cpio(1) DG/UX 5.4 Rel. 2.01 cpio(1)
NAME
cpio - copy file archives in and out
SYNOPSIS
cpio -i[bBcdfkmrsStuvV6] [-C bufsize] [-E file] [-H hdr] [-I file [-M
message]] [-Q query-file] [-R ID] [pattern ...]
cpio -o[aABcLvV] [-C size] [-H hdr] [-O file [-M message]] [-Q
query-file]
cpio -p[adlLmuvVY] [-R ID]] directory
DESCRIPTION
The -i, -o, and -p options select the action to be performed. The
following list describes each of the actions (which are mutually
exclusive).
cpio -i (copy in) extracts files from the standard input, 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 *
(i.e., 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 is super-user. 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.)
cpio -o (copy out) reads the standard input to obtain a list of
pathnames and copies those files onto the standard output together
with pathname and status information. Output is padded to a 512-byte
boundary by default unless you supply the -B option (for a 5120-byte
block size) or the -C option (for a user-specified block size). You
will acheive an improvement in performance by using a block size that
is larger than the default.
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 below.
The meanings of the available options are
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-a Reset access times of input files after they have been copied.
Access times are not reset for linked files when cpio -pla is
specified (mutually exclusive with -m).
-A 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.
-b Reverse the order of the bytes within each word. (Use only
with the -i option.)
-B Input/output is to be blocked 5120 bytes to the record. The
default buffer size is 512 bytes when this and the -C options
are not used. If you use the larger block size, the operation
takes far less time. The smaller block size is desirable only
when you are dumping data that you may need on a system whose
cpio command requires that data be in 512-byte blocks. (You
cannot use the -B option with the pass option; -B is
meaningful only with data directed to or from a character
special device, for example, /dev/rmt/0.)
-c Read or write header information in ASCII character form for
portability. The output of cpio -oc complies with the
extended cpio format described in POSIX and XPG3. Always use
this option (or the -H option) when the origin and the
destination machines are different types (mutually exclusive
with -H and -6).
-C bufsize
Input/output is to be blocked bufsize bytes to the record,
where bufsize is replaced by a positive integer. The default
buffer size is 512 bytes when this and -B options are not
used. (-C does not apply to the pass option; -C is meaningful
only with data directed to or from a character special device,
e.g. /dev/rmt/0.) Some types of tape drives, including models
6577 (QIC-150 150MB 1/4" cartridge) and 6590 (8mm 2GB helical
scan) require that bufsize be a multiple of 512.
-d Directories are to be created as needed.
-E file
Specify an input file (file) that contains a list of filenames
to be extracted from the archive (one filename per line).
-f Copy in all files except those in patterns. (See the paragraph
on cpio -i for a description of patterns.)
-H hdr 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 device numbers and an
additional per-file checksum
ustar or USTAR - IEEE/P1003 Data Interchange Standard header
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and format
tar or TAR - tar header and format
odc - ASCII header with small device numbers (the same as -c).
asc - the new "portable" format. This format is produced by
the -c option on some other System V.4 systems.
-I file
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.
-k 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.
-l Whenever possible, link files rather than copying them.
(Usable only with the -p option.)
-L Follow symbolic links. The default is not to follow symbolic
links.
-m Retain previous file modification time. This option is
ineffective on directories that are being copied (mutually
exclusive with -a).
-M message
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.
-O file
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.
-Q query-file
Specify query-file as the file from which to read input from
the operator. Normally, cpio writes operator messages to
stderr and reads operator responses from /dev/tty. This
option allows operator input to be read from an alternate
source such as fifo-special file. This is very useful when
running cpio from cron(1M) since cron jobs have no controlling
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tty. For example,
find /foo -print | cpio -o -Q /tmp/fifo >/dev/rmt/0 2>/dev/console
would backup directory foo to tape /dev/rmt/0. Error messages
and operator queries would be written to the console, and
operator input would be read from the fifo file /tmp/fifo.
Running this command from a cron job would allow you to send
cpio output to the console without having to take control of
the console for input. Operator queries from cpio (such as
requests for the next tape) could be answered by echoing
responses to /tmp/fifo.
-r 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. (Not available with
cpio -p.)
-R ID 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 the super-user.
-s Swap bytes within each half word.
-S Swap halfwords within each word.
-t Print a table of contents of the input. No files are created
(mutually exclusive with -V).
-u Copy unconditionally (normally, an older file will not replace
a newer file with the same name).
-v 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)].
-V 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.
-Y Create symbolic links instead of copying files. (This option
can only be used with the -p option).
-6 Process a UNIX System Sixth Edition archive format file. Use
only with the -i option (mutually exclusive with -c and -H)).
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 and the -O
and -I options aren't used, cpio will print the following message:
If you want to go on, type device/file name when ready.
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To continue, you must replace the medium and type the character
special device name (/dev/rmt/0 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.
(Simply pressing RETURN causes the cpio process to exit.)
EXAMPLES
The following examples show three uses of cpio.
When standard input is directed through a pipe to cpio -o, it groups
the files so they can be directed (>) 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 direct 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 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 directory.
cat newfile | cpio -icd "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 says to create directories as needed. The -m
option says retain the modification time. (It is important to use
the -depth option of find(1) to generate pathnames for cpio. This
eliminates problems cpio could have trying to create files under
read-only directories.) The destination directory, newdir, must
exist.
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.
SEE ALSO
ar(1), cat(1), echo(1), find(1), ls(1), tar(1), ar(4).
NOTES
An archive created with the -Hasc option on a Release 5.4 DG/UX
system cannot be read on a DG/UX Release 4.3 system.
DG/UX System releases prior to Release 5.4 do not understand symbolic
links. The result of copying in a symbolic link on an older release
will be a regular file that contains the pathname of the referenced
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file.
Pathnames are restricted to 256 characters for the binary (the
default) and
-H odc header formats. Otherwise, pathnames are restricted to 1024
characters.
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 will not be saved or
restored.
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