send command to Puck.JS from the raspberry without Espruino Hub install

Looks promising.

I'd suggest changing command to:

command = "\x03\x10Bluetooth.println(beam(" +sys.argv[2]+ "));\n"

What's happening is, as mentioned in the code I posted,

\x10 -> Echo off for line so don't try and send any text back

If you removed the \x10 from the string in what you wrote, you would see data back, but you'd also see some extra characters (like the code you write echoed back to you, plus a newline and = and then your answer)

It's much easier to just stop Espruino writing stuff automatically with \x10 and then to explicitly tell it to write stuff with Bluetooth.println