SharePoint lists represent a securable object to which you can apply desired permissions. Items in your SharePoint lists can also have their distinct set of permissions. This allows you to limit the level of access individuals on the site will have when accessing lists and items in them.
In organizations restructuring their SharePoint site, quite often there is an immediate need to assign a new set of permissions to a multitude of items within the site. Using PowerShell, you can not only speed up the process, but also have a reference point in case you are required to make an adjustment or are rolling back your changes.
You are already familiar working with lists using PowerShell. For this recipe, we will use PowerGUI to author the script, which means you will need to be logged in with an administrator's role on the target Virtual Machine.