golang flag用法

基本函数说明

//生成命令行参数对应的变量，变量为指针类型
var name = flag.String("name", "Tom", "Input your name")
var age = flag.Int("age", 18, "Input your age")
var vip = flag.Bool("flag", true, "Is VIP")

其中"name","age","flag"对应在命令行中通过如下格式指定参数

-name=Jack
-name Jack
--name=Jack
--name Jack

//定义值类型的命令行参数变量，xxxVar对其进行初始化。可以为Int，String，Bool
var postCode int
flag.IntVar(&postCode, "Postcode", 1234, "Input your post code")

//接受命令行参数
flag.Parse()

//返回没有被解析的命令行参数的个数
flag.NArg()

//返回没有被解析的命令行参数
flag.Args()

//命令行设置的参数个数
flag.NFlag()

示例

package main

import (
    "flag"
    "fmt"
)

var name = flag.String("name", "Tom", "Input your name")
var age = flag.Int("age", 18, "Input your age")
var f = flag.Bool("isVIP", false, "Is VIP")
var postCode int

func init() {
    flag.IntVar(&postCode, "postcode", 1234, "Input your post code")
}

func main() {
    flag.Parse()

    fmt.Println("name:", *name)
    fmt.Println("age:", *age)
    fmt.Println("VIP:", *f)
    fmt.Println("postCode:", postCode)

    fmt.Println("tail:", flag.Args())
    fmt.Println(flag.NArg())
    fmt.Println(flag.NFlag())

    args := os.Args
    fmt.Println("Args:", args)

    paramCnt := flag.NArg()
    for cnt := 0; cnt < paramCnt; cnt++ {
        fmt.Println(flag.Arg(cnt))
    }
}

执行测试

./flagtest -name=Bill -age=22 -isVIP=true --postcode=3235 otherParam1 otherParam2
name: Bill
age: 22
VIP: true
postCode: 3235
tail: [otherParam1 otherParam2]
2
4
Args: [./clitest -name=Bill -age=22 -isVIP=true --postcode=3235 otherParam1 otherParam2]
otherParam1
otherParam2

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