE_CHOWN_SELF} privilege. See
chown(2). If this is the case, owner and group are the same as those
resulting from the previous cpio-o command. Notice that if cpio-i
tries to create a file that already exists and the existing file is the
same age or younger (newer), cpio outputs a warning message and not
replace the file. The -u option can be used to unconditionally over‐
write the existing file.
Copy Out Mode
cpio-o (copy out) reads a list of file path names from the standard
input and copies those files to the standard output, together with path
name and status information in the form of a cpio archive. Output is
padded to an 8192-byte boundary by default or to the user-specified
block size (with the -B or -C options) or to some device-dependent
block size where necessary (as with the CTC tape).
Pass Mode
cpio-p (pass) reads a list of file path names from the standard input
and conditionally copies those files into the destination directory
tree, based on the options described below.
If the underlying file system of the source file supports detection of
holes as reported by pathconf(2), the file is a sparse file, and the
destination file is seekable, then holes in sparse files are preserved
in pass mode, otherwise holes are filled with zeros.
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 are not used, cpio prints the fol‐
lowing message:
To continue, type device/file name when ready.
To continue, you must replace the medium and type the character special
device name (/dev/rdiskette for example) and press RETURN. You might
want to continue by directing cpio to use a different device. For exam‐
ple, if you have two floppy drives you might want to switch between
them so cpio can proceed while you are changing the floppies. Press
RETURN to cause the cpio process to exit.
OPTIONS
The following options are supported:
-i (copy in) Reads an archive from the standard input and condition‐
ally extracts the files contained in it and places them into the
current directory tree.
-o (copy out) Reads a list of file path names from the standard
input and copies those files to the standard output in the form
of a cpio archive.
-p (pass) Reads a list of file path names from the standard input
and conditionally copies those files into the destination direc‐
tory tree.
The following options can be appended in any sequence to the -i, -o, or
-p options:
-a Resets access times of input files after they have been
copied, making cpio's access invisible. Access times are
not reset for linked files when cpio-pla is specified.
-A Appends 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. The
effect on files that are linked in the existing portion
of the archive is unpredictable.
-b Reverses the order of the bytes within each word. Use
only with the -i option.
-B Blocks input/output 5120 bytes to the record. The default
buffer size is 8192 bytes when this and the -C options
are not used. -B does not apply to the -p (pass) option.
-c Reads or writes header information in ASCII character
form for portability. There are no UID or GID restric‐
tions associated with this header format. Use this option
between SVR4-based machines, or the -H odc option between
unknown machines. The -c option implies the use of
expanded device numbers, which are only supported on
SVR4-based systems. When transferring files between SunOS
4 or Interactive UNIX and the Solaris 2.6 Operating envi‐
ronment or compatible versions, use -H odc.
-C bufsize Blocks input/output bufsize bytes to the record, where
bufsize is replaced by a positive integer. The default
buffer size is 8192 bytes when this and -B options are
not used. -C does not apply to the -p (pass) option.
-d Creates directories as needed.
-E file Specifies an input file (file) that contains a list of
filenames to be extracted from the archive (one filename
per line).
-f Copies in all files except those in patterns. See OPER‐
ANDS for a description of pattern.
-H header Reads or writes header information in header format.
Always use this option or the -c option when the origin
and the destination machines are different types. This
option is mutually exclusive with options -c and -6.
Valid values for header are:
bar bar head and format. Used only with the
-i option ( read only).
crc | CRC ASCII header with expanded device num‐
bers and an additional per-file check‐
sum. There are no UID or GID restric‐
tions associated with this header for‐
mat.
odc ASCII header with small device numbers.
This is the IEEE/P1003 Data Interchange
Standard cpio header and format. It has
the widest range of portability of any
of the header formats. It is the offi‐
cial format for transferring files
between POSIX-conforming systems (see
standards(5)). Use this format to commu‐
nicate with SunOS 4 and Interactive
UNIX. This header format allows UIDs and
GIDs up to 262143 to be stored in the
header.
tar | TAR tar header and format. This is an older
tar header format that allows UIDs and
GIDs up to 2097151 to be stored in the
header. It is provided for the reading
of legacy archives only, that is, in
conjunction with option -i.
Specifying this archive format with
option -o has the same effect as speci‐
fying the "ustar" format: the output ar‐
chive is in ustar format, and must be
read using -H ustar.
ustar | USTAR IEEE/P1003 Data Interchange Standard tar
header and format. This header format
allows UIDs and GIDs up to 2097151 to be
stored in the header.
