TAR(1) GENIX Programmer's Manual TAR(1)
NAME
tar - tape archiver
SYNOPSIS
tar [ key ] [ name ... ]
DESCRIPTION
Tar saves and restores files on magtape. Its 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 modif-
iers. Other arguments to the command are file or directory names
specifying which files are to be dumped or restored. 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 pos-
sible). If no file argument is given, the entire content of
the tape is extracted. Note that if multiple entries speci-
fying 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.
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 mes-
sage of the form
"<name>/: cannot create".
This option will suppress the directory information.
p This option says to restore files to their original modes,
ignoring the present umask(2). Setuid and sticky informa-
tion will also be restored to the super-user.
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TAR(1) GENIX Programmer's Manual TAR(1)
The following characters may be used in addition to the letter which
selects the function desired.
0,...,7 This modifier selects an alternate drive on which the tape
is mounted. (The default is drive 0 at 1600 bpi, which is
normally /dev/rmt8.)
v Normally tar does its work silently. The v (verbose)
option causes it 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.
w causes tar to print 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 performed. Any
other input means don't do it.
f causes tar to use the next argument as the name of the
archive instead of /dev/rmt?. 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 causes tar to use 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 to not restore the modification times. The mod
time will be the time of extraction.
Previous restrictions dealing with tar's inability to properly han-
dle blocked archives have been lifted.
FILES
/dev/rmt?
/tmp/tar*
DIAGNOSTICS
Complaints about bad key characters and tape read/write errors.
Complaints if enough memory is not available to hold the link
tables.
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TAR(1) GENIX Programmer's Manual TAR(1)
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.
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