Some editors create temporary files and folders to keep track of a project (example: .idea for PyCharm), some OS create temporary files and folders for thumbnails (example: .DS_STORE on macs). While those files are probably useful for you, they don’t really relate to the git project you’re working on, but sometimes we end up adding them to the git repo by accident because we forgot to add a .gitignore file in the project.

But while a .gitignore can help keep those unnecessary files (for the project) out of the git repo, since those files aren’t related to the project at all, I don’t think they should be even in the .gitignore. If I use pycharm, and you use vim, why should a repo shared between should care what editors we use? What if we were working in a project with 10 developers and each of them had their own esoteric OS/editor combo that left files, do we keep track of them in the .gitignore? What if you now want to split that monolith into multiple services?

There's a solution to this, it’s the .gitignore_global file, you can keep this file anywhere you like and configure your .gitconfig to point to it. Here’s mine, you can use it for inspiration. You can now remove the .idea/.DS_STORE out of your projects .gitignore and next time someone adds them to your project’s .gitignore, nudge them to this article.