Remove a folder from git tracking

I came across this question while Googling for "git remove folder from tracking". The OP's question lead me to the answer. I am summarizing it here for future generations.

Question

How do I remove a folder from my git repository without deleting it from my local machine (i.e., development environment)?

Answer

Step 1. Add the folder path to your repo's root .gitignore file.

path_to_your_folder/

Step 2. Remove the folder from your local git tracking, but keep it on your disk.

git rm -r --cached path_to_your_folder/

Step 3. Push your changes to your git repo.

The folder will be considered "deleted" from Git's point of view (i.e. they are in past history, but not in the latest commit, and people pulling from this repo will get the files removed from their trees), but stay on your working directory because you've used --cached.

This works for me:

git rm -r --cached --ignore-unmatch folder_name

--ignore-unmatch is important here, without that option git will exit with error on the first file not in the index.