I have used Zephyr RTOS on the FRDM-K64F board mainly using the command line. Is it possible to use MCUXpresso IDE to create a Zephyr project? I am using Ubuntu 16.04.
You can generate an Eclipse project from cmake. This step needs to happen from the command line, but after that you can edit, build, and debug from Eclipse.
Here are some relevant links:
Application Development Primer — Zephyr Project Documentation
Zephyr Project using Eclipse