I accidently added lot of temporary files using
git add -A
git ls-files -z | xargs -0 rm -f
git diff --name-only --diff-filter=D -z | xargs -0 git rm --cached
git help rm
Do NOT run "git reset --hard". It will not only unstage your added files, but will revert any changes you made in your working directory. If you created any new files in working directory, it'll not delete them though.
If all you want is to undo an overzealous "git add" run:
Your changes will be unstanged and ready for you to re-add as you please.