How do I cd to the closest parent folder that has a .git folder with bash?

When working on projects that are version controlled I often end up in a nested folder. Using cd ../../ gets a bit cumbersome, so I was wondering if there is a way to define an alias in bash that cd's to the parent until it reaches a folder with a .git folder, or it reaches ~.

So let's say that

~/my-project is a git repository
my cwd is ~/my-project/deeply/nested/folder/structure
I run the command and am cd'ed to ~/my-project

What command could do this? Would I need a bash function?

Solution

The command you're looking for is git rev-parse --show-toplevel, you can make a bash function that uses it.

gr() {
    cd "$(git rev-parse --show-toplevel)"
}

I also have in my ~/.gitconfig:

[alias]
    root = rev-parse --show-toplevel

Which makes this command a little more reasonable looking.