Question on git-filter-branch

[Bill Lear <rael@zopyra.com>]

In my repo, I have sensitive files A, C, and a directory full of
sensitive stuff I want to remove forever from the git repository.

% ls
A B C D sensitive_stuff

% git --version
git version 1.5.3.5

% git filter-branch --index-filter 'git update-index --remove A' HEAD
Rewrite 5dd7d5f2d7d3a5f43c242188ac96294628267673 (7/7)
Ref 'refs/heads/master' was rewritten

These refs were rewritten:
% ls
B  C  D  sensitive_stuff

% git status
# On branch master
nothing to commit (working directory clean)

Ok, so I guess it has done what I wanted.  So, I try to remove the
next file that has sensitive information in it:

% git filter-branch --index-filter 'git update-index --remove C' HEAD
Namespace refs/original/ not empty

And there I am stuck: what do I do now?

I did also try this (on a fresh clone of the original repo):

% git filter-branch --index-filter 'git update-index --remove A C sensitive_stuff/*' HEAD
Rewrite 5dd7d5f2d7d3a5f43c242188ac96294628267673 (7/7)
Ref 'refs/heads/master' was rewritten

These refs were rewritten:
% ls
B  D  sensitive_stuff/
% ls sensitive_stuff
E  F  G

So, that appears to have removed A and C, but it did nothing to the
files in the subdirectory.  Is there a way to remove the files in the
subdirectory --- or, better, to simply remove the entire subdirectory?

I did try reading the man page for this, and the first example is
essentially what I want.  It says "you will get the rewritten history
saved in HEAD", but I'm not sure what I'm supposed to do next.


Bill