Git command line - know if in submodule?

Question

Is there any way in git to know if you're in a submodule? You can do thinks like git submodule foreach in the parent directory but I can't seem to come up with a generic way to show that you're in a submodule if you're in one, or in any of the child directories inside the submodule.

I guess you could find the repo root with git rev-parse --show-toplevel, and then cd-ing up a level, and finding the root of that repo again and then comparing the list of submodules to the current directory, but that seems so sticky...

Answer 1

(Update April 2017 for Git 2.13, Q2 2017)

There is now an official command to determine if a repo is a submodule of a parent repo:

cd /path/to/potential/submodule/repo git rev-parse --show-superproject-working-tree 

See commit bf0231c (08 Mar 2017) by Stefan Beller (stefanbeller).
^{(Merged by Junio C Hamano -- gitster -- in commit 3edcc04, 17 Mar 2017)}

rev-parse: add --show-superproject-working-tree

In some situations it is useful to know if the given repository is a submodule of another repository.

Add the flag --show-superproject-working-tree to git-rev-parse to make it easy to find out if there is a superproject.
When no superproject exists, the output will be empty.

Jethro Yu suggests in the comments:

get super project path regardless inside/outside of submodule:

git rev-parse --show-superproject-working-tree --show-toplevel | head -1 

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(Update 2014) As noted by Quentin Pradet, more recent Git submodule repos show a simple .git file instead of a .git folder.
That .git file reference the path of the actual submodule git repo, stored in the parent repo .git/modules subfolder.

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(Original answer: Sept. 2011)

The very nature of a submodule is for the git repo acting as submodule has no idea it is used as a submodule by a parent repo.

One dirty trick would be to:

• change a file
• go back one level above the current repo
• try a "git status --ignore-submodules=none"
• restore the changed file.

If you see the file in the result of the git status, your repo should be a submodule.
If it is only a nested repo, the git status should ignore your nested repo entirely.