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TAR(1)		    UNIX Programmer's Manual		   TAR(1)



[1mNAME
     [0mtar, tar0 - tape archiver

[1mSYNOPSIS
     tar [0m[ key ] [ name ... ]

[1mDESCRIPTION
     [0m_T_a_r saves and restores multiple files on a single file (usu-
     ally a magnetic tape, but it can be any file). _T_a_r's 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 _t_a_r
     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:

     [1mr	     [0mThe named files are written on the end of the tape.
	     The [1mc [0mfunction implies this.

     [1mx	     [0mThe 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.

     [1mt	     [0mThe 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.

     [1mu	     [0mThe named files are added to the tape if either they
	     are not already there or have been modified since
	     last put on the tape.

     [1mc	     [0mCreate a new tape; writing begins on the beginning
	     of the tape instead of after the last file.  This
	     command implies [1mr[0m.

     The following characters may be used in addition to the
     letter which selects the function desired.

     [1me	       [0mUse the X/Open extended header format on output.
	       This supports file types not recognised by older
	       versions of tar, i.e. block/character devices and
	       named pipes.  It will also seriously confuse older



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TAR(1)		    UNIX Programmer's Manual		   TAR(1)



	       versions of tar if they try to read an archive
	       with extended headers.  The header format is
	       determined automatically when reading tapes (key
	       letters 'x' and 't').

     [1mo	       [0mOn output, tar normally places information speci-
	       fying owner and modes of directories in the
	       archive.  Former versions of tar, when encounter-
	       ing this information will give error message of
	       the form
		    "<name>/: cannot create".
	       This modifier will suppress the directory informa-
	       tion.

     [1mp	       [0mThis modifier says to restore files to their ori-
	       ginal modes, ignoring the present _u_m_a_s_k(2).
	       Setuid and sticky information will also be
	       restored to the super-user.

     [1m0, ..., 9 [0mThis modifier selects an alternate drive on which
	       the tape is mounted.  The device name will be
	       formed by appending the option digit to /_d_e_v/_t_a_p_e
	       (the default device is /_d_e_v/_t_a_p_e with no postfix).

     [1mv	       [0mNormally _t_a_r does its work silently.  The [1mv [0m(ver-
	       bose) option makes _t_a_r print the name of each file
	       it treats preceded by the function letter.  With
	       the [1mt [0mfunction, the verbose option gives more
	       information about the tape entries than just their
	       names.

     [1mw	       [0m_T_a_r 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.

     [1mf	       [0m_T_a_r uses the next argument as the name of the
	       archive instead of /_d_e_v/_t_a_p_e.  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 -)

     [1mF	       [0mWith one [1mF [0margument specified, exclude all direc-
	       tories named _S_C_C_S or _R_C_S from _t_a_r_f_i_l_e.  With two
	       arguments, [1mFF[0m, exclude all directories named _S_C_C_S
	       and _R_C_S, all files with ._o as as their suffix, and
	       all files named _e_r_r_s, _c_o_r_e, and _a._o_u_t.

     [1mb	       [0m_T_a_r uses the next argument as the blocking factor



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TAR(1)		    UNIX Programmer's Manual		   TAR(1)



	       for tape records. The maximum is 20. The default
	       value depends on the version of tar used; in the
	       BSD version (/usr/bin/tar) it is 20; in the X/Open
	       version (/usr/5bin/tar) it is 1.  This option
	       should only be used with raw magnetic tape
	       archives (See [1mf [0mabove).	The block size is deter-
	       mined automatically when reading tapes (key
	       letters `x' and `t').

     [1ml	       [0mtells _t_a_r to complain if it cannot resolve all of
	       the links to the files dumped.  If this is not
	       specified, no error messages are printed.

     [1mm	       [0mtells _t_a_r not to restore the modification times.
	       The modification time will be the time of extrac-
	       tion.

     [1mh	       [0mForce _t_a_r to follow symbolic links as if they were
	       normal files or directories.  Normally, _t_a_r does
	       not follow symbolic links.

     [1mB	       [0mForces input and output blocking to 20 blocks per
	       record.	This option was added so that _t_a_r can
	       work across a communications channel where the
	       blocking may not be maintained.

     [1mC	       [0mIf a file name is preceded by [1m-C[0m, then _t_a_r will
	       perform a _c_h_d_i_r(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
	       /usr/include and from /etc, one might use
		    tar c -C /usr include -C / etc

     Previous restrictions dealing with _t_a_r's inability to prop-
     erly handle blocked archives have been lifted.

[1mFILES
     [0m/dev/tape
     /dev/tape?
     /tmp/tar*

[1mSEE ALSO
     [0mtar(5)

[1mDIAGNOSTICS
     [0mComplaints 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)		    UNIX Programmer's Manual		   TAR(1)



[1mBUGS
     [0mThere is no way to ask for the _n-th occurrence of a file.
     Tape errors are handled ungracefully.
     The [1mu [0moption 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 [1mr [0mor [1mu [0moptions,
     directory modification times may not be set correctly.

     _t_a_r will create `holes' in the output files for completely
     zero disc blocks, this saves considerable disc space on
     RISC iX systems. Some NFS fileservers (eg those running
     4.2BSD) have a bug which cause them to add a zero byte to
     files copied in this manner.  This can be avoided by using
     _t_a_r_0 which is identical to _t_a_r except that it copies the
     files byte for byte.







































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