scpio - Man Page

scpio [ other options ] -o[aBcv]
scpio [ other options ] -i[Bcdmruvf] [ pattern ... ]
scpio [ other options ] -it[Bcvf] [ pattern ... ]
scpio [ other options ] -p[adlmuv] directory

The scpio utility, depending on the options used:

• copies files to an archive file
• extracts files from an archive file
• lists files from an archive file
• copies files from one directory tree to another.

The scpio utility supports the XBD specification Utility Syntax Guidelines. The cpio standard does not allow the option modifiers to be presented as separate arguments from the option letters. The scpio implementation allows option modifiers to be presented as separate arguments from the option letters. When writing portable shell scripts do never make use of this feature.

The following options are supported:

-o

(Copy Out.) Read the standard input to obtain a list of pathnames and copy those files onto the standard output together with pathname and status information. Output is padded to a 512-byte boundary.

-i

(Copy In.) Extract files from the standard input, which is assumed to be the product of a previous scpio -o. Only files with names that match patterns are selected. 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 scpio -o. The owner and group of the files will be that of the current user unless the user has appropriate privileges, which causes scpio to retain the owner and group of the files of the previous scpio -o. If the archive being read does not match the modifier specified, scpio may consider this to be an error and exit or may recognise the archive and continue processing. Only a user with appropriate privileges can extract block special or character special files from an archive.

-it

(List.) List files from the archive. This is a sub mode of the copy in mode, no files are created in list mode.

-p

(Pass.) Read the standard input to obtain a list of pathnames of files that are conditionally created and copied into the destination directory tree based upon the option modifiers described below.

The following option modifiers can be appended in any sequence to the -o, -i or -p options:

a

Reset access times of input files after they have been copied. (When option l (see below) is also specified, the access times of the linked files are not reset.)

B

Block input/output 5120 bytes to the record (does not apply to the -p option; meaningful only with data directed to or from character special files).

d

Create directories as needed.

c

Write or read header information in character form for portability. Note that the Open Group standard does not specify the archive format that should be used with the c option. For this reason it is questionable wether the c option increases portability in general.

The archive format used by scpio with the c option is the format from the -H asc option. It gives best cpio compatibility when transferring files to SVR4-based systems (except that the file size is limited to 2 gigabytes). When transferring files in cpio archives to unknown operating systems, it is unwise to use the c option.

r

Interactively rename files. For each archive member matching pattern operand, a prompt will be written to the file /dev/tty. The prompt will contain the name of the archive member, but the format is otherwise unspecified. A line will then be read from /dev/tty. If this line is blank, the archive member will be skipped. If this line consists of a single period, the archive member will be processed with no modification to its name. Otherwise, its name will be replaced with the contents of the line. The scpio utility will immediately exit with a non-zero exit status if end-of-file is encountered when reading a response, or if /dev/tty cannot be opened for reading and writing.

t

Write a table of contents of the input. No files are created.

u

Copy unconditionally (normally, an older file will not replace a newer file with the same name).

v

Verbose: print the names of the affected files. With the t option, provides a detailed listing.

l

Whenever possible, link files rather than copying them. Usable only with the -p option. The l option modifier is not yet supported by scpio.

m

Retain previous file modification time. This option is ineffective on directories that are being copied.

f

Copy in all files except those in patterns.

The following other options are implemented as SVr4 compliant extension to the Open Group standard:

-6

Extract UNIX System Sixth Edition cpio archives. This option is not valid in archive create mode, it is mutually exclusive with -c, -H, and artype=. As is is unclear how UNIX System Sixth Edition cpio archives look like, this option is currently unsupported.

-@

Include extended file attributes in the archive. This option is currently unsupported.

-A

Append files to an existing archive. The -A option only works together with the -O option. See star -r for more information.

-b

Reverses the order of the bytes within each word. It is unclear what a word is supposed to be. This option is unsupported but not needed as scpio includes automatic byte order recognition.

-C #

Sets (input/output) archive block size to # bytes.

-E name

Read filenames for store/create/list command from name. The file name must contain a list of filenames, each on a separate line.

-H header

Set the archive type to header. See star(1) for more information.

-I nm

Use nm as archive file name instead of stdin.

-k

Try to skip corrupt archive headers.

-L

Follow symbolic links as if they were files.

-M message

Define a message that is uses when switching media. This option is currently unsupported.

-O nm

Use nm as archive file name instead of stdout.

-P

Handle Access Control List (ACL) information in create and extract mode. See star -acl for more information.

-R nm

Reassign ownership and group for all files based on nm. This option is currently unsupported.

-s

Reverses the order of the bytes within each word. It is unclear what a word is supposed to be. This option is unsupported but not needed as scpio includes automatic byte order recognition.

-S

Reverses the order of the halfwords within each word. It is unclear what a word is supposed to be. This option is unsupported but not needed as scpio includes automatic byte order recognition.

-V

Special verbose. Print a dot for each file that is read or written. This option is currently unsupported.

The following other options are implemented as star extension to the Open Group standard:

-help

Prints a summary of the most important options for scpio(1) and exits.

-xhelp

Prints a summary of the less important options for scpio(1) and exits.

-version

Prints the scpio version number string and exists.

-/

Don't strip leading slashes from file names when extracting an archive.   See star(1) for more information.

..

Don't skip files that contain /../ in the name. See star(1) for more information.

-7z

run the input or output through a p7zip pipe - see option -z below.

Note that the p7zip program currently does not operate on a pipe but on a /tmp file copy and thus limits the maximum archive size.

