Programmatically get path to git directory in bash (including submodules)

Question

Is it possible to programmatically find the path to the .git directory including for submodules?

I'm trying to write a script that installs a git hook but I can't find a straightforward way to find the .git directory for the project. Ideally it should cover the following cases:

1. In root directory of project
2. In sub-directory of project
3. In root directory of submodule within project
4. In sub-directory of submodule within project

I could do all of this manually but I'd rather not parse the .git file of a submodule.

Edit: I'd be interested in a solution in python as well.

Answer 1

git rev-parse --git-dir seems to be what you want. I just tested it with a submodule:

cd mymodule
git rev-parse --git-dir  # --> .git
git submodule add ssh://.../path/to/mysubmodule
cd mysubmodule
git rev-parse --git-dir  # --> /home/.../mymodule/.git/modules/mysubmodule

This surprised me, since there was a .git in mysubmodule, but it turned out to be a file, with the following contents:

gitdir: ../.git/modules/mysubmodule