go 的flag用法

package main

import (
	"flag"
	"fmt"
)


var (
	recusive bool 
	test string
	level int
)

func init() {
	flag.BoolVar(&recusive,"r",false,"recusive xxx")
	flag.StringVar(&test,"t","default string","string option")
	flag.IntVar(&level,"l",1,"level of xxx")  //存入变量名 名称  默认值  说明
	flag.Parse()  // 调用这个解析,参数才能生效
}

/*
输入:  ./flag_opt.exe -r true -t 333  -l 22 或者 ./flag_opt.exe -r  -t 333  -l 22
输出:
recusive:true
test:default string
level:1
 */

func main() {
	fmt.Printf("recusive:%v\n",recusive)
	fmt.Printf("test:%v\n",test)
	fmt.Printf("level:%v\n",level)
}

输出:

D:\GoPath\src\MyProject\pingguoxueyuan\gostudy\listen14\flag_opt>flag_opt.exe  -r true -t 333  -l 22
recusive:true
test:default string
level:1

D:\GoPath\src\MyProject\pingguoxueyuan\gostudy\listen14\flag_opt>flag_opt.exe  -h
Usage of flag_opt.exe:
  -l int
        level of xxx (default 1)
  -r    recusive xxx
  -t string
        string option (default "default string")