git submodule update

The `git submodule update` command updates the submodules in a Git repository to the latest version of the submodule code that has been committed to the parent repository. It fetches the latest changes from the submodule's remote repository and checks out the appropriate commit in the parent repository.

If you have just cloned a repository with submodules or if a submodule has been added or updated in the parent repository since the last time you ran `git submodule update`, you will need to run the command to ensure that the submodule's code is up to date in your local repository.

The `git submodule update` command can take various options and arguments to control its behavior, such as specifying which submodule(s) to update or whether to initialize submodules that have not been initialized yet.