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GNU tar

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3.5 GNU tar documentation

Being careful, the first thing is really checking that you are using GNU tar, indeed. The --version option will generate a message giving confirmation that you are using GNU tar, with the precise version of GNU tar you are using. tar identifies itself and prints the version number to the standard output, then immediately exits successfully, without doing anything else, ignoring all other options. For example, `tar --version' might return:

tar (GNU tar) 1.13

The first occurrence of `tar' in the result above is the program name in the package (for example, rmt is another program), while the second occurrence of `tar' is the name of the package itself, containing possibly many programs. The package is currently named `tar', after the name of the main program it contains(4).

Another thing you might want to do is checking the spelling or meaning of some particular tar option, without resorting to this manual, for once you have carefully read it. GNU tar has a short help feature, triggerable through the --help option. By using this option, tar will print a usage message listing all available options on standard output, then exit successfully, without doing anything else and ignoring all other options. Even if this is only a brief summary, it may be several screens long. So, if you are not using some kind of scrollable window, you might prefer to use something like:

$ tar --help | less

presuming, here, that you like using less for a pager. Other popular pagers are more and pg. If you know about some keyword which interests you and do not want to read all the --help output, another common idiom is doing:

tar --help | grep keyword

for getting only the pertinent lines.

The perceptive reader would have noticed some contradiction in the previous paragraphs. It is written that both --version and --help print something, and have all other options ignored. In fact, they cannot ignore each other, and one of them has to win. We do not specify which is stronger, here; experiment if you really wonder!

The short help output is quite succint, and you might have to get back to the full documentation for precise points. If you are reading this paragraph, you already have the tar manual in some form. This manual is available in printed form, as a kind of small book. It may printed out of the GNU tar distribution, provided you have TeX already installed somewhere, and a laser printer around. Just configure the distribution, execute the command `make dvi', then print `doc/tar.dvi' the usual way (contact your local guru to know how). If GNU tar has been conveniently installed at your place, this manual is also available in interactive, hypertextual form as an Info file. Just call `info tar' or, if you do not have the info program handy, use the Info reader provided within GNU Emacs, calling `tar' from the main Info menu.

There is currently no man page for GNU tar. If you observe such a man page on the system you are running, either it does not long to GNU tar, or it has not been produced by GNU. Currently, GNU tar documentation is provided in Texinfo format only, if we except, of course, the short result of tar --help.

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