paxtar —
tape
archiver
paxtar |
{crtux}[014578abefHhJjLmOoPpqsvwXZz]
[blocking-factor |
archive |
replstr]
[-C
directory]
[-I
file]
[file ...] |
paxtar |
{-crtux}
[-014578aeHhJjLmOoPpqvwXZz]
[-b blocking-factor]
[-C directory]
[-D format-options]
[-f archive]
[-I file]
[-M flag]
[-s replstr]
[file ...] |
The
paxtar command creates, adds files to, or
extracts files from an archive file in “tar” (strictly speaking,
ustar) format. A tar archive is often stored on a
magnetic tape, but can be stored equally well on a floppy, CD-ROM, or in a
regular disk file.
In the first (legacy) form, all option flags except for
-C and
-I must be
contained within the first argument to
paxtar and
must not be prefixed by a hyphen (‘-’). Option arguments, if
any, are processed as subsequent arguments to
paxtar and are processed in the order in which
their corresponding option flags have been presented on the command line.
In the second and preferred form, option flags may be given in any order and are
immediately followed by their corresponding option argument values.
One of the following flags must be present:
- -c
- Create new archive, or overwrite an existing archive,
adding the specified files to it.
- -r
- Append the named new files to existing archive. Note that
this will only work on media on which an end-of-file mark can be
overwritten.
- -t
- List contents of archive. If any files are named on the
command line, only those files will be listed. The
file arguments may be specified as glob
patterns (see glob(7) for more information),
in which case paxtar will list all archive
members that match each pattern.
- -u
- Alias for -r.
- -x
- Extract files from archive. If any files are named on the
command line, only those files will be extracted from the archive. The
file arguments may be specified as glob
patterns (see glob(7) for more information),
in which case paxtar will extract all archive
members that match each pattern.
If more than one copy of a file exists in the archive, later copies will
overwrite earlier copies during extraction. The file mode and modification
time are preserved if possible. The file mode is subject to modification
by the umask(2).
In addition to the flags mentioned above, any of the following flags may be
used:
- -a
- Guess the compression utility based on the archive
filename. Inability to guess will result in quietly not using any
compression. This option only exists for semi-compatibility with GNU
tar; it is strongly recommended to archive to
stdout and pipe into an external compression utility with appropriate
arguments instead:
tar -cf - foo | xz -2e
>foo.txz
-
-b
blocking-factor
- Set blocking factor to use for the archive.
paxtar uses 512-byte blocks. The default is
20, the maximum is 126. Archives with a blocking factor larger than 63
violate the POSIX standard and will not be portable to all systems.
-
-C
directory
- This is a positional argument which sets the working
directory for the following files. When extracting, files will be
extracted into the specified directory; when creating, the specified files
will be matched from the directory.
-
-D
format-options
- Specify the archive format and format options, separated by
comma. paxtar currently supports the
following formats and options:
- ar
- The Unix Archiver library format. This format matches
APT repositories and the BSD ar(1)
specification, not GNU binutils (which can however read them) or SYSV
systems. See ar(5) on some operating
systems for more information.
- bcpio
- The old binary cpio format. The default blocksize for
this format is 5120 bytes. This format is not very portable and should
not be used when other formats are available. Inode and device
information about a file (used for detecting file hard links by this
format), which may be truncated by this format, is detected by
paxtar and is repaired.
- cpio
- The extended cpio interchange format specified in the
IEEE Std 1003.2
(“POSIX.2”) standard. The default blocksize for
this format is 5120 bytes. Inode and device information about a file
(used for detecting file hard links by this format), which may be
truncated by this format, is detected by
paxtar and is repaired.
- sv4cpio
- The System V release 4 cpio. The default blocksize for
this format is 5120 bytes. Inode and device information about a file
(used for detecting file hard links by this format), which may be
truncated by this format, is detected by
paxtar and is repaired.
- sv4crc
- The System V release 4 cpio with file CRC checksums.
