branchToRepo.sh

git clone <git repository A url>
cd <git repository A directory>
git remote rm origin
git filter-branch --subdirectory-filter <directory 1> -- --all
git remote add origin <git repository B url>
git push --set-upstream origin master

git clone <git repository A url>
cd <git repository A directory>
git filter-branch --force --index-filter 'git rm --cached --ignore-unmatch <directory 1> -r' --prune-empty --tag-name-filter cat -- --all
git push origin master --force