Files with UIDs and GIDs greater than the limit stated
above are archived with the UID and GID of 60001. To
transfer a large file (8 Gb — 1 byte), the header format
can be tar|TAR, ustar|USTAR, or odc only.
-I file Reads the contents of file as an input archive, instead
of the standard input. 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.
-k Attempts to skip corrupted file headers and I/O errors
that might 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 can terminate prematurely.
cpio finds the next good header, which can be one for a
smaller archive, and terminate when the smaller archive's
trailer is encountered. Use only with the -i option.
-l In pass mode, makes hard links between the source and
destination whenever possible. If the -L option is also
specified, the hard link is to the file referred to by
the symbolic link. Otherwise, the hard link is to the
symbolic link itself. Use only with the -p option.
-L Follows symbolic links. If a symbolic link to a directory
is encountered, archives the directory referred to by the
link, using the name of the link. Otherwise, archives the
file referred to by the link, using the name of the link.
-m Retains previous file modification time. This option is
ineffective on directories that are being copied.
-M message Defines 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.
-O file Directs the output of cpio to file, instead of the stan‐
dard output. 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.
-P Preserves ACLs. If the option is used for output, exist‐
ing ACLs are written along with other attributes, except
for extended attributes, to the standard output. ACLs are
created as special files with a special file type. If the
option is used for input, existing ACLs are extracted
along with other attributes from standard input. The
option recognizes the special file type. Notice that
errors occurs if a cpio archive with ACLs is extracted by
previous versions of cpio. This option should not be used
with the -c option, as ACL support might not be present
on all systems, and hence is not portable. Use ASCII
headers for portability.
-r Interactively renames files. If the user types a carriage
return alone, the file is skipped. If the user types a
``.'', the original pathname is retained. Not available
with cpio-p.
-R id Reassigns ownership and group information for each file
to user ID. (ID must be a valid login ID from the passwd
database.) This option is valid only when id is the
invoking user or the super-user. See NOTES.
-s Swaps bytes within each half word.
-S Swaps halfwords within each word.
-t Prints a table of contents of the input. If any file in
the table of contents has extended attributes, these are
also listed. No files are created. -t and -V are mutually
exclusive.
-u Copies unconditionally. Normally, an older file is not
replaced a newer file with the same name, although an
older directory updates a newer directory.
-v Verbose. Prints a list of file and extended attribute
names. When used with the -t option, the table of con‐
tents looks like the output of an ls -l command (see
ls(1)).
-V Special verbose. Prints a dot for each file read or writ‐
ten. Useful to assure the user that cpio is working with‐
out printing out all file names.
-6 Processes a UNIX System Sixth Edition archive format
file. Use only with the -i option. This option is mutu‐
ally exclusive with -c and -H.
-@ Includes extended attributes in archive. By default, cpio
does not place extended attributes in the archive. With
this flag, cpio looks for extended attributes on the
files to be placed in the archive and add them, as regu‐
lar files, to the archive. The extended attribute files
go in the archive as special files with special file
types. When the -@ flag is used with -i or -p, it
instructs cpio to restore extended attribute data along
with the normal file data. Extended attribute files can
only be extracted from an archive as part of a normal
file extract. Attempts to explicitly extract attribute
records are ignored.
-/ Includes extended system attributes in archive. By
default, cpio does not place extended system attributes
in the archive. With this flag, cpio looks for extended
system attributes on the files to be placed in the ar‐
chive and add them, as regular files, to the archive. The
extended attribute files go in the archive as special
files with special file types. When the -/ flag is used
with -i or -p, it instructs cpio to restore extended sys‐
tem attribute data along with the normal file data.
Extended system attribute files can only be extracted
from an archive as part of a normal file extract.
Attempts to explicitly extract attribute records are
ignored.
OPERANDS
The following operands are supported:
directory A path name of an existing directory to be used as the
target of cpio-p.
pattern Expressions making use of a pattern-matching notation sim‐
ilar to that used by the shell (see sh(1)) for filename
pattern matching, and similar to regular expressions. The
following metacharacters are defined:
* 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
`!', the results are unspecified.
! The ! (exclamation point) means not. For example,
the !abc* pattern would exclude all files that
begin with abc.
In pattern, metacharacters ?, *, and [...] match the slash
(/) character, and backslash (\) is an escape character.
Multiple cases of pattern can be specified and if no pat‐
tern is specified, the default for pattern 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.
USAGE
See largefile(5) for the description of the behavior of cpio when
encountering files greater than or equal to 2 Gbyte ( 2^31 bytes).
EXAMPLES
The following examples show three uses of cpio.
