cpio(1) — Commands
NAME
cpio − Copies files to and from archive storage.
SYNOPSIS
cpio −o[aBcehvV] [−C value] [−M "string"] [−Odevice]
cpio −i[bBcdefmrsStuvz6] [−C value] [−M "string"] [−Idevice] [pattern ...]
cpio −p[adlmruvV] directory
STANDARDS
Interfaces documented on this reference page conform to industry standards as follows:
cpio: XPG4, XPG4−UNIX
Refer to the standards(5) reference page for more information about industry standards and associated tags.
FLAGS
A hyphen (−) is required before the −i, −I, −o, −O, and −p flags; all other flags follow −i, −o, or −p without leading spaces and without a hyphen.
[Digital] The following two flags are preceded by a hyphen and must be used separately from the other flags.
−Idevice[Digital] Specifies the input device containing the archive. This argument must be present to import data from a device.
−Odevice
[Digital] Specifies the output device to store the archive. This argument must be present to export data to a device.
Not all of the following flags can be used with each of the −o, −i, and −p flags.
aResets the access times of copied files to the current time. (When the l flag is also specified, the access times of the linked files are not reset.)
b[Digital] Swaps both bytes and halfwords. (See also the s and S flags.) If there is an odd number of bytes or halfwords in the file being processed, data can be lost. This flag can only be used with cpio −i.
BPerforms block input/output, 5120 bytes to a record. This flag cannot be used with cpio −p. It is meaningful only with data directed to or from /dev/rmt/∗. This flag does not work with certain magnetic tape drives. The C and B flags are mutually exclusive. If you specify both, the last one on the command line is used.
cWrites header information in ASCII character form. Specify this flag when POSIX compliance is required and when you are creating or restoring archives for or from another system.
C value[Digital] Performs block input/output using value as the record size. The C and B flags are mutually exclusive. If you specify both, the last one on the command line is used.
dCreates directories as needed.
e[Digital] Read or write cpio header information in extended cpio header format. Use this option to read or write block special or character special files. Any cpio archives created with the e option of DIGITAL UNIX Version 4.0 are not backward compatible with earlier versions of DIGITAL UNIX.
fCopies all files except those matching pattern (cpio −i only).
h[Digital] Forces cpio to follow symbolic links as if they were normal files or directories. The cpio command does not follow symbolic links, but instead saves the link text in the archive.
lLinks files rather than copying them, whenever possible. Symbolic (soft) links are created rather than hard links. This flag can be used only with cpio −p.
mRetains the previous file modification time. This flag cannot be used when copying directories.
M string[Digital] Specifies the End-of-Media message. This flag is used to customize the message that appears when it is time to change archive volumes. The −M flag is valid only when −I or −O is also specified.
rCauses cpio to ask whether or not to rename each file before copying it. If you do not want to change the file name, enter the current file name. You can press <Return> only to have cpio skip copying the file.
s[Digital] Swaps bytes. This flag can be used only with cpio −i. If there is an odd number of bytes in the file being processed, data can be lost.
S[Digital] Swaps halfwords. This flag can be used only with cpio −i. If there is an odd number of halfwords in the file being processed, data can be lost.
tCreates a table of contents of the input. This flag does not copy any files.
uCopies unconditionally. Otherwise, a file from the archive with the same name as an existing file in the file system is copied only if the archived file is the newer one.
vLists file names. If you use this flag with the t flag, the output looks similar to that of the ls −l command.
V[Digital] Prevents any extended attributes from being archived with associated files. This option is particularly useful for archiving files that are to be restored with previous versions of tar and cpio.
z[Digital] Positions the tape after the EOF marker on extraction or listing. The z option lets the user extract or list tapes that have multiple archives on them one after the other without error as a result of the tape not being positioned correctly for the next extraction or listing.
6[Digital] Processes an old file (one written in UNIX Sixth Edition format). This flag can be used only with cpio −i.
PARAMETERS
directoryA pathname of an existing directory to be used as the target of cpio -p.
patternExpressions making use of a pattern-matching notation similar to that used by the shell for file name 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.
In pattern, the special characters ?, ∗, and [ also match the / character.
Multiple cases of pattern can be specified and if no pattern is specified, the default for pattern is ∗ (that is, select all files).
DESCRIPTION
The cpio command copies files between archive storage and the file system. It is used to save and restore data from traditional format cpio archives.
There are three versions of the cpio command:
cpio −o (copy out)
This command reads file pathnames from standard input and copies these files to standard output along with pathnames and status information. Output is padded to a 512-byte boundary.
cpio −i (copy in)
This command reads from standard input an archive file created by the cpio −o command and copies from it the files with names that match pattern. These files are copied into the current directory tree. The file permissions are the same as the permissions associated with the files copied out using cpio −o. The owner and group of the files are those of the current user unless the user is superuser, in which case cpio retains the owner and group of the files of the previous cpio −o.
You can list more than one pattern using the file name notation described. The default pattern is ∗, selecting all files in the archive. In an expression such as [a-z], the hyphen means "through" according to the current collating sequence. The collating sequence is determined by the LC_COLLATE environment variable.
cpio −p (directory copy)
This command reads file pathnames from standard input and copies these files into the named directory. The specified directory must already exist. If these pathnames include directory names and if these directories do not already exist, you must use the −d flag to cause the directories to be created.
