HPUX tar[1]
tar in anderen Kapiteln des hpux Handbuch:
tar.4
tar(1) tar(1)
NAME
tar - tape file archiver
SYNOPSIS
tar key [arg...] [file | -C directory] ...
DESCRIPTION
tar saves and restores archives of files on a magnetic tape, a
flexible disk, or a regular file. Its actions are controlled by the
key argument. key is a string of characters containing an optional
version letter, exactly one function letter, and possibly one or more
function modifiers. The key string can be preceded by a hyphen (-)
(as when specifying options in other HP-UX commands), but it is not
necessary.
Next, an additional arg argument is required for each of the function
modifiers b or f used (see below). If both b and f modifiers are
specified, the order of the associated arg arguments must match the
order of the modifiers.
Each file argument specifies a file being saved or restored. If file
is a directory name, it refers to the files and (recursively)
subdirectories contained in that directory.
The version portion of the key determines in which format tar writes
the archive. tar can read either format regardless of the version.
The version is specified by one of the following letters:
N Write a new (POSIX) format archive. The new format
allows file names up to 256 characters in length, and
correctly archives and restores the following file types:
regular files, character and block special devices,
links, symbolic links, directories, and FIFO special
files. The new version also stores the user and group
name of each file and attempts to use these names to
determine the uid and gid of a file when restoring with
the p function modifier. This is the new default format.
O Write an old (pre-POSIX) format archive.
The function portion of the key is specified by one of the following
letters:
c Create a new archive; write from the beginning of the
archive instead of starting after the last file. Any
previous information in the archive is overwritten.
r Add the named file to the end of the archive.
t List the names of all the files on the archive. Adding
the v function modifier expands this listing to include
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the file modes and owner numbers. The names of all files
are listed each time they occur on the tape.
u Add any named file to the archive if it is not already
present or has been modified since last written on that
archive.
x Extract the named file from the archive and restore it to
the system. If a named file matches a directory whose
contents was written to the archive, this directory is
(recursively) extracted. If a named file on tape does
not exist on the system, the file is created as follows:
o The user, group, and other protections are restored
from the tape.
o The modification time is restored from the tape
unless the m function modifier is specified.
o The file owner (uid) and group owner (gid) are
normally that of the restoring process.
o The set-user-ID, set-group-ID, and sticky bits are
not set automatically. The o and p function
modifiers control the restoration of protection;
see below for more details.
If the files exist, their modes are not changed, but the
set-user-ID, set-group-ID and sticky bits are cleared.
If no file argument is given, the entire content of the
archive is extracted. Note that if several files with
the same name are on the archive, the last one overwrites
all earlier ones.
The following function modifiers can be used in addition to the
function letters listed above (note that some modifiers are
incompatible with some functions):
A Suppress warning messages that tar did not archive a file's
access control list. By default, tar writes a warning
message for each file with optional ACL entries.
b Cause tar to use the next arg argument as the blocking
factor for archive records. The default is 20; the maximum
is at least 20. However, if the f - modifier is used to
specify the standard input, the default blocking factor is
1.
Blocking factor is determined automatically when reading 9-
track tapes (key letters x and t). [On 9-track tapes, the
physical tape record length is the same as the block size.
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The block size is defined as the logical record size times
the blocking factor (number of logical records per block).]
The blocking factor must be specified when reading flexible
disks and cartridge tapes if they were written with a
blocking factor other than the default.
If a tar file is read using a blocking factor not equal to
the blocking used when the file was written, an error may
occur at the end of the file but there may or may not be an
actual error in the read. To prevent this problem, a
blocking factor of 1 can be used, although performance may
be reduced somewhat. tar writes logical records of 512
bytes, independent of how logical records may be defined
elsewhere by other programs (such as variable-length records
(lines) within an ASCII text file).
f Cause tar to use the next arg argument as the name of the
archive instead of /dev/rmt/0m. If the name of the file is
-, tar writes to the standard output or reads from the
standard input, whichever is appropriate, and the default
blocking factor becomes 1. Thus, tar can be used as the
head or tail of a pipeline. tar can also be used to move
hierarchies with the command:
cdfromdir; tar cf - . | (cd todir ; tar xf -)
h Force tar to follow symbolic links as if they were normal
files or directories. Normally, tar does not follow
symbolic links.
H Cause all entries in hidden directories (context-dependent
files) to be written to the archive (see cdf(4)). Normally,
tar only writes the entry in the CDF that matches the
context of the tar process. See getcontext(2). This
modifier works only when writing archives. When reading
archives, tar automatically restores hidden directories if
the archive was created with the H modifier.
l Tell tar to complain if it cannot resolve all of the links
to the files being saved. If l is not specified, no error
messages are printed.
m Tell tar not to restore the modification time written on the
archive. The modification time of the file will be the time
of extraction.
o Suppress writing certain directory information that older
versions of tar cannot handle on input. tar normally writes
information specifying owners and modes of directories in
the archive. Earlier versions of tar, when encountering
this information, give error messages of the form:
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name/: cannot create.
