Splitting a subpath out into a new repo
From time to time you may find that you want to make a new repo from a subpath of an existing repo. Perhaps you’re moving some code out into a library or just want to have a common submodule across projects. Thanks to git, it’s easy to do this without losing the history of that subpath in the process.
The Good Stuff
Splitting a subpath into a repo is a fairly straightforward process, even if the command is hard to remember. For this example, we split lib/ out of the GitHub gem repo, removing empty commits but retaining the path’s history.
[tekkub@tekBook: ~/tmp] $ git clone git://github.com/defunkt/github-gem.git Initialized empty Git repository in /Users/tekkub/tmp/github-gem/.git/ remote: Counting objects: 1301, done. remote: Compressing objects: 100% (769/769), done. remote: Total 1301 (delta 724), reused 910 (delta 522) Receiving objects: 100% (1301/1301), 164.39 KiB | 274 KiB/s, done. Resolving deltas: 100% (724/724), done. [tekkub@tekBook: ~/tmp] $ cd github-gem/ [tekkub@tekBook: ~/tmp/github-gem master] $ git filter-branch --prune-empty --subdirectory-filter lib master Rewrite 48dc599c80e20527ed902928085e7861e6b3cbe6 (89/89) Ref 'refs/heads/master' was rewritten
Now we have a re-written master branch that contains the files that were in lib/. We can simply add a remote to the new repo and push, or do whatever we want with the repo.