Its actions are controlled by the
is a string of characters containing
at most one function letter and possibly
one or more function modifiers.
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 key is specified by one of the following letters:
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
Note that if multiple entries specifying the same file
are on the tape, the last one overwrites
The names of the specified files are listed each time they occur
If no file argument is given,
all of the names on the tape are listed.
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.
Create a new tape; writing begins on the beginning
of the tape instead of after the last file.
The following characters may be used in addition to the letter
which selects the function desired.
modifier selects the drive on which the tape is mounted.
option causes it to type the name of each file it treats
preceded by the function letter.
gives more information about the
tape entries than just the name.
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
to use the next argument as the name of the archive instead
If the name of the file is `\-', tar writes to
standard output or reads from standard input, whichever is
can be used as the head or tail of a filter chain
can also be used to move hierarchies with the command
cd fromdir; tar cf - . | (cd todir; tar xf -)
to use the next argument as the blocking factor for tape
records. The default is 1, the maximum is 20. This option
should only be used with raw magnetic tape archives (See
The block size is determined automatically when reading
tapes (key letters `x' and `t').
to complain if it cannot resolve all of the links
to the files dumped. If this is not specified, no
error messages are printed.
to not restore the modification times.
will be the time of extraction.
Complaints about bad key characters and tape read/write errors.
Complaints if enough memory is not available to hold
There is no way to ask for the
Tape errors are handled ungracefully.
option should not be used with archives that are
going to be updated. The current magtape driver cannot
If the archive is on a disk file the
option should not be used at all, as updating
an archive stored in this manner can destroy it.
The current limit on file name length is