You can reference issues between repositories by mentioning user/repository#number in an issue.
Use emoji in your commits
Issue references within a repository
Any number that refers to an Issue or Pull Request will be automatically converted into a link.
Learn Git Quickly
git - the simple guide One of the simplest and most straightforward guides
Git CheatSheet - I really like the layout on this page
Things I Needed to Learn About Git and Thought I Should Bookmark for the Future
git log --pretty=oneline
How to undo (almost) anything with Git
Sometimes you need to revert the last commit, or a mass undo. Here is a good list of how to undo stuff.
What happens when the repository owner has not prepared a zip file, and you just want a download to use yourself? There is an answer and you don't need to go though that horrid process to download software, install and register keys and whatnot on GitHub, etc.!
To simply download a repository as a zip file: add the extra path '/zipball/master/' to the end of the repository URL and voila, it gives you a zip file of the whole lot.
It then gives you a zip file to download.