simple explanation how to save code that espruino run on start?

@tve, how about putting your default stuff in a module (in project folder modules) from where you can grab it? For example:

// env_tve_xyz.js - module
exports.nw = "myWifiNetworkName"; // wifi network / access point id / ssid
exports.pw = " myWifiNetworkPassword"; // wifi network access / password

// application code
var env = require("env_tve_xyz");
...
...env.nw... // using wifi network / access point id / ssid
...env.pw... // using wifi network access / password
...