No, I did not just sneeze at you. These are the names of the commands you should get to know if you're a bleeding edge Flex developer.

In a nutshell:

To get more advanced, specify the path to output the compiled swf to, and mark for debug:

But mxmlc is slow. So use fcsh instead. It's wayyy faster, since it keeps objects in memory. Incremental compilation is definitely the way to go here.

And to debug at the command line, fdb is really cool. Check it out!

All of these executables are in the sdks/SDK-NAME/bin folder of your Flex Builder Install, btw