I believe that on Linux and OSX you can use system.debuglog. Windows, on the other hand, doesn't have the same concept of a single "command prompt" that you can access. cmd.exe is just another windows application. You can have several running at the same time.
What are you trying to accomplish? That would help steer the responses you will get.
Basically, once the user has entered data / modified values, I want the app to send those values to the Command Line and execute them.. This app is a GUI for a Command Line App, if that helps.