PAX(C) UNIX System V
Name
pax - portable archive exchange
Syntax
pax [-cimopuvy] [-f archive] [-s replstr] [-t device]
[pattern...]
pax -r [-cimnopuvy] [-f archive] [-s replstr] [-t device]
[pattern...]
pax -w [-adimuvy] [-b blocking] [-f archive] [-s replstr]
[-t device] [-x format] [pathname...]
pax -rw [-ilmopuvy] [-s replstr] [pathname...] directory
Description
pax reads and writes archive files which conform to the
Archive/Interchange File Format specified in IEEE Std.
1003.1-1988. pax can also read, but not write, a number of
other file formats in addition to those specified in the
Archive/Interchange File Format description. Support for
these traditional file formats, such as V7 tar and System V
binary cpio format archives, is provided for backward
compatibility and to maximize portability.
pax will also support traditional cpio and System V tar
interfaces if invoked with the name ``cpio'' or ``tar''
respectively. See the cpio(C) or tar(C) manual pages for
more details.
Combinations of the -r and -w command line arguments specify
whether pax will read, write or list the contents of the
specified archive, or move the specified files to another
directory.
The command line arguments are:
-w writes the files and directories specified by pathname
operands to the standard output together with the
pathname and status information prescribed by the
archive format used. A directory pathname operand
refers to the files and (recursively) subdirectories of
that directory. If no pathname operands are given,
then the standard input is read to get a list of
pathnames to copy, one pathname per line. In this
case, only those pathnames appearing on the standard
input are copied.
-r pax reads an archive file from the standard input.
Only files with names that match any of the pattern
operands are selected for extraction. The selected
files are conditionally created and copied relative to
the current directory tree, subject to the options
described below. By default, the owner and group of
selected files will be that of the invoking process,
and the permissions and modification times will be the
sames as those in the archive.
The supported archive formats are automatically
detected on input. The default output format is ustar,
but may be overridden by the -x format option described
below.
-rw pax reads the files and directories named in the
pathname operands and copies them to the destination
directory. A directory pathname operand refers to the
files and (recursively) subdirectories of that
directory. If no pathname operands are given, the
standard input is read to get a list of pathnames to
copy, one pathname per line. In this case, only those
pathnames appearing on the standard input are copied.
The directory named by the directory operand must exist
and have the proper permissions before the copy can
occur.
If neither the -r or -w options are given, then pax will
list the contents of the specified archive. In this mode,
pax lists normal files one per line, hard link pathnames as
pathname == linkname
and symbolic link pathnames (if supported by the
implementation) as
pathname -> linkname
where pathname is the name of the file being extracted, and
linkname is the name of a file which appeared earlier in the
archive.
If the -v option is specified, then pax list normal
pathnames in the same format used by the ls utility with the
-l option. Hard links are shown as
<ls -l listing> == linkname
and symbolic links (if supported) are shown as
<ls -l listing> -> linkname
pax is capable of reading and writing archives which span
multiple physical volumes. Upon detecting an end of medium
on an archive which is not yet completed, pax will prompt
the user for the next volume of the archive and will allow
the user to specify the location of the next volume.
Options
The following options are available:
-a The files specified by pathname are appended to
the specified archive.
-b blocking
Block the output at blocking bytes per write to
the archive file. A k suffix multiplies blocking
by 1024, a b suffix multiplies blocking by 512 and
a m suffix multiplies blocking by 1048576 (1
megabyte). If not specified, blocking is
automatically determined on input and is ignored
for -rw.
-c Complement the match sense of the the pattern
operands.
-d Intermediate directories not explicitly listed in
the archive are not created. This option is
ignored unless the -r option is specified.
-f archive
The archive option specifies the pathname of the
input or output archive, overriding the default of
standard input for -r or standard output for -w.
-i Interactively rename files. Substitutions
specified by -s options (described below) are
performed before requesting the new file name from
the user. A file is skipped if an empty line is
entered and pax exits with an exit status of 0 if
EOF is encountered.
-l Files are linked rather than copied when possible.
-m File modification times are not retained.
-n When -r is specified, but -w is not, the pattern
arguments are treated as ordinary file names.
Only the first occurrence of each of these files
in the input archive is read. The pax utility
exits with a zero exit status after all files in
the list have been read. If one or more files in
the list is not found, pax writes a diagnostic to
standard error for each of the files and exits
with a non-zero exit status. the file names are
compared before any of the -i, -s, or -y options
are applied.
-o Restore file ownership as specified in the
archive. The invoking process must have
appropriate privileges to accomplish this.
-p Preserve the access time of the input files after
they have been copied.
