How does the command line work in windows with exe files?

Question

cmd/bat

Can you tell me where to look for documentation on cmd ?
Interested in how exactly it works with exe files? The point is the following. I create an executable file with some packer, for example nsis. The output is "file name. exe".
If you rename this file to "filename.jigurda" and run it through the gui shell, then Windows will write that it does not know such a file extension and asks you to specify how to open such a file.
If you run this file through smd "file name.jigurda" then the exe quietly works out and starts. The same trick, for example, with a dock file or txt will not work.
So, I'm interested in what exactly smd does with the file? Is she parsing him? What is she looking for in him? Different packers have different syntax (for example, msi and nsis).

Answer 1

Yes, she parses him. No, the output syntax is the same - Win PE. She looks for the PE file headers in it.