Question

I would like to change the directory name of a Git submodule in my Git superproject.

Lets suppose I have the following entry in my .gitmodules file:

[submodule ".emacs.d/vimpulse"]  
path = .emacs.d/vimpulse  
url = git://gitorious.org/vimpulse/vimpulse.git

What do I have to type to move the .emacs.d/vimpulse directory to .emacs.d/vendor/vimpulse without deleting it first (explained
here and here) and then re-adding it.

Does Git really need the whole path in the submodule tag

[submodule ".emacs.d/vimpulse"]

or is it also possible to store just the name of the subproject?

[submodule "vimpulse"]

Answer 1

Newer versions of git

Git now has native support for moving submodules:

Since git 1.8.5, git mv old/submod new/submod works as expected and does all the plumbing for you. You might want to use git 1.9.3 or newer, because it includes fixes for submodule moving.

Older versions of git

As mentioned in the comments, this answer refers to the steps needed with older versions of git.

The process is similar to how you’d remove a submodule (see How do I remove a submodule?):

1. Edit .gitmodules and change the path of the submodule appropriately, and put it in the index with git add .gitmodules.

2. If needed, create the parent directory of the new location of the submodule (mkdir -p new/parent).

3. Move all content from the old to the new directory (mv -vi old/parent/submodule new/parent/submodule).

4. Make sure Git tracks this directory (git add new/parent).

5. Remove the old directory with git rm --cached old/parent/submodule.

6. Move the directory .git/modules/old/parent/submodule with all its content to .git/modules/new/parent/submodule.

7. Edit the .git/modules/new/parent/config file, make sure that worktree item points to the new locations, so in this example it should be worktree = ../../../../../new/parent/module. Typically there should be two more .. than directories in the direct path in that place.

8. Edit the file new/parent/module/.git, make sure that the path in it points to the correct new location inside the main project .git folder, so in this example gitdir: ../../../.git/modules/new/parent/submodule.

   git status output looks like this for me afterwards:

    # On branch master
    # Changes to be committed:
    #   (use "git reset HEAD <file>..." to unstage)
    #
    #       modified:   .gitmodules
    #       renamed:    old/parent/submodule -> new/parent/submodule
    #
   

9. Finally, commit the changes.