![cobra logo](https://cloud.githubusercontent.com/assets/173412/10886352/ad566232-814f-11e5-9cd0-aa101788c117.png)

Cobra is both a library for creating powerful modern CLI applications as well as a program to generate applications and command files.

[![GoDoc](https://godoc.org/github.com/spf13/cobra?status.svg)](https://godoc.org/github.com/spf13/cobra)

# Table of Contents

- [Overview](#overview)

- [Concepts](#concepts)

  * [Commands](#commands)

  * [Flags](#flags)

- [Installing](#installing)

- [License](#license)

# Overview

Cobra is a library providing a simple interface to create powerful modern CLI

interfaces similar to git & go tools.

Cobra is also an application that will generate your application scaffolding to rapidly

develop a Cobra-based application.

Cobra provides:

* Easy subcommand-based CLIs: `app server`, `app fetch`, etc.

* Fully POSIX-compliant flags (including short & long versions)

* Nested subcommands

* Global, local and cascading flags

* Easy generation of applications & commands with `cobra init appname` & `cobra add cmdname`

* Intelligent suggestions (`app srver`... did you mean `app server`?)

* Automatic help generation for commands and flags

* Automatic help flag recognition of `-h`, `--help`, etc.

* Automatically generated man pages for your application

* Command aliases so you can change things without breaking them

* The flexibility to define your own help, usage, etc.

* Optional tight integration with [viper](http://github.com/spf13/viper) for 12-factor apps

# Concepts

Cobra is built on a structure of commands, arguments & flags.

**Commands** represent actions, **Args** are things and **Flags** are modifiers for those actions.

The pattern to follow is

`APPNAME VERB NOUN --ADJECTIVE.`

    or

`APPNAME COMMAND ARG --FLAG`

A few good real world examples may better illustrate this point.

In the following example, 'server' is a command, and 'port' is a flag:

    hugo server --port=1313

In this command we are telling Git to clone the url bare.

    git clone URL --bare

## Commands

Command is the central point of the application. Each interaction that

the application supports will be contained in a Command. A command can

have children commands and optionally run an action.

In the example above, 'server' is the command.

[More about cobra.Command](https://godoc.org/github.com/spf13/cobra#Command)

## Flags

A flag is a way to modify the behavior of a command. Cobra supports

fully POSIX-compliant flags as well as the Go [flag package](https://golang.org/pkg/flag/).

A Cobra command can define flags that persist through to children commands

and flags that are only available to that command.

In the example above, 'port' is the flag.

Flag functionality is provided by the [pflag

library](https://github.com/spf13/pflag), a fork of the flag standard library

which maintains the same interface while adding POSIX compliance.

# Installing

Using Cobra is easy. First, use `go get` to install the latest version

of the library. This command will install the `cobra` generator executable

along with the library and its dependencies:

Next, include Cobra in your application:

```go

import "github.com/spf13/cobra"

```

# License

Cobra is released under the Apache 2.0 license. See [LICENSE.txt](https://github.com/spf13/cobra/blob/master/LICENSE.txt)