git pull --recurse-submodules
git submodule update --remote --recursive
#https://chrisjean.com/git-submodules-adding-using-removing-and-updating/
#it checks out the specific version of the project and respective submodule recursively (if applicable)
#but not within a branch.
git submodule update --init --recursive
#or
git submodule init && git submodule update --recursive
git submodule init
git submodule update
$ git submodule update --init --recursive
submodule@example:~$ git clone --recurse-submodules https://gitlab.com/cameronmcnz/surface.git
submodule@example:~$ cd sur*
submodule@example:~$ git submodule update --remote
submodule@example:~$ git add .
submodule@example:~$ git commit -m "git submodule updated"
submodule@example:~$ git push origin
cd projB/projA
git pull origin master
git pull
git submodule update --remote --merge