docs: function procEnvVar(cmdOptions, index) {
    var fileEnvVar = parser.parseEnvOpts(cmdOptions);
    // process.env holds references which can cause unwanted side effects
    // cloning prevents changes to the variable values
    var processEnvVar = _.clone(process.env);
    var envVar = _.extend(processEnvVar, fileEnvVar);
    envVar.PORT = (cmdOptions.port + index);
    return envVar;
  }