Example 1 Using standard input
example% ls | cpio-oc > ../newfile
When standard input is directed through a pipe to cpio-o, as in the
example above, it groups the files so they can be directed (>) to a
single file (../newfile). The -c option insures that the file is porta‐
ble 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 direct the output to a device instead of a file.
Example 2 Extracting files into directories
example% cat newfile | cpio-icd "memo/a1" "memo/b*"
In this example, cpio-i uses the output file of cpio-o (directed
through a pipe with cat), 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 directo‐
ries. The -c option is used if the input file was created with a porta‐
ble header. If no patterns were given, all files from newfile would be
placed in the directory.
Example 3 Copying or linking files to another directory
example% find . -depth -print | cpio-pdlmv newdir
In this example, cpio-p takes the file names piped to it and copies or
links (-l option) those files to another directory, newdir. The -d
option says to create directories as needed. The -m option says to
retain the modification time. (It is important to use the -depth option
of find(1) to generate path names for cpio. This eliminates problems
that cpio could have trying to create files under read-only directo‐
ries.) The destination directory, newdir, must exist.
Notice that when you use cpio in conjunction with find, if you use the
-L option with cpio, you must use the -follow option with find and vice
versa. Otherwise, there are undesirable results.
For multi-reel archives, dismount the old volume, mount the new one,
and continue to the next tape by typing the name of the next device
(probably the same as the first reel). To stop, type a RETURN and cpio
ends.
ENVIRONMENT VARIABLES
See environ(5) for descriptions of the following environment variables
that affect the execution of cpio: LC_COLLATE, LC_CTYPE, LC_MESSAGES,
LC_TIME, TZ, and NLSPATH.
TMPDIR cpio creates its temporary file in /var/tmp by default. Oth‐
erwise, it uses the directory specified by TMPDIR.
EXIT STATUS
The following exit values are returned:
0 Successful completion.
>0 An error occurred.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
┌─────────────────────────────┬─────────────────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├─────────────────────────────┼─────────────────────────────┤
│Availability │SUNWcs │
├─────────────────────────────┼─────────────────────────────┤
│CSI │Enabled │
├─────────────────────────────┼─────────────────────────────┤
│Interface Stability │Committed │
└─────────────────────────────┴─────────────────────────────┘
SEE ALSOar(1), cat(1), echo(1), find(1), ls(1), pax(1), setfacl(1), sh(1),
tar(1), chown(2), archives.h(3HEAD), attributes(5), environ(5),
fsattr(5), largefile(5), standards(5)NOTES
The maximum path name length allowed in a cpio archive is determined by
the header type involved. The following table shows the proper value
for each supported archive header type.
Header type Command line options Maximum path name length
BINARY "-o" 256
POSIX "-oH odc" 256
ASCII "-oc" 1023
CRC "-oH crc" 1023
USTAR "-oH ustar" 255
When the command line options "-o -H tar" are specified, the archive
created is of type USTAR. This means that it is an error to read this
same archive using the command line options "-i -H tar". The archive
should be read using the command line options "-i -H ustar". The
options "-i -H tar" refer to an older tar archive format.
An error message is output for files whose UID or GID are too large to
fit in the selected header format. Use -H crc or -c to create archives
that allow all UID or GID values.
Only the super-user can copy special files.
Blocks are reported in 512-byte quantities.
If a file has 000 permissions, contains more than 0 characters of data,
and the user is not root, the file is not saved or restored.
When cpio is invoked in Copy In or Pass Mode by a user with
{PRIV_FILE_CHOWN_SELF} privilege, and in particular on a system where
{_POSIX_CHOWN_RESTRICTED} is not in effect (effectively granting this
privilege to all users where not overridden), extracted or copied files
can end up with owners and groups determined by those of the original
archived files, which can differ from the invoking user's. This might
not be what the user intended. The -R option can be used to retain file
ownership, if desired, if you specify the user's id.
The inode number stored in the header (/usr/include/archives.h) is an
unsigned short, which is 2 bytes. This limits the range of inode num‐
bers from 0 to 65535. Files which are hard linked must fall in this
inode range. This could be a problem when moving cpio archives between
different vendors' machines.
You must use the same blocking factor when you retrieve or copy files
from the tape to the hard disk as you did when you copied files from
the hard disk to the tape. Therefore, you must specify the -B or -C
option.
During -p and -o processing, cpio buffers the file list presented on
stdin in a temporary file.
The new pax(1) format, with a command that supports it (for example,
tar), should be used for large files. The cpio command is no longer
part of the current POSIX standard and is deprecated in favor of pax.
SunOS 5.11 3 Aug 2009 cpio(1)