Untrack all files that already added to a repository

• Optionally, commit any code changes
• Add file/folder that you want to ignore to .gitignore file
• Then run the following command:

git rm -r --cached .

This removes any changed files from the index(staging area).

• Explain rm command

  • rm is the remove command
  • -r will allow recursive removal
  • –cached will only remove files from the index. Your files will still be there.
  • The . indicates that all files will be untracked. You can untrack a specific file with git rm --cached foo.txt.
  • The rm command can be unforgiving. If you wish to try what it does beforehand, add the -n or --dry-run flag to test things out.

• Then run:

git add .

This add all changes files to a staging area.

• Verify what you have changed.

git log

This will show all ignored file are mark as deleted

• Create a new commit:

git commit -m ".gitignore is now working"

credit https://www.codeblocq.com/2016/01/Untrack-files-already-added-to-git-repository-based-on-gitignore/