32v 1m tar
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TAR(1) UNIX Programmer's Manual TAR(1)
tar - tape archiver
tar [ key ] [ name ... ]
_T_a_r saves and restores files on magtape. Its actions are controlled by the _k_e_y argument. The _k_e_y is a string of characters containing at most one function letter and possi- bly 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) sub- directories 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 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.
0,...,7 This modifier selects the drive on which the tape is mounted. The default is 1.
v Normally _t_a_r does its work silently. The v (ver- bose) 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 _t_a_r to print the action to be taken fol- lowed by file name, then wait for user confirma- tion. If a word beginning with `y' is given, the action is performed. Any other input means don't do it.
f causes _t_a_r to use the next argument as the name of the archive instead of /dev/mt?. If the name of the file is `-', tar writes to standard output or reads from standard input, whichever is appropri- ate. Thus, _t_a_r can be used as the head or tail of a filter chain _T_a_r can also be used to move hierarchies with the command cd fromdir; tar cf - . | (cd todir; tar xf -)
b causes _t_a_r to use the next argument as the block- ing factor for tape records. The default is 1, the maximum is 20. This option should only be used with raw magnetic tape archives (See f above).
l tells _t_a_r to complain if it cannot resolve all of the links to the files dumped. If this is not specified, no error meesages are printed.
Complaints about bad key characters and tape read/write errors. Complaints if enough memory is not available to hold the link tables.
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 b option should not be used with archives that are going to be updated. The current magtape driver cannot backspace raw magtape. If the archive is on a disk file the b 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 100 characters.