Transfer files over HTTP in the LAN

sf.go

package main

import (
	"fmt"
	"net"
	"net/http"
	"os"
)

func main() {
	args := os.Args
	root := "."
	port := "8080"
	if len(args) >= 2 {
		if args[1] == "-h" {
			fmt.Println("Serve files over HTTP.\n> sf [path] [port]")
			return
		}
		root = args[1]
	}
	if len(args) >= 3 {
		port = args[2]
	}

	fmt.Println("URLs:")
	addrs, err := net.InterfaceAddrs()
	if err != nil {
		fmt.Println(err)
		os.Exit(1)
	}
	for _, addr := range addrs {
		ip := addr.(*net.IPNet).IP
		if !ip.IsLinkLocalUnicast() {
			host := ip.String()
			if ip.To4() == nil {
				host = fmt.Sprintf("[%s]", host)
			}
			fmt.Printf("  http://%s:%s\n", host, port)
		}
	}
	serve(root, port)
}

func serve(root string, port string) {
	http.Handle("/", http.FileServer(http.Dir(root)))
	fmt.Println(http.ListenAndServe(":"+port, nil))
	os.Exit(1)
}