TAR(1) TAR(1) NAME tar - tape archiver SYNOPSIS tar [ key ] [ name ... ] DESCRIPTION _T_a_r saves and restores multiple files on a single file (usually a mag‐ netic 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 possibly 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: 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 mes‐ sage of the form "/: cannot create". This modifier will suppress the directory information. p This modifier says to restore files to their original modes, ignoring the present _u_m_a_s_k(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 nor‐ mally /dev/rmt8. v Normally _t_a_r does its work silently. The v (verbose) option makes _t_a_r 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 _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. f _T_a_r uses 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, _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 _T_a_r 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 _t_a_r to complain if it cannot resolve all of the links to the files dumped. If this is not specified, no error mes‐ sages are printed. m tells _t_a_r not to restore the modification times. The modifi‐ cation time will be the time of extraction. h Force _t_a_r to follow symbolic links as if they were normal files or directories. Normally, _t_a_r does not follow symbolic links. B Forces input and output blocking to 20 blocks per record. This option was added so that _t_a_r can work across a communi‐ cations channel where the blocking may not be maintained. C If a file name is preceded by -C, 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 properly handle blocked archives have been lifted. FILES /dev/rmt? /tmp/tar* SEE ALSO tar(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 modi‐ fication times may not be set correctly. 7th Edition May 12, 1986 TAR(1)