mitchellh/cli with a little UI prompt

cli-prompt.go

package main

import (
        "log"
        "os"

        "github.com/mitchellh/cli"
)

func main() {
        ui := &cli.BasicUi{
                Reader:      os.Stdin,
                Writer:      os.Stdout,
                ErrorWriter: os.Stderr,
        }
        commands := map[string]cli.CommandFactory{
                "cool": func() (cli.Command, error) {
                        return CoolCommand{Ui: ui}, nil
                },
        }
        c := &cli.CLI{
                Args:     os.Args[1:],
                Commands: commands,
        }
        code, err := c.Run()
        if err != nil {
                log.Fatal(err)
        }
        os.Exit(code)
}

type CoolCommand struct {
        Ui cli.Ui
}

func (c CoolCommand) Help() string {
        return "help thyself"
}

func (c CoolCommand) Synopsis() string {
        return c.Help()
}

func (c CoolCommand) Run(_ []string) int {
        resp, err := c.Ui.Ask("hi how are you?")
        if err != nil {
                c.Ui.Error("uh oh: " + err.Error())
                return 1
        }
        c.Ui.Info("neat, glad to hear that you are " + resp)
        return 0
}

use

❯ go run .     
Usage: app [--version] [--help] <command> [<args>]

Available commands are:
    cool    help thyself

❯ go run . cool
hi how are you? great!  # it pauses for prompt here
neat, glad to hear that you are great!