can pass host info as argument

main.go

import (
	"log"
	"net/http"
	"os"
	"path/filepath"
)
		log.Fatal(err)
	}
	log.Println("Server running at http://localhost:8000")
	log.Fatal(http.ListenAndServe(":8000", http.FileServer(http.Dir(d))))
	addr := os.Args[1]
	if addr == "" {
		addr = ":8000"
	}
	log.Println("Server running at " + addr)
	log.Fatal(http.ListenAndServe(addr, http.FileServer(http.Dir(d))))
}