Update a submodule to the latest commit

Question

I have a project A which is a library and it is used in a project B.

Both projects A and B have a separate repository on github BUT inside B we have a submodule of A

Answer 1

None of the above answers worked for me.

This was the solution, from the parent directory run:

git submodule update --init;
cd submodule-directory;
git pull;
cd ..;
git add submodule-directory;

now you can git commit and git push

Answer 2

Andy's response worked for me by escaping $path:

git submodule foreach "(git checkout master; git pull; cd ..; git add \$path; git commit -m 'Submodule Sync')"