获取命令行参数 -- urfave

项目地址：
https://github.com/urfave/cli

用法：

1. 代码：

    package main
   
    import (
        "fmt"
        "github.com/urfave/cli/v2"
        "log"
        "os"
    )
   
    func main() {
        var name string
        app := &cli.App{
            Name:        "命令名称",
            Usage:       "用法",
            Version:     "v1.0",
            Description: "描述",
            Commands: []*cli.Command{
                {
                    Name:    "command-a",
                    Aliases: []string{"ca"},
                    Usage:   "command-a 用法说明",
                    Flags: []cli.Flag{
                        &cli.StringFlag{
                            Name:        "flag-a",
                            Aliases:     []string{"fa"},
                            Value:       "default-flag-a-value",
                            Usage:       "flag-a 用法",
                            Destination: &name,
                            Required:    true,
                        },
                    },
                    Action: func(ctx *cli.Context) error {
                        fmt.Println("flag: ", ctx.String("flag-a"))
                        fmt.Println("command: ", ctx.Args().First())
                        return nil
                    },
                },
                {
                    Name:    "command-b",
                    Aliases: []string{"cb"},
                    Usage:   "command-b 用法说明",
                    Flags: []cli.Flag{
                        &cli.StringFlag{
                            Name:        "flag-b",
                            Aliases:     []string{"fb"},
                            Value:       "default-flag-b-value",
                            Usage:       "flag-b 用法",
                            Destination: &name,
                            Required:    true,
                        },
                    },
                    Subcommands: []*cli.Command{
                        {
                            Name:    "command-b-a",
                            Aliases: []string{"cba"},
                            Usage:   "command-b-a 用法说明",
                            Action: func(ctx *cli.Context) error {
                                fmt.Println("flag: ", ctx.String("flag-b"))
                                fmt.Println("command: ", ctx.Args().First())
                                return nil
                            },
                        },
                        {
                            Name:    "command-b-b",
                            Aliases: []string{"cbb"},
                            Usage:   "command-b-b 用法说明",
                            Action: func(ctx *cli.Context) error {
                                fmt.Println("flag: ", ctx.String("flag-b"))
                                fmt.Println("command: ", ctx.Args().First())
                                return nil
                            },
                        },
                    },
                },
            },
        }
        err := app.Run(os.Args)
        if err != nil {
            log.Fatal(err)
        }
    }

2. 测试：

   go run test.go ca -fa faValue caValue
   go run test.go cb -fb fbValue cba cbaValue
   go run test.go cb -fb fbValue cbb cbbValue