The default blocksize for this format is 5120 bytes. Inode and device
information about a file (used for detecting file hard links by this
format), which may be truncated by this format, is detected by
paxtar and is repaired.
- tar
- The old BSD tar format as found
in 4.3BSD. The default blocksize for this
format is 10240 bytes. Pathnames stored by this format must be 100
characters or less in length. Only regular files, hard links, soft
links, and directories will be archived (other filesystem types are
not supported).
For backwards compatibility with even older tar formats, the
write_opt=nodir option can be used when
writing an archive to omit the storage of directories.
- ustar
- The extended tar interchange format specified in the
IEEE Std 1003.2
(“POSIX.2”) standard. The default blocksize for
this format is 10240 bytes. Filenames stored by this format must be
100 characters or less in length; the total pathname must be 256
characters or less.
paxtar will detect and report any file that it
is unable to store or extract as the result of any specific archive format
restrictions. The individual archive formats may impose additional
restrictions on use. Typical archive format restrictions include (but are
not limited to): file pathname length, file size, link pathname length,
and the type of the file.
- -e
- Stop after the first error.
-
-f
archive
- Filename where the archive is stored. Defaults to
/dev/rst0. If set to hyphen
(‘-’) standard output is used. See also the
TAPE
environment variable.
- -H
- Follow symlinks given on the command line only.
- -h
- Follow symbolic links as if they were normal files or
directories. In extract mode this means that a directory entry in the
archive will not overwrite an existing symbolic link, but rather what the
link ultimately points to.
-
-I
file
- This is a positional argument which reads the names of
files to archive or extract from the given file, one per line.
- -J
- Use the xz utility to compress the archive.
- -j
- Use the bzip2 utility to compress the archive.
- -L
- Synonym for the -h
option.
-
-M
flag
- Configure the archive normaliser.
flag is either a numeric value compatible
to strtonum(3) which is directly stored in
the flags word, or one of the following values, optionally prefixed with
“no-” to turn them off:
- inodes
- 0x0001: Serialise inodes, zero device info.
(cpio, sv4cpio, sv4crc)
- links
- 0x0002: Store content of hard links only once.
(cpio, sv4cpio, sv4crc)
- mtime
- 0x0004: Zero out the file modification time.
(ar, cpio, sv4cpio, sv4crc, ustar)
- uidgid
- 0x0008: Set owner to 0:0
(
root
:wheel
).
(ar, cpio, sv4cpio, sv4crc, ustar)
- verb
- 0x0010: Debug this option.
- debug
- 0x0020: Debug file header storage.
- lncp
- 0x0040: Extract hard links by copy if link fails.
- numid
- 0x0080: Use only numeric uid and gid values.
(ustar)
- gslash
- 0x0100: Append a slash after directory names.
(ustar)
- set
- 0x0003: Keep ownership and mtime intact.
- dist
- 0x008B: Clean everything except mtime.
- norm
- 0x008F: Clean everything.
- root
- 0x0089: Clean owner and device information.
When creating an archive and verbosely listing output, these normalisation
operations are not reflected in the output, because they are made only
after the output has been shown.
This option is only implemented for the ar, cpio, sv4cpio, sv4crc, and ustar
file format writing routines.
- -m
- Do not preserve modification time.
- -O
- If reading, extract files to standard output.
If writing, write old-style (non-POSIX) archives.
- -o
- If writing, write old-style (non-POSIX) archives.
Don't write directory information that the older (V7) style
tar is unable to decode. Same as
-D
tar,write_opt=nodir.
- -P
- For security reasons, paxtar
skips pathnames containing dotdot (“..”) components and
strips leading slashes (‘/’) from pathnames by default; this
option disables that behaviour.
- -p
- Preserve user and group ID as well as file mode regardless
of the current umask(2). The setuid and
setgid bits are only preserved if the user and group ID could be
preserved. Only meaningful in conjunction with the
-x flag.
- -q
- Select the first archive member that matches each
file operand. No more than one archive
member is matched for each file. When
members of type directory are matched, the file hierarchy rooted at that
directory is also matched.
