One command-line tool that is baked into every version of Microsoft Windows is GPUpdate. Based on the name, you can probably guess that this command has something to do with updating Group Policy settings. Think of GPUpdate as a client-side tool that allows you to initiate a new "pull" of Group Policy settings. When you create a new GPO or make changes to an existing GPO, those changes will roll around naturally without any manual user input, but that rollout happens on a schedule which could leave you waiting 90 minutes or more in order to test your new settings. GPUpdate is the tool that speeds up that process.

There are a number of switches that can be used alongside the gpupdate command, each serving different purposes. Before we discuss the different switches and their uses, it will be important to understand the two different ways that Group Policy processing happens on a machine.