- Navigate to the project's include subdirectory
git submodule add git@github.com:rbeesley/plog.git plog
cd plog
git submodule update --init --recursive
- Navigate to the plog subdirectory
git submodule update --recursive
-or-
- From the root git project
git pull --recurse-submodules
Created following the article "How to Turn a Turn a Directory in a Git Repository Into a Submodule": https://www.howtogeek.com/devops/how-to-turn-a-turn-a-directory-in-a-git-repository-into-a-submodule/