CPIO(1) SysV CPIO(1)
NAME
cpio - copy file archives in and out
SYNOPSIS
cpio -o[acBv]
cpio -i[BcdmrtuvfsSb6] [ patterns ]
cpio -p[adlmuv] directory
DESCRIPTION
cpio -o (copy out) reads the standard input to obtain a list of path
names and copies those files onto the standard output together with path
name and status information. Output is padded to a 512-byte boundary.
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 name-generating notation of sh(1). In patterns, meta-characters
?, *, and [...] match the slash / character. Multiple patterns may be
specified and if no patterns are specified, the default for patterns is *
(i.e., select all files). Each pattern should be surrounded by double
quotes. The extracted files are conditionally created and copied into
the current directory tree based upon the options described below. The
permissions of the files will be those of the previous cpio -o. The
owner and group of the files will be that of the current user unless the
user is super-user, which causes cpio to retain the owner and group of
the files of the previous cpio -o.
cpio -p (pass) reads the standard input to obtain a list of path names of
files that are conditionally created and copied into the destination
directory tree based upon the options described below.
cpio must be used with a mounted device. For example, when using cpio
with /dev/rct8, first issue the command:
mt -f /dev/rct8 rewind
Then proceed with the cpio command.
OPTIONS
a Resets access times of input files after they have been copied.
Access times are not reset for linked files when cpio -pla is
specified.
B Blocks input/output 5,120 bytes to the record. (Does not apply
to the pass option; meaningful only with data directed to or
from a character special device, e.g. /dev/rmt/0m.)
d Creates directories as needed.
c Writes header information in ASCII character form for
portability. Use this option when origin and destination
machines are different types.
r Interactively renames files. If you type a null line, the file
is skipped. (Not available with cpio -p.)
t Prints a table of contents of the input. No files are created.
u Copies 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)).
l Links files rather than copying them. Usable only with the -p
option.
m Retains previous file modification time. This option is
ineffective on directories that are being copied.
f Copies in all files except those in patterns.
s Swaps bytes within each half word. Use only with the -i
option.
S Swaps halfwords within each word. Use only with the -i option.
b Reverses the order of the bytes within each word. Use only
with the -i option.
6 Processes an old (i.e. UNIX System Sixth Edition format) file.
Only useful with -i (copy in).
NOTES
If cpio -i tries to create a file that already exists and the existing
file is the same age or newer, cpio will output a warning message and not
replace the file. (The -u option can be used to unconditionally
overwrite the existing file.)
cpio assumes four-byte words.
If cpio reaches end of medium (end of a diskette for example), when
writing to (-o) or reading from (-i) a character special device, cpio
will print the message:
If you want to go on, 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 carriage 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. (A
carriage return alone causes the cpio process to exit.)
Path names are restricted to 256 characters.
Only the super-user can copy special files.
Blocks are reported in 512-byte quantities.
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). Instead
of "ls," you could use find, echo, cat, etc. to pipe a list of names to
cpio. You could direct the output to a device instead of a file.
ls | cpio -o >../newfile
cpio -i uses the output file of cpio -o (directed through a pipe with cat
in the example), takes out 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. If no
patterns were given, all files from "newfile" would be placed in the
directory.
cat newfile | cpio -id memo/a1 memo/b*
cpio -p takes the file names piped to it and copies or links (-l option)
those files to another directory on your machine (newdir in the example).
The -d options says to create directories as needed. The -m option says
retain the modification time. (It is important to use the -depth option
of find to generate path names for cpio. This eliminates problems cpio
could have trying to create files under read-only directories.)
find . -depth -print | cpio -pdlmv newdir
BUGS
cpio supports multiple volumes. However, you must mount each additional
volume before proceeding. Since the window from which you have issued the
cpio command will be in a paused state (waiting for you to enter "go" or
"abort"), you must mount the tape device from another window, using the
mt command. For example, when using cpio with /dev/rct8, issue the
command:
mt -f /dev/rct8 rewind
Then you can proceed to the paused window, and issue "go".
SEE ALSO
ar(1), find(1), ls(1), tar(1).
cpio(4) in the SysV Programmer's Reference.