-s replstr
File names are modified according to the
substitution expression using the syntax of ed(C)
as shown:
-s /old/new/[gp]
Any non null character may be used as a delimiter
(a / is used here as an example). Multiple -s
expressions may be specified; the expressions are
applied in the order specified terminating with
the first successful substitution. The optional
trailing p causes successful mappings to be listed
on standard error. The optional trailing g causes
the old expression to be replaced each time it
occurs in the source string. Files that
substitute to an empty string are ignored both on
input and output.
-t device
The device option argument is an implementation-
defined identifier that names the input or output
archive device, overriding the default of standard
input for -r and standard output for -w.
-u Copy each file only if it is newer than a pre-
existing file with the same name. This implies
-a.
-v List file names as they are encountered. Produces
a verbose table of contents listing on the
standard output when both -r and -w are omitted,
otherwise the file names are printed to standard
error as they are encountered in the archive.
-x format
Specifies the output archive format. The input
format, which must be one of the following, is
automatically determined when the -r option is
used. The supported formats are:
cpio The extended CPIO interchange format specified in
Extended CPIO Format in IEEE Std. 1003.1-1988.
ustar The extended TAR interchange format specified in
Extended TAR Format in IEEE Std. 1003.1-1988.
This is the default archive format.
-y Interactively prompt for the disposition of each
file. Substitutions specified by -s options
(described above) are performed before prompting
the user for disposition. EOF or an input line
starting with the character q caused pax to exit.
Otherwise, an input line starting with anything
other than y causes the file to be ignored. This
option cannot be used in conjunction with the -i
option.
Only the last of multiple -f or -t options take effect.
When writing to an archive, the standard input is used as a
list of pathnames if no pathname operands are specified.
The format is one pathname per line. Otherwise, the
standard input is the archive file, which is formatted
according to one of the specifications in
Archive/Interchange File format in IEEE Std. 1003.1-1988, or
some other implementation-defined format.
The user ID and group ID of the process, together with the
appropriate privileges, affect the ability of pax to restore
ownership and permissions attributes of the archived files.
(See format-reading utility in Archive/Interchange File
Format in IEEE Std. 1003.1-1988.)
The options -a, -c, -d, -i, -l, -p, -t, -u, and -y are
provided for functional compatibility with the historical
cpio and tar utilities. The option defaults were chosen
based on the most common usage of these options, therefore,
some of the options have meanings different than those of
the historical commands.
Operands
The following operands are available:
directory The destination directory pathname for copies when
both the -r and -w options are specified. The
directory must exist and be writable before the
copy or and error results.
pathname
A file whose contents are used instead of the
files named on the standard input. When a
directory is named, all of its files and
(recursively) subdirectories are copied as well.
pattern
A pattern is given in the standard shell pattern
matching notation. The default if no pattern is
specified is *, which selects all files.
Examples
The following command
pax -w -f /dev/rmt0 .
copies the contents of the current directory to tape drive 0.
The commands
mkdir newdir
cd olddir
pax -rw . newdir
copies the contents of olddir to newdir .
The command
pax -r -s ',//*usr//*,,' -f pax.out
reads the archive pax.out with all files rooted in "/usr" in
the archive extracted relative to the current directory.
Files
/dev/tty used to prompt the user for information when the
-i or -y options are specified.
See Also
cpio(C), find(C), tar(C), cpio(M), tar(F)
Diagnostics
pax will terminate immediately, without processing any
additional files on the command line or in the archive.
pax will exit with one of the following values:
0 All files in the archive were processed successfully.
>0 pax aborted due to errors encountered during operation.
Notes
Special permissions may be required to copy or extract
special files.
Device, user ID, and group ID numbers larger than 65535
cause additional header records to be output. These records
are ignored by some historical version of cpio(C) and
tar(C).
The archive formats described in Archive/Interchange File
Format have certain restrictions that have been carried over
from historical usage. For example, there are restrictions
on the length of pathnames stored in the archive.
When getting an ``ls -l'' style listing on tar format
archives, link counts are listed as zero since the ustar
archive format does not keep link count information.
Copyright
Copyright (c) 1989 Mark H. Colburn.
All rights reserved.
Redistribution and use in source and binary forms are
permitted provided that the above copyright notice is
duplicated in all such forms and that any documentation,
advertising materials, and other materials related to such
distribution and use acknowledge that the software was
developed by Mark H. Colburn and sponsored by The USENIX
Association.
THE SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING,
WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
Author
Mark H. Colburn
NAPS International
117 Mackubin Street, Suite 1
St. Paul, MN 55102
mark@jhereg.MN.ORG
Sponsored by The USENIX Association for public distribution.
(printed 8/25/89) PAX(C)