How to Pull a Git Repository with Sub Modules

In some cases, we might need to add a sub-module to our Git repository. A sub-module is actually a pointer that points to another Git repository.

For example, we have the following repositories Master Repo, SubModule1, and SubModule2. We can add the 2 sub-modules inside the master repo as specified in the documentation here  https://git-scm.com/book/en/v2/Git-Tools-Submodules.

By default, if we clone the master repo it will not download the sub-modules. How do we do that?

// pull all the sub modules for the first time
git submodule update --init --recursive

// update the sub modules
git submodule update --recursive --remote

// How to add a new sub module?
git submodule add -b main git@github.com:czetsuya/ct-keycloak-plugins.git