How do I remove a file from all branches in a git repository but leave it on the file system

Question

At some point I added a large file into a git repository. It now exists on multiple branches, possibly with some changes to it. I'd like to remove it from git, but leave its current form (say the one on the master branch) on the file system.

I tried (on a dummy git archive)

git filter-branch --index-filter 'git rm --cached --ignore-unmatch bigfile' master branch1 branch2

That, however, does not leave a copy of bigfile on the file system.It isn't clear to me why not, though the description of the --tree-filteroption to filter-branch (I'm using the --index-filter option, but is is "similar") states:" (new files are auto-added, disappeared files are auto-removed ... )".
Is there a direct way to do what I want, with git? I've found similar requests;none of the responses point out that the above command actually deletes the file from the file system.

Answer 1

You've figured out how to remove it from the repository. To keep a copy around, I would extract it explicitly with "git cat-file" and put it somewhere outside of the working copy before doing "git filter-branch".

Answer 2

If it is still in the working directory, why not rename it (using OS commands, not git command), do the git command to remove all traces as previously mentioned, then rename it back?