version control - Git repository inside another git repository

Question

I have the following directories structure:

• g1/
  • .git
  • a
  • b
  • c/
    • .git
    • d
    • e

As you can see, I have de repository "c" inside repository "g1". When I use the following command:

git clone g1 g2

I only get the following directories structure:

• g1/
  • .git
  • a
  • b
  • c/

The directory "c" remains empty. Any ideas?

Answer 1

Submodules (discussed in the Pro Git Book), helps manage repositories nested within a main repository:

Submodules allow foreign repositories to be embedded within a dedicated subdirectory of the source tree, always pointed at a particular commit.

They are not to be confused with remotes, which are meant mainly for branches of the same project; submodules are meant for different projects you would like to make part of your source tree, while the history of the two projects still stays completely independent and you cannot modify the contents of the submodule from within the main project.

Submodules maintain their own identity; the submodule support just stores the submodule repository location and commit ID, so other developers who clone the superproject can easily clone all the submodules at the same revision.