vendor/github.com/mitchellh/cli/README.md

   1 # Go CLI Library [![GoDoc](https://godoc.org/github.com/mitchellh/cli?status.png)](https://godoc.org/github.com/mitchellh/cli)
   2
   3 cli is a library for implementing powerful command-line interfaces in Go.
   4 cli is the library that powers the CLI for
   5 [Packer](https://github.com/mitchellh/packer),
   6 [Serf](https://github.com/hashicorp/serf),
   7 [Consul](https://github.com/hashicorp/consul),
   8 [Vault](https://github.com/hashicorp/vault),
   9 [Terraform](https://github.com/hashicorp/terraform), and
  10 [Nomad](https://github.com/hashicorp/nomad).
  11
  12 ## Features
  13
  14 * Easy sub-command based CLIs: `cli foo`, `cli bar`, etc.
  15
  16 * Support for nested subcommands such as `cli foo bar`.
  17
  18 * Optional support for default subcommands so `cli` does something
  19   other than error.
  20
  21 * Support for shell autocompletion of subcommands, flags, and arguments
  22   with callbacks in Go. You don't need to write any shell code.
  23
  24 * Automatic help generation for listing subcommands
  25
  26 * Automatic help flag recognition of `-h`, `--help`, etc.
  27
  28 * Automatic version flag recognition of `-v`, `--version`.
  29
  30 * Helpers for interacting with the terminal, such as outputting information,
  31   asking for input, etc. These are optional, you can always interact with the
  32   terminal however you choose.
  33
  34 * Use of Go interfaces/types makes augmenting various parts of the library a
  35   piece of cake.
  36
  37 ## Example
  38
  39 Below is a simple example of creating and running a CLI
  40
  41 ```go
  42 package main
  43
  44 import (
  45         "log"
  46         "os"
  47
  48         "github.com/mitchellh/cli"
  49 )
  50
  51 func main() {
  52         c := cli.NewCLI("app", "1.0.0")
  53         c.Args = os.Args[1:]
  54         c.Commands = map[string]cli.CommandFactory{
  55                 "foo": fooCommandFactory,
  56                 "bar": barCommandFactory,
  57         }
  58
  59         exitStatus, err := c.Run()
  60         if err != nil {
  61                 log.Println(err)
  62         }
  63
  64         os.Exit(exitStatus)
  65 }
  66 ```
  67