Now when you want to run WinAVR (e.g. to continue the examples here), you can simply double-click on the winavr.bat file. This will configure the path for just that terminal, rather than every terminal you open.
Note if using WinAVR on Windows 8.1/10, you must replace the dll msys-1.0.dll with an updated version. See [http://www.avrfreaks.net/forum/windows-81-compilation-error Windows 8.1 Fix] for a link to this DLL replacement.