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(tar.info)Mnemonic Options

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Mnemonic Option Style
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   Each option has at least one long (or mnemonic) name starting with
two dashes in a row, e.g. `--list'.  The long names are more clear than
their corresponding short or old names.  It sometimes happens that a
single mnemonic option has many different different names which are
synonymous, such as `--compare' and `--diff'.  In addition, long option
names can be given unique abbreviations.  For example, `--cre' can be
used in place of `--create' because there is no other mnemonic option
which begins with `cre'.  (One way to find this out is by trying it and
seeing what happens; if a particular abbreviation could represent more
than one option, `tar' will tell you that that abbreviation is
ambiguous and you'll know that that abbreviation won't work.  You may
also choose to run `tar --help' to see a list of options.  Be aware
that if you run `tar' with a unique abbreviation for the long name of
an option you didn't want to use, you are stuck; `tar' will perform the
command as ordered.)

   Mnemonic options are meant to be obvious and easy to remember, and
their meanings are generally easier to discern than those of their
corresponding short options (see below).  For example:

     $ tar --create --verbose --blocking-factor=20 --file=/dev/rmt0

gives a fairly good set of hints about what the command does, even for
those not fully acquainted with `tar'.

   Mnemonic options which require arguments take those arguments
immediately following the option name; they are introduced by an equal
sign.  For example, the `--file' option (which tells the name of the
`tar' archive) is given a file such as `archive.tar' as argument by
using the notation `--file=archive.tar' for the mnemonic option.