Pragmatic Guide to Git

8	Ignoring Files

Software projects generate a lot of cruft. Some of it you don’t need to commit. For example, I do a lot of work in Python, which leaves a ton of .pyc files laying around, and I edit using MacVim, which creates a swap file for each file that you’re editing. We don’t need or want these files cluttering up our repository or showing up in git status. That’s where the .gitignore and friends comes in.

Each line of the .gitignore is scanned, and any matches it finds are ignored by Git. Your .gitignore file is inside your repository, so you can track it like any other file. You can put it at the top level of your repository, and in that case the rules cascade through all subdirectories. You can also use subdirectory-specific ...