What do the following terms mean? SaaS PaaS IaaS? There are various cloud services available today, such as Amazon's EC2 and AWS, Apache Hadoop, Microsoft Azure and many others. Which category doe... See also: What is the meaning of $? (dollar question mark) in shell scripts? Regular expression There are two types: BRE (Basic) and ERE (Extended). Basic is deprecated and only kept to not break APIs. Those are implemented by C API functions, and used throughout CLI utilities, e.g. grep accepts BREs by default, and EREs with -E. In github, I often see these terms and in many cases they are used interchangeably. Can someone please explain the difference between a contributor and a collaborator? I'd like to know the differences between doing a Fork of a project and doing a clone of it. Can I only send pull requests via GitHub if I've forked a project?
