Sometimes you'll want or have to split a git repository into two. This is usually a sign of not thinking forward enough but hey sh.. happens. If your repository is structured in a way that you just need a subdirectory of it into a new repository you can follow the steps below.
We assume a repository foo that contains a folder foobar that shall be a new repository called bar.
% git clone --no-hardlinks foo bar % cd bar % git filter-branch --subdirectory-filter foobar HEAD -- --all % git reset --hard % git gc --aggressive % git prune
If you're working with remote repositories you'll have to delete the old remote origin and set a new one.
% git remote rm origin % git remote add origin firstname.lastname@example.org:bar.git % git push -u origin master
Now we'll cleanup the original repository.
% cd foo % git filter-branch --tree-filter "rm -rf foobar" --prune-empty HEAD % rm -rf foobar % git push -f
Now you should now have two seperate repositories.