Cobra 快速入门 - 专为命令行程序而生

# server是 commands，port 是 flag
hugo server --port=1313
# clone 是 commands，URL 是 arguments，brae 是 flag
git clone URL --bare

xcbeyond@xcbeyonddeMacBook-Pro ~ % docker info --help 
Usage:  docker info [OPTIONS]
Display system-wide information
Options:
  -f, --format string   Format the output using the given Go template

go get -u github.com/spf13/cobra/cobra

xcbeyond@xcbeyonddeMacBook-Pro github % .\bin\cobra init cobra-demo --pkg-name github.com/xcbeyond/cobra-demo
Your Cobra application is ready at
/Users/xcbeyond/github/cobra-demo

.
├── cmd
│   ├── root.go
│   └── show.go
├── go.mod
├── go.sum
└── main.go

xcbeyond@xcbeyonddeMacBook-Pro cobra-demo % go run main.go
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.

xcbeyond@xcbeyonddeMacBook-Pro cobra-demo % ../bin/cobra add show
show created at /Users/xcbeyond/github/cobra-demo

// showCmd represents the show command
var showCmd = &cobra.Command{
    Use:   "show",
    Short: "A brief description of your command",
    Long: `A longer description that spans multiple lines and likely contains examples
and usage of using your command. 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.`,
    Run: func(cmd *cobra.Command, args []string) {
        fmt.Println("show called")
    },
}
func init() {
    rootCmd.AddCommand(showCmd)
    // Here you will define your flags and configuration settings.
    // Cobra supports Persistent Flags which will work for this command
    // and all subcommands, e.g.:
    // showCmd.PersistentFlags().String("foo", "", "A help for foo")
    // Cobra supports local flags which will only run when this command
    // is called directly, e.g.:
    // showCmd.Flags().BoolP("toggle", "t", false, "Help message for toggle")
}

var showCmd = &cobra.Command{
    Use:   "show",
    Short: "A brief description of your command",
    Long: `A longer description that spans multiple lines and likely contains examples
and usage of using your command. 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.`,
    Run: func(cmd *cobra.Command, args []string) {
        // show current time
        fmt.Println(time.Now())
    },
}

var showCmd = &cobra.Command{
    Use:   "show",
    Short: "Displays the current time",
    Long: `You can use the time show command to view the current time. For example:
$ ./cobra-demo show
2021-03-19 14:34:20.9320241 +0800 CST m=+0.378845301`,
    Run: func(cmd *cobra.Command, args []string) {
        // show current time
        fmt.Println(time.Now())
    },
}

xcbeyond@xcbeyonddeMacBook-Pro cobra-demo % go run main.go show
2021-07-31 14:49:27.3582836 +0800 CST m=+0.176660901

xcbeyond@xcbeyonddeMacBook-Pro cobra-demo % go run main.go show --help
You can use the time show command to view the current time. For example:
$ ./cobra-demo show
2021-07-31 14:34:20.9320241 +0800 CST m=+0.378845301
Usage:
cobra-demo show [flags]
Flags:
-h, --help   help for show
Global Flags:
        --config string   config file (default is $HOME/.cobra-demo.yaml)