Getting started with CLI on RaspberryPi

It's worth trying to run espruino --list a few times, just in case. If you're using the original 1v88 firmware it doesn't send advertising packets quite quick enough, and that means that if some tools only wait a second to scan they might miss it.

You could also run espruino --list --verbose and see if any errors get reported - Noble might be trying to say that there was some error - or it's possible that NPM totally failed to install Noble at all.

There's info covering most of what you're after on the Espruino CLI tools page I think: https://github.com/espruino/EspruinoTools

You can get the battery percentage using sudo bin/espruino-cli.js -p d9:aa:73:7c:7f:cf -e "print(Puck.getBatteryPercentage())" (for example - that's my Puck's address)

At the moment there's nothing on the command-line to evaluate an expression and return just that, but you can easily strip it out:

sudo bin/espruino-cli.js -p d9:aa:73:7c:7f:cf -e "print('>>>'+Puck.getBatteryPercentage())" | sed -ne "s/^.*>>>\(.*\)$/\1/p"

However you can actually use espruino as an NPM module and can send commands and/or evaluate expressions straight in that

First step is to get it connecting to your device though.