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(tar.info)What tar Does

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What `tar' Does
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   The `tar' program provides the ability to create `tar' archives, as
well as various other kinds of manipulation.  For example, you can use
`tar' on previously created archives to extract files, to store
additional files, or to update or list files which were already stored.

   Initially, `tar' archives were used to store files conveniently on
magnetic tape.  The name `tar' comes from this use; it stands for
`t'ape `ar'chiver.  Despite the utility's name, `tar' can direct its
output to available devices, files, or other programs (using pipes).
`tar' may even access remote devices or files (as archives).

   You can use `tar' archives in many ways.  We want to stress a few of
them: storage, backup, and transportation.

Storage
     Often, `tar' archives are used to store related files for
     convenient file transfer over a network.  For example, the GNU
     Project distributes its software bundled into `tar' archives, so
     that all the files relating to a particular program (or set of
     related programs) can be transferred as a single unit.

     A magnetic tape can store several files in sequence.  However, the
     tape has no names for these files; it only knows their relative
     position on the tape.  One way to store several files on one tape
     and retain their names is by creating a `tar' archive.  Even when
     the basic transfer mechanism can keep track of names, as FTP can,
     the nuisance of handling multiple files, directories, and multiple
     links makes `tar' archives useful.

     Archive files are also used for long-term storage.  You can think
     of this as transportation from the present into the future.  (It
     is a science-fiction idiom that you can move through time as well
     as in space; the idea here is that `tar' can be used to move
     archives in all dimensions, even time!)

Backup
     Because the archive created by `tar' is capable of preserving file
     information and directory structure, `tar' is commonly used for
     performing full and incremental backups of disks.  A backup puts a
     collection of files (possibly pertaining to many users and
     projects) together on a disk or a tape.  This guards against
     accidental destruction of the information in those files.  GNU
     `tar' has special features that allow it to be used to make
     incremental and full dumps of all the files in a filesystem.

Transportation
     You can create an archive on one system, transfer it to another
     system, and extract the contents there.  This allows you to
     transport a group of files from one system to another.