referenced from official docs of octopress http://octopress.org/docs/blogging/

New Post

cd /path/to/octopress
rake new_post['title']
<edit /path/to/octopress/source/_post/YYYY-mm-dd-title.markdown>
rake generate
(if want to preview:
    rake watch
    rake preview (or use [pow](http://pow.cx/))
)
rake deploy

ps. Recommend Mou as markdown editor for OSX

Modify Anything Else

e.g. _config.yaml modified

rake generate
rake deploy

Git Push

git commit add …

git commit -m’…’

git push origin source