It's possible to work from the command line after and only after generating the synthesis and place and route of the programmable logic.
The only FOSS project capable of doing those steps (i think) is Yosys, but somebody have to integrate PSoC support for that, i don't know if it will be available on the near time frame tho, i hope i'm wrong and somebody is already working on that .
any leads on how to set things up?
i.e. Tools for the build & flash procedures
Creator can generate Makefiles based on the settings of the project, you can generate them and use it from the command line,
Check the PSoC Creator documentation.
Remember you still need Windows-only tools for the sinthesis and place and route.
Ping team cypress. How about a Github repo for the new PSoC 6 to allow terminal only compile & flash from win/macos/linux. This would be much appreciated.