[Digital] Special files are not supported. Pathnames cannot exceed 128 bytes. Avoid giving cpio pathnames made up of many uniquely linked files because cpio might not have enough memory to keep track of them and could lose linking information.
ENVIRONMENT VARIABLES
The following environment variables affect the execution of cpio:
LANGProvides a default value for the internationalization variables that are unset or null. If LANG is unset or null, the corresponding value from the default locale is used. If any of the internationalization variables contain an invalid setting, the utility behaves as if none of the variables had been defined.
LC_ALLIf set to a non-empty string value, overrides the values of all the other internationalization variables.
LC_CTYPEDetermines the locale for the interpretation of sequences of bytes of text data as characters (for example, single-byte as opposed to multibyte characters in arguments and input files) and the behavior of character classes within bracketed file name patterns.
LC_MESSAGESDetermines the locale for the format and contents of diagnostic messages written to standard error.
LC_TIMEDetermines the format of date and time strings output when listing the contents of an archive with the -v flag.
NLSPATHDetermines the location of message catalogues for the processing of LC_MESSAGES.
TZDetermines the time zone used with date and time strings.
NOTES
[Digital] Archives created with extended attributes cannot be read by Version 2.0 of the cpio command. The following describes the results of restoring archived files and directories when you use Version 2.0 of the cpio command:
•[Digital] You cannot restore an archive directory with extended attributes. The extended attributes are restored as a regular file that cannot be overwritten; the original directory cannot be recreated. In addition, the cpio command restores the archived files containing extended attributes as regular files. When the cpio command restores the original file with the extended attributes, the command fails with errno:20.
•[Digital] You cannot archive files with extended attributes.
•[Digital] Archives created with the new pax utility and having cpio format, can be restored using only the new pax or cpio commands even if none of the archived files have extended attributes.
To achieve backward compatibility of archived files, use the following suggestions:
•Archive only files that do not have extended attributes.
•Use the old cpio command at /usr/opt/obsolete/usr/bin/cpio.
CAUTIONS
[Digital] When redirecting the output from cpio to a special file (device), redirect it to the raw device and not the block device. Because writing to a block device is done asynchronously, there is no way to know if the end of the device has been reached.
EXAMPLES
1.To copy files to magnetic tape, enter:
cpio −ov < file-list −O/dev/rmt12
This command copies the files with pathnames that are listed in the file specification in a compact form to the magnetic tape (/dev/rmt12). The −v flag causes cpio to display the name of each file as it is copied. This command is useful for making backup copies of files.
2.To copy files in the current directory whose names end with .c onto magnetic tape, enter:
ls ∗.c | cpio −ov −O/dev/rmt12
3.To copy the current directory and all subdirectories onto magnetic tape, enter:
find . −print | cpio −ov −O/dev/rmt12
This command saves the directory tree that starts with the current directory (.) and includes all of its subdirectories and files. Another way to do the same thing is by entering the following command:
find . −cpio /dev/rmt12 −print
The −print flag displays the name of each file as it is copied.
4.To list the files that have been saved onto a magnetic tape with cpio, enter:
cpio −itv −I/dev/rmt12
This command displays the table of contents of the data previously saved onto /dev/rmt12 in cpio format. To list only the file pathnames, use only the −it flags.
5.To copy the files previously saved with cpio from a magnetic tape, enter:
cpio −idmv −I/dev/rmt12
This command copies the files previously saved onto /dev/rmt12 by cpio back into the file system (specified by the −i flag). The −d flag lets cpio create the appropriate directories if a directory tree was saved. The −m flag maintains the last modification time that was in effect when the files were saved. The −v flag causes cpio to display the name of each file as it is copied.
6.To copy selected files from magnetic tape, enter:
cpio −i −I/dev/rmt12 "∗.c" "∗.o"
This command copies the files that end with .c or .o from magnetic tape. The patterns ∗.c and ∗.o must be enclosed in double quotation marks (" ") to prevent the shell from treating the ∗ (asterisk) as a pattern-matching character. In this special case, cpio itself decodes the pattern-matching characters.
7.To rename files as they are copied from magnetic tape, enter:
cpio −ir −I/dev/rmt12
The −r flag causes cpio to ask you whether or not to rename each file before copying it from magnetic tape. For example, the following message asks you whether you want to give the file saved as prog.c a new name as it is being copied:
Rename <prog.c>
To rename the file, type the new name and press <Return>. To keep the same name, you must enter the old name at the prompt. To avoid copying the file at all, press <Return> alone.
8.To copy a directory and all of its subdirectories, enter:
mkdir /u/jim/newdir
find . −print | cpio −pdl /u/jim/newdir
This command duplicates the current directory tree, including the current directory and all of its subdirectories and files. The duplicate is placed in the new /u/jim/newdir directory. The −l flag causes cpio to link files instead of copying them, when possible.
EXIT VALUES
The following exit values are returned:
0Successful completion
>0An error occurred
RELATED INFORMATION
Commands: ar(1), find(1), ls(1), ksh(1), pax(1), Bourne shell sh(1b), POSIX shell sh(1p), tar(1)