Aside from the GUI Exchange 2010 gives you two ways to assign client permissions — the permissions that dictate what end-users or clients can do — to Public Folders. One is a Powershell command that will apply permissions to a single folder. The other is a Powershell script that will apply permissions to a single folder and all subfolders.
Command to add client permission to single folder:
Powershell script to add client permissions to folder and below:
Note: The Shell doesn’t load scripts automatically. You must precede all scripts with .\ (a period, followed by a backslash). For example, to run the AggregatePFData.ps1 script, type .\AggregatePFData.ps1.
The collection of Shell scripts described in this topic is installed, by default, at <Exchange Installation Path>\v14\Server\Scripts.
See TechNet for more information
NOTE: You may need to change path to location of scripts in Powershell. When I tried adding location of scripts to PATH variable in a command prompt it did not work. Click on image to see what I mean.