Steps to break one large repo into multiple repos based off of DIRNAME
git filter-branch --prune-empty --subdirectory-filter DIRNAME master
rm -rf .git/refs/original/ && git reflog expire --all && git gc --aggressive --prune=now
git clean -fdx
git reflog expire --all --expire-unreachable=0
git repack -A -d
git prune
git remote rm origin