How do I remove a submodule?

Question

How do I remove a Git submodule?

By the way, is there a reason I can't simply do git submodule rm whatever ?

Answer 1

project dir:     ~/foo_project/
submodule:       ~/foo_project/lib/asubmodule
- - - - - - - - - - - - - - - - - - - - - - - - -
run:
  1.   cd ~/foo_project
  2.   git rm lib/asubmodule && 
          rm .git/modules/lib/asubmodule && 
            git submodule lib/asubmodule deinit --recursive --force

Answer 2

I just found the .submodule (forgot exact name) hidden file, it has a list... you can erase them individually that way. I just had one, so I deleted it. Simple, but it might mess up Git, since I don't know if anything's attached to the submodule. Seems ok so far, aside from libetpan's usual upgrade issue, but that's (hopefully) unrelated.

Noticed nobody posted manual erasing, so added

Answer 3

Just a note. Since git 1.8.5.2, two commands will do:

git rm the_submodule
rm -rf .git/modules/the_submodule

As @Mark Cheverton's answer correctly pointed out, if the second line isn't used, even if you removed the submodule for now, the remnant .git/modules/the_submodule folder will prevent the same submodule from being added back or replaced in the future. Also, as @VonC mentioned, git rm will do most of the job on a submodule.

--Update (07/05/2017)--

Just to clarify, the_submodule is the relative path of the submodule inside the project. For example, it's subdir/my_submodule if the submodule is inside a subdirectory subdir.

As pointed out correctly in the comments and other answers, the two commands (although functionally sufficient to remove a submodule), do leave a trace in the [submodule "the_submodule"] section of .git/config (as of July 2017), which can be removed using a third command:

git config -f .git/config --remove-section submodule.the_submodule 2> /dev/null