This is my story on getting a Feather Huzzah32 up and programmable on my Ubuntu 18.04 computer, in case someone finds it and finds the information useful.

Here is a link to Adafruit's learning guide: Adafruit HUZZAH32 - ESP32 Feather Overview

As instructed, I got the needed addition to the Arduino IDE from GitHub here: espressif arduino-esp32. Under "Installation Instructions" I found how to add the espressif library to the Arduino IDE.

The Adafruit learning guide also says we need the SiLabs CP2104 Driver, found here: CP210x USB to UART Bridge VCP Drivers. This has to be compiled and installed, but the work is all done by included makefile.

This webpage says the SiLabs driver is already installed in the Linux kernel CP210x Driver in the Linux Kernel . I have another machine running Kubuntu, and the com port showed up on it without my installing any new drivers, so I guess that may be true.

Also useful: How to check if the CP210x be enumerated successfully on Linux

At this point I was getting an error during compile that indicated I needed to download a python serial library. Searching the interwebs for the error message turned up the solution.

Now I got "access denied" errors. Again, searching for the error message got me the solution.

A restart was required at this point.

At this point the Arduino IDE compiled the test program, and attempted to download it, but failed to. The only comport offered for download was "ttyS0", but this not the right port. The final link in the chain was that the microUSB cable I had was bad.

If you run the command "ls /dev/tty*" in a terminal window, you should find something like "/dev/ttyUSB0" listed. This will then also show up in the Arduino IDE undert Tools -> ports.

DigiKey's instructions at How To Program the Adafruit Huzzah32 on the Arduino IDE parallels a lot of what I found, but was not terribly helpful in that it assumes we are using a Windows machine.