Git Submodules

Git submodules let you include one Git repository inside another as a subdirectory.

This is useful for adding libraries or dependencies managed in separate repositories, while keeping their commit history separate.

Submodules are helpful when you want to:

• Reuse code from another project
• Track a library or dependency at a specific commit
• Keep histories of projects separate

To add a submodule to your project, use:

This creates a subdirectory libs/library and updates .gitmodules with the submodule info.

When you clone a repository with submodules, you need to fetch their contents separately:

Or do it all at once when cloning:

To see the current commit and state of your submodules, use:

You can run a command in every submodule. For example, to check their status:

To update submodules to the latest commit from their remote repository:

The .gitmodules file keeps track of all submodules and their paths. Edit this file if you move or remove submodules.

• If submodules are empty after cloning, run git submodule update --init --recursive .
• If you change a submodule's URL, update both .gitmodules and .git/config .
• Submodules always point to a specific commit, not always the latest-remember to update if you want new changes.
• Keep submodules for external projects you want to track at a fixed version. For simpler needs, consider alternatives like Git subtree or copying files.

Only use them if you really need to track another project at a specific commit.