code: func initConfig() {
  	if cfgFile != "" { // enable ability to specify config file via flag
  		viper.SetConfigFile(cfgFile)
  	}
  
  	viper.SetConfigName(".fstack") // name of config file (without extension)
  	viper.AddConfigPath("$HOME")   // adding home directory as first search path
  	viper.AutomaticEnv()           // read in environment variables that match
  
  	// If a config file is found, read it in.
  	if err := viper.ReadInConfig(); err == nil {
  		fmt.Println("Using config file:", viper.ConfigFileUsed())
  	}
  
  	fs, err := fstack.OpenStack(stackFile)
  	if err != nil {
  		panic(err)
  	}
  	stack = fs
  }
docs: // initConfig reads in config file and ENV variables if set.