cpio Command

Purpose

Copies files into and out of archive storage and directories. This document describes the AIX® cpio command and the System V cpio command.

Syntax

cpio -o [  a ] [  c ] [ -E{force|ignore|warn} ] [-g] [ -H hdr][ -U ] [  v ] [  B | C Value ] [ -Z ] <FileName >Output

cpio -i [  b ] [  c ] [  d ] [ -E{force|ignore|warn} ] [ f ] [ -H hdr] [  m ] [ M ] [ r ] [ s ] [ t ] [ -U ] [  u ] [ v ] [  S ] [ 6 ] [  B | C Value ] [ -Z ] [  Pattern... ] <Input

cpio -p [  a ] [  d ] [ -E{force|ignore|warn} ] [  l ] [  m ] [  M ] [ -U ] [  u ] [  v ] [ -Z ] Directory <FileName

Description

cpio -o Command

The cpio -o command reads file path names from standard input and copies these files to standard output, along with path names and status information. Avoid giving the cpio command path names made up of many uniquely linked files, as it may not have enough memory to keep track of them and would lose linking information.

cpio -i Command

The cpio -i command reads from standard input an archive file created by the cpio -o command and copies from it the files with names that match the Pattern parameter. These files are copied into the current directory tree. You can list more than one Pattern parameter, using the file name notation described in the ksh command. Note that in this application the special characters * (asterisk), ? (question mark), and [...] (brackets and ellipses) match the / (slash) in path names, in addition to their use as described in the ksh command. The default for the Pattern parameter is an * (asterisk), selecting all files in the Input. In an expression such as [a-z], the minus sign means through according to the current collating sequence.

A collating sequence can define equivalence classes for use in character ranges.

cpio -p Command

cpio -U command

For AIX 5.3, the cpio command will ignore extended attributes by default. The -U option informs cpio to archive or restore attributes, which includes ACLs.

A new record type is required for extended attribute entries in cpio archive files. A new record type is also required for ACL entries in cpio archive files.

Each object in the cpio archive contains a cpio header followed by the data for the specified object.

Parameters

Flags

All flags must be listed together, without any blanks between them. Not all of the following flags can be used with each of the -o, -i, and -p flags.

Exit Status

This command returns the following exit values:

Security

Attention RBAC users and Trusted AIX users: This command can perform privileged operations. Only privileged users can run privileged operations. For more information about authorizations and privileges, see Privileged Command Database in Security. For a list of privileges and the authorizations associated with this command, see the lssecattr command or the getcmdattr subcommand.

Examples

1. To copy files onto diskette, enter:

   cpio -ov <filenames >/dev/rfd0

   This copies the files with path names listed in the filenames file in a compact form onto the diskette (>/dev/rfd0). The v flag causes the cpio command to display the name of each file as it is copied. This command is useful for making backup copies of files. The diskette must already be formatted, but it must not contain a file system or be mounted.

   Note: Files with uid's and gid's greater than 65535 cannot be archived using the cpio command. In such instances, the user should use backup and restore.

2. To copy files in the current directory onto diskette, enter:

   ls *.c | cpio -ov >/dev/rfd0

   This copies all the files in the current directory whose names end with .c
3. To copy the current directory and all subdirectories onto diskette, enter:

   find . -print | cpio -ov >/dev/rfd0

   This saves the directory tree that starts with the current directory (.) and includes all of its subdirectories and files. Do this faster by entering:

   find . -cpio /dev/rfd0 -print

   The -print entry displays the name of each file as it is copied.
4. To list the files that have been saved onto a diskette with the cpio command, enter:

   cpio -itv </dev/rfd0

   This displays the table of contents of the data previously saved onto the /dev/rfd0 file in the cpio command format. The listing is similar to the long directory listing produced by the ls -l command. To list only the file path names, use only the -it flags.
5. To copy the files previously saved with the cpio command from a diskette, enter:

   cpio -idmv </dev/rfd0

   This copies the files previously saved onto the /dev/rfd0 file by the cpio command back into the file system (specify the -i flag). The d flag allows the cpio command to create the appropriate directories if a directory tree is saved. The m flag maintains the last modification time in effect when the files are saved. The v flag causes the cpio command to display the name of each file as it is copied.
6. To copy selected files from diskette, enter:
   cpio -i "*.c" "*.o" </dev/rfd0
   This copies the files that end with .c or .o from diskette. Note that the patterns "*.c" and "*.o" must be enclosed in quotation marks to prevent the shell from treating the * (asterisk) as a pattern-matching character. This is a special case in which the cpio command itself decodes the pattern-matching characters.
7. To rename files as they are copied from diskette, enter:

   cpio -ir </dev/rfd0

   The -r flag causes the cpio command to ask you whether to rename each file before copying it from diskette. For example, the message:

   Rename <prog.c>

   asks whether to give the file saved as prog.c a new name as it is copied. To rename the file, type the new name and press the Enter key. To keep the same name, you must enter the name again. To avoid copying the file at all, press the Enter key.
8. To copy a directory and all of its subdirectories, enter:

   mkdir /home/jim/newdir
   find . -print | cpio -pdl /home/jim/newdir

   This duplicates the current directory tree, including the current directory and all of its subdirectories and files. The duplicate is placed in the new /home/jim/newdir directory. The l flag causes the cpio command to link files instead of copying them, when possible.

   Note: The performance of cpio to the 9348 Magnetic Tape Unit Model 12 can be improved by changing the default block size. To change the block size, enter the following at the command line:

   chdev -1 <device_name> -a block_size=32k

9. To copy files in the current directory onto diskette and preserve the ACL and EA associated with the files, enter:

   ls *.c | cpio -oUv >/dev/rfd0
   

Files

System V cpio Command

Purpose (System V cpio Command)

Copies files into and out of archive storage and directories.

