Git Submodules
In this page:
Adding a Submodule
A submodule embeds another Git repository as a subdirectory of your project, pinned to one specific commit rather than tracking a branch. This is the standard way to depend on a separate shared library's exact history without merging its commits into your own repository.
Example: Adding a Submodule
git submodule add https://github.com/user/library.git libs/libraryCloning Repositories with Submodules
When you git clone a project containing submodules, Git creates the submodule directories but leaves them empty — the parent repo only stores a pointer to which commit each submodule should be at. You must run git submodule init and git submodule update (or clone with --recurse-submodules) to actually populate them.
Example: Cloning Repositories with Submodules
git clone --recurse-submodules https://github.com/user/repo.git
git submodule update --init --recursiveUpdating Submodule Code
git submodule update --remote fetches the latest commits from each submodule's own remote and moves your local checkout forward to match, but it does NOT automatically update the parent repository's pinned pointer — you still need to git add and commit that pointer change yourself.
Example: Updating Submodule Code
git submodule update --remote
git add libs/library
git commit -m "Update submodule"Running Submodule Commands
git submodule foreach '<command>' runs an arbitrary shell command inside every registered submodule directory in sequence, saving you from manually cd-ing into each one — useful for something like running git status across all of them at once.
Example: Running Submodule Commands
git submodule foreach 'git status'Deleting a Submodule
Removing a submodule cleanly takes more than deleting its folder: you need to remove its entry from .gitmodules and .git/config, then run git rm --cached <path> to untrack it, and finally delete the leftover .git/modules/<path> cache directory — skipping any of these steps leaves stale references behind.
Example: Deleting a Submodule
git rm --cached libs/library
rm -rf .git/modules/libs/libraryChapter Quiz — Complete all 7 topics to unlock
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