git submodules - How can I move a single directory from a git repository to a new repository whilst maintaining the history?

Question

I have inherited a git repository containing multiple projects in separate directories. I'd like to split the repository into new individual repositories, one for each project and then have the master repository contain the projects as submodules. I'd like to do all this whilst maintaining the revision history of the individual projects if possible.

I could clone the repository for each project and remove all the other projects each time, but it there a better way to avoid having the cloned history in each new project repository?

Answer 1

You can use git filter-branch to rewrite the history of a project. From the documentation:

To rewrite the repository to look as if foodir/ had been its project root, and discard all other history:

git filter-branch --subdirectory-filter foodir -- --all

Make several copies of your repo, do that for each subdirectory you want to split out, and you should wind up with what you're looking for.