Removing a File from All past Git Commits

I have a tendency not to add .DS_Store to my .gitignore until I’ve already pushed to Github. Every single goddamn time it happens, I have to spend ten minutes googling for the answer.

Well, here be dragons:

git filter-branch --index-filter 'git rm --cached --ignore-unmatch .DS_Store' HEAD

• The filter-branch command rewrites commit history based on the filter that you provide.
• The --index-filter tells git to rewrite the index — it doesn’t check out the tree, which is apparently faster.
• The filter we’re passing tells git to remove the .DS_Store from the staging area and delete it’s paths from the index — aka --cached.
• The ignore-unmatch flag does exactly that, the remove command exits with a 0 status even if no matches were found.

May the git lords have pity on your soul.