-
-s
replstr
- Modify the archive member names according to the
substitution expression replstr, using
the syntax of the ed(1) utility regular
expressions. file arguments may be given
to restrict the list of archive members to those specified.
The format of these regular expressions is
/old/new/[gp]
As in ed(1),
old is a basic regular expression (see
re_format(7)) and
new can contain an ampersand
(‘&
’),
‘\n
’
(where n is a digit) back-references, or
subexpression matching. The old string
may also contain newline characters. Any non-null character can be used as
a delimiter (‘/
’ is shown here).
Multiple -s expressions can be specified. The
expressions are applied in the order they are specified on the command
line, terminating with the first successful substitution.
The optional trailing g continues to apply the
substitution expression to the pathname substring, which starts with the
first character following the end of the last successful substitution. The
first unsuccessful substitution stops the operation of the
g option. The optional trailing
p will cause the final result of a successful
substitution to be written to standard error in the following format:
original-pathname
>>
new-pathname
File or archive member names that substitute to the empty string are not
selected and will be skipped.
- -v
- Verbose operation mode. If -v
is specified multiple times or if the -t
option is also specified, paxtar will use a
long format for listing files, similar to
ls(1) -l.
- -w
- Interactively rename files. This option causes
paxtar to prompt the user for the filename to
use when storing or extracting files in an archive.
- -X
- Do not cross mount points in the filesystem.
- -Z
- Use the compress(1) utility to
compress the archive.
- -z
- Use the gzip(1) utility to
compress the archive.
The options [
-014578] can
be used to select one of the compiled-in backup devices,
/dev/rstN.
TMPDIR
- Path in which to store temporary files.
TAPE
- Default tape device to use instead of
/dev/rst0. If set to hyphen
(‘-’) standard output is used.
- /dev/rst0
- default archive name
The
paxtar utility exits with one of the following
values:
- 0
- All files were processed successfully.
- 1
- An error occurred.
Create an archive on the default tape drive, containing the files named
bonvole and
sekve:
$ paxtar c bonvole sekve
Output a
gzip(1) compressed archive containing the
files
bonvole and
sekve to a file called
foriru.tar.gz:
$ paxtar zcf foriru.tar.gz bonvole
sekve
Verbosely create an archive, called
backup.tar.gz,
of all files matching the shell
glob(7) function
*.c:
$ paxtar zcvf backup.tar.gz *.c
Verbosely list, but do not extract, all files ending in
.jpeg from a compressed archive named
backup.tar.gz. Note that the glob pattern has
been quoted to avoid expansion by the shell:
$ paxtar tvzf backup.tar.gz
'*.jpeg'
For more detailed examples, see
pax(1).
Whenever
paxtar cannot create a file or a link when
extracting an archive or cannot find a file while writing an archive, or
cannot preserve the user ID, group ID, file mode, or access and modification
times when the
-p option is specified, a
diagnostic message is written to standard error and a non-zero exit value will
be returned, but processing will continue. In the case where
paxtar cannot create a link to a file, unless
-M lncp is
given,
paxtar will not create a second copy of
the file.
If the extraction of a file from an archive is prematurely terminated by a
signal or error,
paxtar may have only partially
extracted the file the user wanted. Additionally, the file modes of extracted
files and directories may have incorrect file bits, and the modification and
access times may be wrong.
If the creation of an archive is prematurely terminated by a signal or error,
paxtar may have only partially created the
archive, which may violate the specific archive format specification.
ar(1),
cpio(1),
pax(1),
paxcpio(1),
tar(1),
deb(5)
A
tar command first appeared in
Version 7 AT&T UNIX.
Keith Muller at the University of California,
San Diego. MirBSD extensions by
mirabilos
⟨
[email protected]⟩.
The flags
-aDJjLMo are not portable to other
implementations of
tar where they may have a
different meaning or not exist at all.
This implementation may have support for other non-standard options that are
undocumented because removal-inducing deprecation was issued.
The
pax file format is not yet supported.