A software license (or software licence in commonwealth usage) is a legal instrument governing the usage or reistribution of copyright protected software. A typical software license grants an end-user permission to use one or more copies of software in ways where such a use would otherwise constitute infringement of the software publisher's exclusive rights under copyright law. In effect, the software license acts as a promise from the software publisher to not sue the end-user for engaging in activities that would normally be considered exclusive rights belonging to the software publisher.