digiUSB or digiCDC help for a noob on a Digispark? --SOLVED--

[DancesWithRobots]

I've managed to get a Digispark working on my Linux box (Mint 17.3).  I'm using Arduino IDE 1.6.8 with the proper board installed.  I can upload sketches and I've even gotten neopixel strandtest to work.

What I can't figure out is how to talk to it.  I've gotten digikeyboard to type out, so I know there must be some sort of serial comm going on.

But when I try to get digiUSB/echo or digiCDC/echo working, I'm at a loss.

Can someone give me a short walk through as to what to do once the sketch is loaded?  I've tried connecting via CuteCom, but I get an error "Could not open /dev/ttyUSB0" when I try to connect.  There must be some fundamental gap in my understanding of this.

Ulitimately, I want to use Python running on a RasPi to send commands to the Digispark to control a Neopixel hanging off of it.  But for now I'll settle for a simple loopback.

[DancesWithRobots]

Thank you for your reply.  I got the /dev/tty/USB0 from the bottom of the Arduino IDE which says "Digispark (default 16.5 mhz) on  /dev/ttyUSB0" which is the only way I have of knowing what port is in use since the "port" option under tools is grayed out.  When I first got into Arduino microcontrollers, I used to be able to determine the port under tools, and it was reported as "/dev/TTYS0".  Lately on my newer boards I've been seeing "/dev/ttyACM0" like you said.  BUT--apparently, you are right, because I just tried out  "/dev/ttyACM0" on CuteCom, and it connected.  Sincere gratitude and much of it.  I think I can take it from here.

OBTW, Mint is based on Ubuntu, which is based on Debian (Which you probably knew.)  I prefer the more traditional window and menu layout of Mint, rather than the sidebar thingy on Ubuntu.

Thanks again.