git submodule - should not have been updated. How to back down

Question

When using "git submodule" I get myself into a new problem I have .gitmodules file within my git project "mainproject"

[submodule "subsystem1"]
  path = subsystem11
  url = /mnt/gitrepos/subsystem1.git/

Starting in my main project I did

$ cd subsystem1
$ git pull origin master

Lets assume that something is really wrong now in "submodule1". I got many updates in, that I did not like to have (right now).

$ cd .. #back in "mainproject"
$ git status  
# On branch master
# Your branch is behind 'origin/master' by 1 commit, and can be fast-forwarded.
#
# 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:   subsystem1 (new commits)
#
no changes added to commit (use "git add" and/or "git commit -a")

How can I revert to the version of subsystem1 that I had before pulling?

Answer 1

Since you haven't committed the changes to the submodule in your main project, git submodule update from the parent repo will revert the submodule to its previous state.