Go CLI Library

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

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)
}