Clear already committed files but included in .gitignore

Sometimes it happens that a file was being tracked by git, but in a later point in time was added to .gitignore, in order to stop tracking it. It’s a very common scenario to forget to clean up such files before its addition to .gitignore. In this case, the old file will still be hanging around in the repository.

To fix this problem, one could perform a “dry-run” removal of everything in the repository, followed by re-adding all the files back. As long as you don’t have pending changes and the --cached parameter is passed, this command is fairly safe to run:

# Remove everything from the index (the files will stay in the file system) 
$ git rm -r --cached .

# Re-add everything (they'll be added in the current state, changes included)
$ git add .

# Commit, if anything changed. You should see only deletions
$ git commit -m 'Remove all files that are in the .gitignore'

# Update the remote
$ git push origin master