Go CLI Library

cli is a library for implementing powerful command-line interfaces in Go.
cli is the library that powers the CLI for
Packer,
Serf,
Consul,
Vault,
Terraform, and
Nomad.

Features

• Easy sub-command based CLIs: cli foo, cli bar, etc.

• Support for nested subcommands such as cli foo bar.

• Optional support for default subcommands so cli does something
  other than error.

• Support for shell autocompletion of subcommands, flags, and arguments
  with callbacks in Go. You don't need to write any shell code.

• Automatic help generation for listing subcommands

• Automatic help flag recognition of -h, --help, etc.

• Automatic version flag recognition of -v, --version.

• Helpers for interacting with the terminal, such as outputting information,
  asking for input, etc. These are optional, you can always interact with the
  terminal however you choose.

• Use of Go interfaces/types makes augmenting various parts of the library a
  piece of cake.

Example

Below is a simple example of creating and running a CLI

package main

import (
	"log"
	"os"

	"github.com/mitchellh/cli"
)

func main() {
	c := cli.NewCLI("app", "1.0.0")
	c.Args = os.Args[1:]
	c.Commands = map[string]cli.CommandFactory{
		"foo": fooCommandFactory,
		"bar": barCommandFactory,
	}

	exitStatus, err := c.Run()
	if err != nil {
		log.Println(err)
	}

	os.Exit(exitStatus)
}