This function modifier suppresses writing that information.
When o is used for reading, it causes the extracted file to
take on the user and group ID (uid and gid) of the user
running the program rather than those of the tape. This is
the default for the ordinary user and can be overridden, to
the extent that system protections allow, by using the p
function modifier.
p Cause file to be restored to the original modes and
ownerships written on the archive, if possible. This is the
default for the superuser, and can be overridden by the o
function modifier. If system protections prevent the
ordinary user from executing chown(), the error is ignored,
and the ownership is set to that of the restoring process
(see chown(2)). Set-user-ID, set-group-ID, and sticky bit
information are restored as allowed by the protections
defined by chmod() if the chown operation above succeeds.
# d Specify a particular tape drive and density where # is a
tape drive number (0,...,7), and d is the density: (l = low
(800 bpi), m = medium (1600 bpi), or h = high (6250 bpi)).
This modifier selects the drive on which the nine-track tape
is mounted. The default is 0m.
v Normally, tar does its work silently. The v (verbose)
function modifier causes tar to type the name of each file
it treats, preceded by the function letter. With the t
function, v gives more information about the tape entries
than just the name.
V Same as the v function modifier except that when using the t
option, tar also prints out a letter indicating the type of
the archived file.
w Cause tar to print the action being taken, followed by the
name of the file, then wait for the user's confirmation. If
the user answers y, the action is performed. Any other
input means ``no''.
The following option can be included in the file list:
-Cdirectory tar performs a chdir() to directory (see
chdir(2)). This allows multiple directories not
related by a close or common parent to be archived
using short relative path names.
When end-of-tape is reached, tar prompts the user for a new special
file and continues.
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If a nine-track tape drive is used as the output device, it must be
configured in Berkeley-compatibility mode (see mt(7)).
EXTERNAL INFLUENCES
Environment Variables
LC_TIME determines the format and contents of date and time strings
output when listing the contents of an archive with the -v option.
LANG determines the language equivalent of y (for yes/no queries).
If LC_TIME is not specified in the environment or is set to the empty
string, the value of LANG is used as a default for each unspecified or
empty variable. If LANG is not specified or is set to the empty
string, a default of "C" (see lang(5)) is used instead of LANG. If
any internationalization variable contains an invalid setting, tar
behaves as if all internationalization variables are set to "C". See
environ(5).
International Code Set Support
Single- and multi-byte character code sets are supported.
ERRORS
tar complains about bad key characters and tape read/write errors.
tar complains if not enough memory is available to hold the link
tables.
EXAMPLES
Create a new archive on /dev/rfd.0 and copies file1 and file2 onto it,
using the default blocking factor of 20. The key is made up of one
function letter (c) and two function modifiers (v, and f):
tar cvf /dev/rfd.0 file1 file2
Archive files from /usr/include and /etc:
tar cv -C /usr/include -C /etc
WARNINGS
The default version has changed from O to N beginning with HP-UX
Release 8.0.
Due to internal limitations in the header structure, not all file
names of fewer than 256 characters fit when using the N version key.
If a file name does not fit, tar prints a message and does not archive
the file.
Link names are still limited to 100 characters when using the N
version key.
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There is no way to ask for the n-th occurrence of a file.
Tape errors are handled ungracefully.
The u function key can be slow.
If the archive is on a flexible disk or cartridge tape, and if the
blocking factor specified on output is not the default, the same
blocking factor must be specified on input. This is because the
blocking factor is not explicitly stored on the archive. Updating the
archive without following this rule can destroy it.
Some previous versions of tar have claimed to support selective
listing of file names using the t function key with a list. This
appears to be an error in the documentation because the capability
does not appear in the original source code.
There is no way to restore an absolute path name to a relative
position.
tar always pads information written to an archive up to the next
multiple of the block size. Therefore, if you are creating a small
archive and write out one block of information, tar reports that one
block was written, but the actual size of the archive might be larger
if the b function modifier is used.
Note that tar c0m is not the same as tar cm0.
Do not create archives on block special devices. Attempting to do so
can causes excessive wear, leading to premature drive hardware
failure.
Access Control Lists
Access control list descriptions in this entry apply only to standard
HP-UX operating systems. If HP-UX BLS software has been installed,
access control lists are handled differently. Refer to HP-UX BLS
documentation for information about access control lists in the HP-UX
BLS environment.
AUTHOR
tar was developed by AT&T, the University of California, Berkeley, HP
and POSIX.
FILES
/dev/rmt/*
/dev/rfd.*
/tmp/tar*
DEPENDENCIES
Series 700/800
The -r and -u options are not supported on QIC devices. If these
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options are used with QIC devices, tar fails and displays the message:
tar: option not supported for QIC devices
SEE ALSO
ar(1), cpio(1), mt(7), getcontext(2), cdf(4), acl(5).
STANDARDS CONFORMANCE
tar: SVID2, XPG2, XPG3
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