Repository files navigation

Cobra is a library for creating powerful modern CLI applications.

Cobra is used in many Go projects such asKubernetes,Hugo, andGitHub CLI toname a few.This list contains a more extensive list of projects using Cobra.

Cobra is a library providing a simple interface to create powerful modern CLIinterfaces 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 meanapp server?)
• Automatic help generation for commands and flags
• Grouping help for subcommands
• Automatic help flag recognition of-h,--help, etc.
• Automatically generated shell autocomplete for your application (bash, zsh, fish, powershell)
• 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 seamless integration withviper for 12-factor apps

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

Commands represent actions,Args are things andFlags are modifiers for those actions.

The best applications read like sentences when used, and as a result, usersintuitively know how to interact with them.

The pattern to follow isAPPNAME VERB NOUN --ADJECTIVEorAPPNAME 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

Command is the central point of the application. Each interaction thatthe application supports will be contained in a Command. A command canhave children commands and optionally run an action.

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

More about cobra.Command

A flag is a way to modify the behavior of a command. Cobra supportsfully POSIX-compliant flags as well as the Goflag package.A Cobra command can define flags that persist through to children commandsand flags that are only available to that command.

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

Flag functionality is provided by thepflaglibrary, a fork of the flag standard librarywhich maintains the same interface while adding POSIX compliance.

Using Cobra is easy. First, usego get to install the latest versionof the library.

go get -u github.com/spf13/cobra@latest

Next, include Cobra in your application:

import"github.com/spf13/cobra"

cobra-cli is a command line program to generate cobra applications and command files.It will bootstrap your application scaffolding to rapidlydevelop a Cobra-based application. It is the easiest way to incorporate Cobra into your application.

It can be installed by running:

go install github.com/spf13/cobra-cli@latest

For complete details on using the Cobra-CLI generator, please readThe Cobra Generator README

For complete details on using the Cobra library, please read theThe Cobra User Guide.

Cobra is released under the Apache 2.0 license. SeeLICENSE.txt