TAR(1)TAR(1)NAMEtar - tape archiver
SYNOPSIStar [ key ] [ name ... ]
DESCRIPTION
Tar saves and restores multiple files on a single file (usually a
magnetic tape, but it can be any file). Tar's actions are controlled
by the key argument. The key is a string of characters containing at
most one function letter and possibly one or more function modifiers.
Other arguments to tar are file or directory names specifying which
files to dump or restore. In all cases, appearance of a directory name
refers to the files and (recursively) subdirectories of that directory.
The function portion of the key is specified by one of the following
letters:
r The named files are written on the end of the tape. The c
function implies this.
x The named files are extracted from the tape. If the named file
matches a directory whose contents had been written onto the
tape, this directory is (recursively) extracted. The owner,
modification time, and mode are restored (if possible). If no
file argument is given, the entire content of the tape is
extracted. Note that if multiple entries specifying the same
file are on the tape, the last one overwrites all earlier.
t The names of the specified files are listed each time they
occur on the tape. If no file argument is given, all of the
names on the tape are listed.
u The named files are added to the tape if either they are not
already there or have been modified since last put on the tape.
c Create a new tape; writing begins on the beginning of the tape
instead of after the last file. This command implies r.
The following characters may be used in addition to the letter which
selects the function desired.
o On output, tar normally places information specifying owner
and modes of directories in the archive. Former versions of
tar, when encountering this information will give error
message of the form
"<name>/: cannot create".
This modifier will suppress the directory information.
p This modifier says to restore files to their original modes,
ignoring the present umask(2). Setuid and sticky information
will also be restored to the super-user.
0, ..., 9 This modifier selects an alternate drive on which the tape is
mounted. The default is drive 0 at 1600 bpi, which is
normally /dev/rxt8.
v Normally tar does its work silently. The v (verbose) option
makes tar print the name of each file it treats preceded by
the function letter. With the t function, the verbose option
gives more information about the tape entries than just their
names.
w Tar prints the action to be taken followed by file name, then
wait for user confirmation. If a word beginning with `y' is
given, the action is done. Any other input means don't do it.
f Tar uses the next argument as the name of the archive instead
of /dev/rxt?. If the name of the file is `-', tar writes to
standard output or reads from standard input, whichever is
appropriate. Thus, tar can be used as the head or tail of a
filter chain. Tar can also be used to move hierarchies with
the command
cd fromdir; tar cf - . | (cd todir; tar xf -)
b Tar uses the next argument as the blocking factor for tape
records. The default is 20 (the maximum). This option should
only be used with raw magnetic tape archives (See f above).
The block size is determined automatically when reading tapes
(key letters `x' and `t').
l tells tar to complain if it cannot resolve all of the links
to the files dumped. If this is not specified, no error
messages are printed.
m tells tar not to restore the modification times. The
modification time will be the time of extraction.
h Force tar to follow symbolic links as if they were normal
files or directories. Normally, tar does not follow symbolic
links.
B Forces input and output blocking to 20 blocks per record.
This option was added so that tar can work across a
communications channel where the blocking may not be
maintained.
C If a file name is preceded by -C, then tar will perform a
chdir(2) to that file name. This allows multiple directories
not related by a close common parent to be archived using
short relative path names. For example, to archive files
from /NextDeveloper/Headers and from /etc, one might use
tar c -C /NextDeveloper Headers -C / etc
Previous restrictions dealing with tar's inability to properly handle
blocked archives have been lifted.
FILES
/dev/rxt?
/tmp/tar*
SEE ALSOtar(5)DIAGNOSTICS
Complaints about bad key characters and tape read/write errors.
Complaints if enough memory is not available to hold the link tables.
BUGS
There is no way to ask for the n-th occurrence of a file.
Tape errors are handled ungracefully.
The u option can be slow.
The current limit on file name length is 100 characters.
There is no way selectively to follow symbolic links.
When extracting tapes created with the r or u options, directory
modification times may not be set correctly.
7th Edition May 12, 1986 TAR(1)