(tar)Mixing Styles

Old Options

Option Styles

Mixing Option Styles
--------------------

   All three styles may be intermixed in a single `tar' command, as
long as the rules for each style are fully respected.

   In GNU `tar' up to 1.11.6, using old style options was cutting out
the possibility of using many options not having short forms.  Many
users rightly expressed their frustration at fighting with the current
`tar' option decoder, so I changed it.  However, GNU `tar' needs to be
compatible with other `tar's, in the things that other `tar's can do.
Short options should provide upward compatibility.  So, if the current
option decoding raises incompatibilities, please let me know.

   Old style options and modern options may be mixed on a single call
to the `tar' program.  However, old style options should be introduced
in the first argument only; modern options may be given only after all
arguments to old style options have been collected.  If this rule is
not respected, a modern option might be falsely interpreted as the
value of the argument to one of the old style options.

   For example, currently, all the following commands are wholly
equivalent, and illustrate many combinations and orderings of option
styles.

     tar --create --file=archive.tar
     tar --create -f archive.tar
     tar --create -farchive.tar
     tar --file=archive.tar --create
     tar --file=archive.tar -c
     tar -c --file=archive.tar
     tar -c -f archive.tar
     tar -c -farchive.tar
     tar -cf archive.tar
     tar -cfarchive.tar
     tar -f archive.tar --create
     tar -f archive.tar -c
     tar -farchive.tar --create
     tar -farchive.tar -c
     tar c --file=archive.tar
     tar c -f archive.tar
     tar c -farchive.tar
     tar cf archive.tar
     tar f archive.tar --create
     tar f archive.tar -c
     tar fc archive.tar

   On the other hand, the following commands are *not* equivalent to
the previous set:

     tar -f -c archive.tar
     tar -fc archive.tar
     tar -fcarchive.tar
     tar -farchive.tarc
     tar cfarchive.tar

These last examples mean something completely different of what the user
might have intended.  The first four specify that the `tar' archive
would be a file named `-c', `c', `carchive.tar' or `archive.tarc',
respectively.  The first two examples also specify a single non-option,
NAME argument having value `archive.tar'.  The last example contains
only old style option letters (repeating option `c' twice) and no
argument value.