How to Ignore new commits for git submodule

the git occured serveral new commits like:

Changes not staged for commit:
(use "git add <file>..." to update what will be committed)
(use "git checkout -- <file>..." to discard changes in working directory)

modified:   bbi (new commits)
modified:   bbif (new commits)
modified:   c2c (new commits)
modified:   e6 (new commits)
modified:   nodetestif (new commits)

and I don’t know how it comes and the git clean -xdf,git checkout .,git checkout – are all don’t work.

So how to fix it?

Just run:

$ git submodule update

This will revert the submodule the to old commit (specified in parent-repo), without updating the parent-repo with the latest version of the submodule.