!PS:TAR-FOR-XXX.TXT.11, 22-Jan-90 14:38:05, Edit by BEEBE Tar for Other Operating Systems [22-Jan-1990] The UNIX tar (tape archive) utility is widely used on the Internet for collecting groups of files into a single archive file for intermachine transfer. Despite its name, tar is not limited to tapes, and today, is probably used far more with disks and pipes. Usually, files stored for Internet retrieval are also compressed; such compression can be recognized by the extension .tar.Z on UNIX, and .tarz on other systems. With the create option (tar c), tar takes a list of files, possibly containing directories, and writes those files to the archive, which may be the standard output, together with their owner and group numbers, protection bits, and time stamps. If the file is a directory, all the files in that directory are written to the archive. The only real restriction is that the complete path name of all files written must not exceed 100 characters in length. The support for directories and pipes means that one can transfer entire directory trees between UNIX systems on a TCP/IP network with a simple command like cd somedir; tar cf - . | rsh somemachine 'cd someotherdir; tar xf -' without ever having to store a copy of the entire archive. With the extract option (tar x), tar reverses the process, creating files with appropriate ownership, and the original protection bits and time stamps. With the type option (tar t), tar simply lists the contents of the archive. Implementations of tar are available for several operating systems. Most UNIX systems will already have tar, but a few smaller (or perhaps, older) ones do not; for them, I recommend getting the Free Software Foundation GNU tar implementation (available on prep.ai.mit.edu for anonymous ftp), which provides a superset of tar features, including the abilitity to use GNU tar for system backup and restore, and to compress or uncompress data during creation or extraction. For PC DOS, the directory IBMPC: on science.utah.edu has these files: DETAR.ARC TAR.ARC TARREAD.EXE For TOPS-20, there are several independent implementations, none of which is a panacea. I have most often used SYS:CUTAR2.EXE which handles line terminator conversion (when requested to do so with the "set eol" command"), and also permits the user to set the output file bytesize ("set bytesize n"), and to recognize TOPS-20 NFS filenames ("set nfs-name-translation"). However, it does not correctly recognize directory structure in a tar archive, and will write all of its output files into a single directory. To solve that problem, use the older SYS:TAR8.EXE SYS:TAR.HLP SYS:ASCIFY.EXE HLP:ASCIFY.HLP ASCIFY can be used after the fact to convert line terminators. For VAX VMS, there is a tar reader (it cannot make tar archives) available on ctrsci.math.utah.edu in VMS-TAR-VMS-4-4.BCK For VAX VMS Version 4.4 VMS-TAR.BCK For VAX VMS Version 5.x This version will handle conversion of line terminators, and usually can recognize binary files automatically. It has been used many times to transfer parts of the TeX tree from TOPS-20 to VAX VMS (the tree contains both binary and text files). Its command line options are a subset of those recognized by UNIX tar, with an additional one to permit selection of the output VMS file format.