What's the difference between various command shells in VS2010?
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What's the difference between "visual studio x64 win64 command prompt", "visual studio x64 cross tools command prompt", and "visual studio command prompt" appearing in the Visual Studio 2010 menu in the Start button?  

For the most useful answer, let us be clear about my ignorance level: I'm closer to noob than guru at anything Microsoft or IDEs in general.  Long time expert at Linux, editing source in a plain text editor, handmade Makefiles, etc.  

I'm sure the differences are simple, perhaps "obvious" to anyone with modest experience at VS2010.