Git: Книга от сообщества

See what files `git-submodule` created:

$ ls -a

. .. .git .gitmodules a b c d

The `git-submodule add` command does a couple of things:

- It clones the submodule under the current directory and by default checks out

the master branch.

- It adds the submodule's clone path to the linkgit:gitmodules[5] file and

adds this file to the index, ready to be committed.

- It adds the submodule's current commit ID to the index, ready to be

committed.

Commit the superproject:

$ git commit -m "Add submodules a, b, c and d."

Now clone the superproject:

$ cd ..

$ git clone super cloned

$ cd cloned

The submodule directories are there, but they're empty:

$ ls -a a

. ..

$ git submodule status

-d266b9873ad50488163457f025db7cdd9683d88b a

-e81d457da15309b4fef4249aba9b50187999670d b

-c1536a972b9affea0f16e0680ba87332dc059146 c

-d96249ff5d57de5de093e6baff9e0aafa5276a74 d

NOTE: The commit object names shown above would be different for you, but they

should match the HEAD commit object names of your repositories. You can check

it by running `git ls-remote ../git/a`.

Pulling down the submodules is a two-step process. First run `git submodule

init` to add the submodule repository URLs to `.git/config`:

$ git submodule init

Now use `git-submodule update` to clone the repositories and check out the

commits specified in the superproject:

$ git submodule update

$ cd a

$ ls -a

. .. .git a.txt

One major difference between `git-submodule update` and `git-submodule add` is

that `git-submodule update` checks out a specific commit, rather than the tip

of a branch. It's like checking out a tag: the head is detached, so you're not

working on a branch.

$ git branch

* (no branch)

master

If you want to make a change within a submodule and you have a detached head,

then you should create or checkout a branch, make your changes, publish the

change within the submodule, and then update the superproject to reference the

new commit:

$ git checkout master

or

$ git checkout -b fix-up

then

$ echo "adding a line again" >> a.txt

$ git commit -a -m "Updated the submodule from within the superproject."

$ git push

$ cd ..

$ git diff

diff --git a/a b/a

index d266b98..261dfac 160000

--- a/a