Linux operating system is famous for command line interface and being an open-source. I don't consider it very user friendly but not all end users know how to enter commands. This was my first impression of Linux OS
Now there is phone being released with Linux touch called Pinephone. Its only and interface of Linux with GUI, not just CLI which makes more sense. This is still in experimental phase.
This phone will have all modern features like quad core processor, 16 GB ram, LTE network capability and all other basic features.
You can do endless customization with this phone, just like you can do with Android phones, which is a plus. I am not expecting this phone to be very expensive but we still have to see how it turns out.