It'll make sure that the board is in 'plugdev', which I think your user is in by default.
I still have an error connecting sometimes, but it usually resolves itself if I try again after 30 seconds or so. Looking at the command history on Espruino it looks as if some service in Ubuntu is trying to talk to it as if it's a modem.
Espruino is a JavaScript interpreter for low-power Microcontrollers. This site is both a support community for Espruino and a place to share what you are working on.
There's a udev rule that you can copy in to /etc/udev/rules.d/ that might help: https://github.com/espruino/Espruino/blob/master/misc/45-espruino.rules
It'll make sure that the board is in 'plugdev', which I think your user is in by default.
I still have an error connecting sometimes, but it usually resolves itself if I try again after 30 seconds or so. Looking at the command history on Espruino it looks as if some service in Ubuntu is trying to talk to it as if it's a modem.