Remove .DS_Store Files From A Git Repository

Remove existing files from the repository:

find . -name .DS_Store -print0 | xargs -0 git rm -f --ignore-unmatch

Add the line .DS_Store to the file .gitignore, which can be found at the top level of your repository (or created if it isn’t there already). Then

git add .gitignore
git commit -m '.DS_Store banished!'

Source: http://stackoverflow.com/questions/107701/how-can-i-remove-ds-store-files-from-a-git-repository