golang flag簡單用法

package main

import (
  "flag"
  "strings"
  "os"
  "fmt"
)

var ARGS string

func main() {

  var uptime *bool = new(bool)
  flag.BoolVar(uptime,"u", false, "print system uptime")
  flag.Parse()

  ARGS = strings.Join(flag.Args(), " ")
  if len(os.Args)  2 {
    flag.Usage()
    os.Exit(1)
  }

  if *uptime {
    fmt.Println("12 days")
  }