Syntax (System V cpio Command)

cpio -i [ -b ] [ -B ] [ -c ] [ -d ] [ -f ] [ -k ] [ -m ] [ -r ] [ -s ] [ -S ] [ -T ] [ -t ] [ -u ] [ -v ] [ -V ] [ –6 ] [ -C bufsize ] [ -E file ] [ -H hdr ] [ -I file [ -M message ] ] [ -R ID ] ] [ Patterns ...]

cpio -o [ -a ] [ -A ] [ -B ] [ -c ] [ -L ] [ -v ] [ -V ] [ -C bufsize ] [ -H hdr ] [ -K mediasize ] [ -O file [ -M message ] ]

cpio -p [ -a ] [ -d ] [ -l ] [ -L ] [ -m ] [ -u ] [ -v ] [ -V ] [ -R ID ] Directory

Description (System V cpio Command)

The cpio command copies files into and out of an archive. The -i, -o and -p options select the action to be performed. The following list describes each of the actions. The -o, -p and -i options are mutually exclusive.

cpio -i (copy in)

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 ksh. 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 either a, b or c.) 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 cpio -i command reads the standard input of an archive file created that was using the cpio -o command, and copies the files with names that match the pattern parameter. The pattern parameter is a regular expression given with general notation of ksh. These files are copied into the current directory tree. More than one pattern parameter can be used, using the file name notation described in the ksh command. The patterns can be special characters * (asterisk), ? (question mark), and [...] (brackets and ellipses). The default for the pattern parameter is an * (asterisk), selecting all files in the input. In an expression such as [a-z], the minus sign means through according to the current collating sequence.

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 the root user. If this is true, owner and group permissions will be the same as those resulting from the previous cpio -o. Blocks are reported in 512-byte quantities.

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. On the other hand if the file being extracted is older than the one in the cpio archive then the existing file will be replaced without any warning from the command.

cpio -o (copy out)

cpio -o 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.

cpio -p (copy pass)

cpio -p reads the standard input to obtain a list of path names of files and copies these files into the directory named by the Directory parameter. The specified directory must already exist. If these path names include directory names that do not already exist, you must use the d flag to cause the specified directory to be created. By default the Access Control List's (ACL) are transferred [copied] from source file to destination file with this option only.

Flags (System V cpio Command)

Parameters (System V cpio Command)

Exit Status (System V cpio Command)

0

The command completed successfully.

>0

An error occurred.

Examples (System V cpio Command)

1. To copy all the files in the current directory onto tape device /dev/rmt0, enter:

   find . | /usr/sysv/bin/cpio -oc >/dev/rmt0

   The -c option ensures that the file is made portable to other machines. Instead of find you can also use ls, cat, echo and so on to pipe a list of names to cpio. The output could also be redirected to a regular cpio file instead of a device.
2. To extract an cpio archive file named "arfile" created by cpio command use the following:

   /usr/sysv/bin/cpio -icdI arfile 

   Here all the files are extracted from the cpio archive and the -d option ensures that the required directory paths are created as when required.
3. A cpio archive file can also be extracted as follows:

   /usr/sysv/bin/cpio -icd < arfile 

   The -d option ensures that all the required directories are created under the current directory. The standard input can be used only if -I flag is not specified.
4. To extract unconditionally all the files in "arfile" use the following:

   /usr/sysv/bin/cpio -icduI arfile 

5. To skip any files which corrupted headers, cpio can be used as follows:

   /usr/sysv/bin/cpio -ickudI arfile 

6. If the access time of the files archived needs to be reset when cpio is used to create an archive, use cpio in the following way:

   ls | /usr/sysv/bin/cpio -oca > arfile 

7. To extract only the files matching the pattern "a*" from the archive "ar", use the following:

   cat ar | /usr/sysv/bin/cpio -ickud "a*"

   This command extracts all the files starting with letter "a".
8. To display the list of files archived, use cpio in the following way:

   cat ar | /usr/sysv/bin/cpio -itv

   The verbose option (-v) ensures that the list given by -t option is listed in a very similar way as ls -l command.
9. The cpio -p command can be used to copy a directory tree to a new path, as follows:

   find . -print | /usr/sysv/bin/cpio -pd /home/user1/newdir 

   The entire directory tree from current directory is copied to /home/user1/newdir. The -d option ensures that directories are created as necessary.
10. To retain the modification time and access control list while copying the directory tree, use the cpio command as follows:

    find . -name "*.o" -print | /usr/sysv/bin/cpio -pdlmv /home/user1/newdir 

    In this example only the .o files under the directory tree are copied to /home/user1/newdir.
11. To append a list of files to a cpio archive matching a particular pattern, invoke a command similar to the following:

    ls d* | /usr/sysv/bin/cpio -oAO /tmp/ar 

    In this example, all files starting with "d" in the current directory will be appended to the cpio archive.
12. To extract only a list of files listed inside a regular file from an cpio archive, use the following command:

    cat ar | /usr/sysv/bin/cpio -i -E Efile 

    In this example, cpio extracts only those files that are listed in the regular file "Efile", provided the specified file name exists in the archive.
13. To hard link all the files instead of copying them, invoke a command similar to the following:

    ls d* | /usr/sysv/bin/cpio -pdl /home/user2/newdir 

    In this example, the -l flag ensures all the file names starting with the character "d" are hard linked to the /home/user2/newdir, the directory specified. Hard linking across file systems is not allowed, thus the -l option cannot be used when the destination directory is in any other filesystem.

Files (System V cpio Command)