How to create patch with git for a new release of ebuild

cd /var/calculate/remote/distfiles/egit-src/mono.git
https://git-scm.com/docs/git-diff
git diff HEAD^ HEAD >/var/lib/layman/dotnet/dev-lang/mono/files/2710.patch
Compare the version before the last commit and the last commit

How to delete several commits from a branch?
http://stackoverflow.com/questions/1338728/delete-commits-from-a-branch-in-git
git rebase -i HEAD~6
The ~6 means rebase the last 6 commits.

http://stackoverflow.com/questions/6658313/generate-a-git-patch-for-a-specific-commit