go语言命令行程序（CLI）开发工具小记

package main

import (
   "flag"
   "fmt"
)

// 适用于最简单的 只有一组命令行参数的情况

// 带有等号的格式
// eg： go run main.go -name=ikun -id=29238 -male

// 不带有等号的格式
// eg： go run main.go -name ikun -id 29238 -male
func main() {
   var name string
   var studentId int
   var isMale bool

   // 定义 flag.xxxVar(&变量, 参数名, 默认值, 帮助信息)
   flag.StringVar(&name, "name", "caixukun.666", "姓名")
   flag.IntVar(&studentId, "id", 128, "学号")
   flag.BoolVar(&isMale, "male", false, "是男性")

   // 注意一定要有解析 否则变量都是默认值
   flag.Parse()

   // 查看解析结果
   fmt.Printf("Name=%s, StudentId=%d, IsMale=%tn", name, studentId, isMale)
}

package main服务器托管网

import (
   "flag"
   "fmt"
)

// 适用于有子命令的情况

// 不带有等号的格式
// eg:  student子命令: go run main.go student -name ikun -id 29238 -male
// eg:  student子命令: go run main.go teacher -name mayun -salary 20000

// 带有等号的格式
// eg:  student子命令: go run main.go student -name=ikun -id=29238 -male
// eg:  student子命令: go run main.go teacher -name=mayun -salary=20000
func main() {
   //首先要用全局默认FlagSet解析一遍 否则flag.Args是无效的。
   flag.Parse()
   flagArgs := flag.Args()
   switch flagArgs[0] {
   case "student":// student子命令解析
      var name string
      var studentId int
      var isMale bool
      stuendtFlags := flag.NewFlagSet("student", flag.ExitOnError)
      stuendtFlags.StringVar(&name, "name", "caixu服务器托管网kun.666", "姓名")
      stuendtFlags.IntVar(&studentId, "id", 128, "学号")
      stuendtFlags.BoolVar(&isMale, "male", false, "是否男性")

      // 索引从1开始 索引0是子命令 "student" 字符串
      err := stuendtFlags.Parse(flagArgs[1:])
      if err != nil {
         fmt.Printf("Student Invalid cmd optionn")
         return
      }
      fmt.Printf("Student: Name=%s, StudentId=%d, IsMale=%tn", name, studentId, isMale)
   case "teacher":
      var name string
      var salary int64
      teacherFlags := flag.NewFlagSet("teacher", flag.ExitOnError)
      teacherFlags.StringVar(&name, "name", "caixukun.666", "姓名")
      teacherFlags.Int64Var(&salary, "salary", 128, "薪资")
      err := teacherFlags.Parse(flagArgs[1:])
      if err != nil {
         fmt.Printf("Teacher Invalid cmd optionn")
         return
      }
      fmt.Printf("Teacher: Name=%s, Salary=%dn", name, salary)
   default:
      fmt.Printf("Invalid cmd optionn")
   }
}

package main

import (
	"fmt"
	"os"

	"github.com/jawher/mow.cli"
)

func main() {
	// create an app
	app := cli.App("cp", "Copy files around")

	// Here's what differentiates mow.cli from other CLI libraries:
	// This line is not just for help message generation.
	// It also validates the call to reject calls with less than 2 arguments
	// and split the arguments between SRC or DST
	app.Spec = "[-r] SRC... DST"

	var (
		// declare the -r flag as a boolean flag
		recursive = app.BoolOpt("r recursive", false, "Copy files recursively")
		// declare the SRC argument as a multi-string argument
		src = app.StringsArg("SRC", nil, "Source files to copy")
		// declare the DST argument as a single string (string slice) arguments
		dst = app.StringArg("DST", "", "Destination where to copy files to")
	)

	// Specify the action to execute when the app is invoked correctly
	app.Action = func() {
		fmt.Printf("Copying %v to %s [recursively: %v]n", *src, *dst, *recursive)
	}

	// Invoke the app passing in os.Args
	app.Run(os.Args)
}