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(tar.info)using tar options

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Using `tar' Options
===================

   GNU `tar' has a total of eight operating modes which allow you to
perform a variety of tasks.  You are required to choose one operating
mode each time you employ the `tar' program by specifying one, and only
one operation as an argument to the `tar' command (two lists of four
operations each may be found at Note: frequent operations and Note:
Operations).  Depending on circumstances, you may also wish to
customize how the chosen operating mode behaves.  For example, you may
wish to change the way the output looks, or the format of the files that
you wish to archive may require you to do something special in order to
make the archive look right.

   You can customize and control `tar''s performance by running `tar'
with one or more options (such as `--verbose' (`-v'), which we used in
the tutorial).  As we said in the tutorial, "options" are arguments to
`tar' which are (as their name suggests) optional.  Depending on the
operating mode, you may specify one or more options.  Different options
will have different effects, but in general they all change details of
the operation, such as archive format, archive name, or level of user
interaction.  Some options make sense with all operating modes, while
others are meaningful only with particular modes.  You will likely use
some options frequently, while you will only use others infrequently,
or not at all.  (A full list of options is available in Note: All
Options.)

   The `TAR_OPTIONS' environment variable specifies default options to
be placed in front of any explicit options.  For example, if
`TAR_OPTIONS' is `-v --unlink-first', `tar' behaves as if the two
options `-v' and `--unlink-first' had been specified before any
explicit options.  Option specifications are separated by whitespace.
A backslash escapes the next character, so it can be used to specify an
option containing whitespace or a backslash.

   Note that `tar' options are case sensitive.  For example, the
options `-T' and `-t' are different; the first requires an argument for
stating the name of a file providing a list of NAMEs, while the second
does not require an argument and is another way to write `--list'
(`-t').

   In addition to the eight operations, there are many options to
`tar', and three different styles for writing both: long (mnemonic)
form, short form, and old style.  These styles are discussed below.
Both the options and the operations can be written in any of these three
styles.