flag.go

package main

import (
    "flag"
    "fmt"
)

var name = flag.String("name", "", "the name ")

var age int
func init()  {
    flag.IntVar(&age, "age", 0, "the age")
}

func main()  {
    flag.Parse()
    if len(*name) == 0 {
        flag.Usage()
        return
    }
    fmt.Printf("name: %s age:%d", *name, age)
}