Can't read data from Serial Output?

I have an electron I’m playing with, and I’m trying to read data from the serial out but can’t. I found this tutorial (Serial Tutorial) and copied this code directly and compiled and flashed the build, but don’t see anything either over the Particle IDE on the desktop, or using the CLI on my mac. I’ve tried restarting the device but doesn’t work.

If I try a “particle serial list” that works, as does putting it in listening mode and trying 'serial identify". In system profiler on my Mac I can see “Electron” as one of the USB 3.0 devices.


I just used this code from the tutorial on an Electron:

int counter = 0;

void setup() {

void loop() {
	Serial.printlnf("testing %d", ++counter);

and it works fine. I used PuTTY and then CLI’s “particle serial monitor” command and see the “testing xx” output with both.

Maybe you should add some code to turn the D7 LED on and off, once per second, to verify that your code is actually running.