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![cobra logo ](assets/CobraMain.png )
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Cobra is a library for creating powerful modern CLI applications.
Cobra is used in many Go projects such as [Kubernetes ](https://kubernetes.io/ ),
[Hugo ](https://gohugo.io ), and [GitHub CLI ](https://github.com/cli/cli ) to
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name a few. [This list ](site/content/projects_using_cobra.md ) contains a more extensive list of projects using Cobra.
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[![ ](https://img.shields.io/github/actions/workflow/status/spf13/cobra/test.yml?branch=main&longCache=true&label=Test&logo=github%20actions&logoColor=fff )](https://github.com/spf13/cobra/actions?query=workflow%3ATest)
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[![Go Reference ](https://pkg.go.dev/badge/github.com/spf13/cobra.svg )](https://pkg.go.dev/github.com/spf13/cobra)
[![Go Report Card ](https://goreportcard.com/badge/github.com/spf13/cobra )](https://goreportcard.com/report/github.com/spf13/cobra)
[![Slack ](https://img.shields.io/badge/Slack-cobra-brightgreen )](https://gophers.slack.com/archives/CD3LP1199)
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# Overview
Cobra is a library providing a simple interface to create powerful modern CLI
interfaces similar to git & go tools.
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
* Intelligent suggestions (`app srver`... did you mean `app server` ?)
* Automatic help generation for commands and flags
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* Grouping help for subcommands
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* Automatic help flag recognition of `-h` , `--help` , etc.
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* Automatically generated shell autocomplete for your application (bash, zsh, fish, powershell)
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* 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.
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* Optional seamless integration with [viper ](https://github.com/spf13/viper ) for 12-factor apps
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# Concepts
Cobra is built on a structure of commands, arguments & flags.
**Commands** represent actions, **Args** are things and **Flags** are modifiers for those actions.
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The best applications read like sentences when used, and as a result, users
intuitively know how to interact with them.
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The pattern to follow is
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`APPNAME VERB NOUN --ADJECTIVE`
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or
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`APPNAME COMMAND ARG --FLAG` .
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A few good real world examples may better illustrate this point.
In the following example, 'server' is a command, and 'port' is a flag:
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hugo server --port=1313
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In this command we are telling Git to clone the url bare.
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git clone URL --bare
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## Commands
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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.
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In the example above, 'server' is the command.
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[More about cobra.Command ](https://pkg.go.dev/github.com/spf13/cobra#Command )
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## Flags
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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.
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In the example above, 'port' is the flag.
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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.
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# Installing
Using Cobra is easy. First, use `go get` to install the latest version
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of the library.
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```
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go get -u github.com/spf13/cobra@latest
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```
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Next, include Cobra in your application:
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```go
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import "github.com/spf13/cobra"
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```
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# Usage
`cobra-cli` is a command line program to generate cobra applications and command files.
It will bootstrap your application scaffolding to rapidly
develop a Cobra-based application. It is the easiest way to incorporate Cobra into your application.
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It can be installed by running:
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```
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go install github.com/spf13/cobra-cli@latest
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```
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For complete details on using the Cobra-CLI generator, please read [The Cobra Generator README ](https://github.com/spf13/cobra-cli/blob/main/README.md )
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For complete details on using the Cobra library, please read the [The Cobra User Guide ](site/content/user_guide.md ).
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# License
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Cobra is released under the Apache 2.0 license. See [LICENSE.txt ](LICENSE.txt )