Deploy Jekyll build (_site) to github pages (assumes you're using master branch rather than gh-pages)

git-jekyll-deploy

#!/bin/sh

# To use:
#  1. save this file as /usr/bin-git-jekyll-deploy then `sudo chmod 775 /usr/bin/git-jekyll-deploy`
#  2. create a "source" branch where you'll maintain your jekyll site: git branch -b source
#  3. run `jekyll build`
#  4. run `git add . && git commit -am "update content"`
git branch -D master
git checkout -b master
git checkout source
git push origin `git subtree split --prefix _site master`:master --force