Golang如何快速构建一个CLI小工具详解

>> gtools            
gtools is a CLI application for golang command tools.
Usage:
  gtools [command]
Available Commands:
  autoSelector randomly select string from a list
  completion   Generate the autocompletion script for the specified shell
  help         Help about any command
Flags:
  -h, --help     help for gtools
  -t, --toggle   Help message for toggle
Use "gtools [command] --help" for more infORMation about a command.

go get -u GitHub.com/spf13/cobra@latest
go install github.com/spf13/cobra-cli@latest

cobra-cli init

├── main.go
├── cmd
│   └── root.go

// 只是做了一个执行的操作
func main() {
   cmd.Execute()
}

var rootCmd = &cobra.Command{
   Use:   "gtools",  // 这是你的命令的名字
   Short: "A brief description of your application",
   Long: `A longer description that spans multiple lines and likely contains
examples and usage of using your application. For example:
Cobra is a CLI library for Go that empowers applications.
This application is a tool to generate the needed files
to quickly create a Cobra application.`,
   // Uncomment the following line if your bare application
   // has an action associated with it:
   // Run: func(cmd *cobra.Command, args []string) { },
}
// Execute adds all child commands to the root command and sets flags appropriately.
// This is called by main.main(). It only needs to happen once to the rootCmd.
func Execute() {
   err := rootCmd.Execute()
   if err != nil {
      os.Exit(1)
   }
}
func init() {
   // Here you will define your flags and configuration settings.
   // Cobra supports persistent flags, which, if defined here,
   // will be global for your application.
   // rootCmd.PersistentFlags().StringVar(&cfgFile, "config", "", "config file (default is $HOME/.main.yaml)")
   // Cobra also supports local flags, which will only run
   // when this action is called directly.
   rootCmd.Flags().BoolP("toggle", "t", false, "Help message for toggle")
}

cobra-cli add autoSelector

// autoSelectorCmd represents the autoSelector command
var autoSelectorCmd = &cobra.Command{
   Use:     "autoSelector",  // 名字
   Aliases: []string{"as"}, // 命令行的简写
   Short:   "randomly select string from a list",  //简单的描述
   Long:    `randomly select string from a list`,  //详细描述
   Run: func(cmd *cobra.Command, args []string) {
    // 在这里加入/调用你的主要逻辑
  }
}
func init() {
  // 注册到根命令下
   rootCmd.AddCommand(autoSelectorCmd)
   // Here you will define your flags and configuration settings.
   // Cobra supports Persistent Flags which will work for this command
   // and all subcommands, e.g.:
   // autoSelectorCmd.PersistentFlags().String("foo", "", "A help for foo")
   // Cobra supports local flags which will only run when this command
   // is called directly, e.g.:
   // autoSelectorCmd.Flags().BoolP("toggle", "t", false, "Help message for toggle")
}

import (
   "math/rand"
   "time"
)
// 简单实现逻辑
func AutoSelect(inputs []string) (selected string, err error) {
   source := rand.NewSource(time.Now().UnixNano())
   r := rand.New(source)
   randomIndex := r.Intn(len(inputs))
   selected = inputs[randomIndex]
   return selected, nil
}

go build -o gtools