-acl

Handle Access Control List (ACL) information in create and extract mode. See star(1) for more information.

artype=header

Set the archive type to header. See star(1) for more information.

-lzo

Run the input or output through a lzop pipe - see option -z below.

-bz

Run the input or output through a bzip2 pipe - see option -z below. As the -bz the -z options are non standard, it makes sense to omit -bz options the inside shell scripts. If you are going to extract a compressed archive that is located inside a plain file, scpio will auto detect compression and choose the right decompression option to extract.

bs=#

Set block size to #. You may use the same method as in dd(1) and sdd(1). See star(1) for more information.

-fifostats

Print fifo statistics at the end of a scpio run when the fifo has been in effect.

fs=#

Set fifo size to #. See star(1) for more information.

-no-fifo

Do not use a fifo to optimize data flow from/to tape. See star(1) for more information.

-no-fsync

Do not call fsync(2) for each file that has been extracted from the archive. See star(1) for more information.

-do-fsync

Call fsync(2) for each file that has been extracted from the archive. See star(1) for more information.

-no-statistics

Do not print statistic messages at the end of a scpio run.

-secure-links

Do not extract hard links or symbolic links if the link name (the target of the link) starts with a slash (/) or if /../ is contained in the link name.  See star(1) for more information.

-numeric

Use the numeric user/group fields in the listing rather than the default. See star(1) for more information.

-time

Print timing info. See star(1) for more information.

-xfflags

Store and extract extended file flags as found on BSD and Linux systems. See star -acl for more information.

-z

Run the input or output through a gzip pipe - see option -bz above. As the -bz the -z options are non standard, it makes sense to omit -bz options the inside shell scripts. If you are going to extract a compressed archive that is located inside a plain file, scpio will auto detect compression and choose the right decompression option to extract.

-zstd

run the input or output through a zstd pipe - see option -z above.

The following operands are supported:

directory

A pathname of an existing directory to be used as the target of scpio -p.

pattern

Expressions making use of a pattern-matching notation similar to that used by the shell 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.

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).

Note that scpio does not use fnmatch(3) based pattern matching as documented above, it rather uses the pattern matcher documented in match(1).

When the -o or -p options are used, the standard input is a text file containing a list of pathnames, one per line, to be copied.

When the -i option is used, the standard input is an archive file formatted in any way that is understood by the archive handling engine (see -H help option for a complete list).

The files identified by the pathnames in the standard input are of any type.

When the -r option is used, the file /dev/tty is used to write prompts and read responses.

Default.

When the -o option is used, the standard output is an archive file formatted as specified by pax with the -x cpio option. For better compatibility with SVR4-based systems that do not implement the cpio format correctly, scpio by default limits the length of file names to 256 bytes. Use scpio -H cpio to explicitly switch to the full POSIX 1003.1-1988 cpio archive format.

Otherwise, the standard output contains commentary in an unspecified format concerning the progress of the execution.

When the -o option is not used, the standard error contains commentary in an unspecified format concerning the progress of the execution. Otherwise, the standard error is used only for diagnostic messages.

Output files are created, as specified by the archive, when the -i or -p options are used.

None.

The following exit values are returned:

0

Successful completion.

>0

An error occurred.

If a file or directory cannot be created or overwritten, scpio continues with the next file in the archive or file to be added to the archive.

Archives created by scpio are portable between XSI-conformant systems provided the same procedures are used.

The shell metacharacter notation is not fully compatible with that used by the shell and the pax utility. Not all systems support the use of the negation character [! ...] in cpio patterns. Portable applications must avoid the use of this notation.

For portable communication of data between XSI-conformant systems, it is recommended that only characters defined in the ISO/IEC 646:1991 standard International Reference Version (equivalent to ASCII) 7-bit range of characters be used and that only characters defined in the Portable Filename Character Set be used for naming files. This recommendation is given because XSI-conformant systems support diverse codesets and run in various geographical areas and there is no single, well-established codeset that incorporates all of the characters of the languages of the various geographical areas.

The cpio archive format only supports file sizes up to 8 gigabytes.

Applications should migrate to the pax archive format which is the POSIX 1003.1-2001 standard archive format and based on an extended tar format.

None.

1. Copy the contents of a directory onto an archive:

ls | scpio -o >../cpio.out

2. Duplicate a directory hierarchy:

cd olddir
find . -depth -print | scpio -pd ../newdir

The following environment variables may affect the execution of scpio:

TZ

Determine the timezone used with date and time strings.

ar(1), find(1), sfind(1), ls(1), match(1), pax(1), spax(1), tar(1), star(1).

The default block size for cpio is 512 bytes, this slows down write speed. Use -B, -C, or bs= to set a different block size.

Scpio -iu is equivalent to star -xU -install -force-remove -remove-recursive and for this reason may remove nonempty directory trees in extrace mode without printing a warning.

The Open Group, have given us permission to reprint portions of their documentation. In the following statement, the phrase “this text” refers to portions of the system documentation.

Portions of this text are reprinted and reproduced in electronic form in the scpio manual, from The Open Group Base Specifications Issue 5, Copyright (C) 1997 by The Open Group. In the event of any discrepancy between these versions and the original specification, the original The Open Group Standard is the referee document. The original Standard can be obtained online at http://www.opengroup.org/unix/single_unix_specification_v2.

J. . org Schilling
Seestr. 110
D-13353 Berlin
Germany

Mail bugs and suggestions to:

joerg.schilling@fokus.fraunhofer.de or joerg@schily.net

opax(1), star(1), star(5).