cobra

Cobra is a library for creating powerful modern CLI applications in Go. It provides a simple interface for building command-line interfaces similar to git and go tools, and is used by projects such as Kubernetes, Hugo, and GitHub CLI. Key capabilities described in the README: - Easy subcommand-based CLIs such as `app server` and `app fetch` - Fully POSIX-compliant flags, including short and long versions - Nested subcommands - Global, local, and cascading flags - Intelligent suggestions for mistyped commands (e.g., suggesting `app server` for `app srver`) - Automatic help generation for commands and flags - Grouping help for subcommands - Automatic recognition of help flags such as `-h` and `--help` - Automatically generated shell autocomplete for bash, zsh, fish, and powershell - Automatically generated man pages - Command aliases - Flexibility to define custom help and usage output - Optional integration with viper for 12-factor apps Cobra is built around commands, arguments, and flags. Commands represent actions, args are things, and flags modify those actions. The recommended pattern is `APPNAME VERB NOUN --ADJECTIVE` or `APPNAME COMMAND ARG --FLAG`. Installation is done with `go get -u github.com/spf13/cobra@latest`, then importing `github.com/spf13/cobra`. A companion tool, `cobra-cli`, can be installed with `go install github.com/spf13/cobra-cli@latest` to generate application scaffolding and command files. Flag functionality is provided by the pflag library, a fork of the Go standard flag package that adds POSIX compliance while maintaining the same interface. Cobra is released under the Apache 2.0 license.