golang flag简单用法

package mainimport (  "flag"  "strings"  "os"  "fmt")var ARGS stringfunc 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")  }