如何在Golang中的软件包中构建二进制文件？

I have a project in github.com/user called project:

src/
    github.com/user/project
        sub1/
            main.go
            sub1.exe (??)
        sub2/
            main.go
            sub2.exe (??)

I am trying to compile the package in my project. When I:

$ cd github.com/user/project/sub1
$ go build

Nothing happens. go build seems to finish without complaining, but there is no executable file. How can I build packages into executable?

"go version go1.3 windows/amd64"

It doesn't matter if you name your file main.go or shubudoo.go. The only thing what matters if you want to build an executable (a command) is that your files start with package main. One more thing: Go has absolutely no notion of "subpackage": All packages are equal for the compiler. The filesystem nesting is for your convenience only.