Compiling an IDEA project without running IDEA itself

This IDEA blog entry http://blog.jetbrains.com/scala/2012/12/28/a-new-way-to-compile/ states that a project can be compiled without running IDEA - how do I do that ?

From the blog entry:

     Now we can compile IDEA projects without running IDEA itself, e. g. from command line or from build tools (like Ant, Maven, etc.).

Thanks

-Rohit