How to remove files from git staging area?

Use

git reset

to unstage all the staged files.

You can unstage files from the index using

git reset HEAD -- path/to/file

Just like git add, you can unstage files recursively by directory and so forth, so to unstage everything at once, run this from the root directory of your repository:

git reset HEAD -- .

Also, for future reference, the output of git status will tell you the commands you need to run to move files from one state to another.

If you've already committed a bunch of unwanted files, you can unstage them and tell git to mark them as deleted (without actually deleting them) with

git rm --cached -r .

--cached tells it to remove the paths from staging and the index without removing the files themselves and -r operates on directories recursively. You can then git add any files that you want to keep tracking.

Now at v2.24.0 suggests

git restore --staged .

to unstage files.