Finding the name of the parent branch?

[Pascal Obry <pascal@obry.net>]

I want to find the name of the parent branch in a script. What is the best way?

                         o---o---o---C
                         /
                    o---o---o---B
                   /
           ---o---o---o---o---o---A

For B I want to get A and for C I want to get B.

All this can be found in gitk, but from a script I did not found a
good solution.

Any idea?

Thanks.
Pascal.

-- 

--|------------------------------------------------------
--| Pascal Obry                           Team-Ada Member
--| 45, rue Gabriel Peri - 78114 Magny Les Hameaux FRANCE
--|------------------------------------------------------
--|              http://www.obry.net
--| "The best way to travel is by means of imagination"
--|
--| gpg --keyserver wwwkeys.pgp.net --recv-key C1082595