How do I generate shell autocompletion scripts with cmdr?

Cmdr provides built-in functions to generate autocompletion scripts for shells like bash, zsh, fish, and PowerShell. You can invoke these during app initialization or via commands, and the README notes it can auto-install for zsh.

Is cmdr better than Cobra for Go CLI apps?

Cmdr excels in hierarchical configuration management and offers flexible command definitions, while Cobra has a larger ecosystem and community support. Choose cmdr if you need advanced config integration; opt for Cobra for broader third-party tools and plugins.

Can cmdr automatically bind flags to environment variables?

Yes, cmdr supports automatic binding to environment variables. For example, setting HELP=1 in the environment is equivalent to passing --help on the command line, as mentioned in the README under POSIX-compliant parser features.

What are the main changes from cmdr v1 to v2?

V2 was rewritten for cleaner code, splitting features like the option store into hedzr/store and introducing new APIs. It focuses on stability but may have breaking changes, as noted in the motivation section about refactoring from v1.

How to define subcommands using struct tags in cmdr?

You can use the BuildFrom method or FromStruct to define commands and flags via struct tags. This declarative style maps Go struct fields to CLI elements, with examples provided in the README's 'From a struct value' section.

Does cmdr support Windows PowerShell autocompletion?

Yes, cmdr includes support for generating autocompletion scripts for PowerShell, along with other shells like bash and zsh, as listed in the features for shell autocompletion generation.

cmdr — POSIX CLI Argument Parser for Go

What is cmdr?

Cmdr is a Go library for building command-line interface (CLI) applications with a focus on parsing arguments and managing configurations. It provides a robust foundation for developers to create CLI tools with features like subcommands, flag parsing, and integration with external configuration sources. The library emphasizes clean, maintainable code and flexibility, allowing developers to choose the command-building approach that best fits their project while ensuring stability and performance.

Target Audience

Go developers building CLI tools who need advanced features like hierarchical configuration management, shell autocompletion, and manpage generation. It is particularly suited for those creating complex CLI applications with multiple subcommands and requiring integration with various configuration sources.

Value Proposition

Developers choose Cmdr over alternatives for its POSIX-compliant parser with support for compact flag combinations, flexible command-building styles (traditional stream calls, concise builders, struct-based definitions), and seamless integration with hedzr/store for hierarchical configuration management. Its unique selling points include smart help with typo suggestions using Jaro-Winkler distance and automatic generation of shell autocompletion scripts and manpages.

POSIX-compliant command-line UI (CLI) parser and Hierarchical-configuration operations

Use Cases

Best For

Building CLI applications with complex subcommand hierarchies and flag parsing requirements.
Developing Go-based CLI tools that need integration with multiple configuration sources like environment variables, config files, Consul, or etcd.
Creating CLI applications that require automatic shell autocompletion for zsh, bash, fish, or PowerShell.
Generating manual pages (manpages) for deployment to enhance end-user documentation.
Implementing CLI tools with flexible command definition styles, including struct-based definitions via tags for cleaner code organization.
Building CLI applications that need smart typo suggestions for commands and flags using Jaro-Winkler distance.

Not Ideal For

Developers building simple, single-command CLI tools without subcommands or advanced configuration needs
Projects prioritizing minimal dependencies and lightweight libraries, as cmdr relies on multiple hedzr modules
Teams already standardized on Cobra or similar frameworks who value extensive community plugins and tooling

Pros & Cons

Pros

POSIX-Compliant Parsing

Supports compact flag combinations like `-c1b23zv` and handles sticky values, offering flexibility for complex CLI syntax as described in the README.

Hierarchical Configuration Integration

Integrates with hedzr/store for high-performance KV storage and loading from multiple sources like environment variables, config files, Consul, and etcd, with automatic type conversion.

Flexible Command Building

Provides three styles—traditional stream calls, concise builders, and struct-based definitions via tags—allowing developers to choose the approach that best fits their codebase.

Smart Help and Suggestions

Auto-generates help screens and uses Jaro-Winkler distance to suggest corrections for typos in commands and flags, improving user experience.

Autocompletion and Manpage Generation

Generates shell autocompletion scripts for zsh, bash, fish, and PowerShell, and creates manual pages for deployment, enhancing documentation and usability.

Cons

Dependency Heavy

Relies on several hedzr libraries (store, logg, evendeep, is), which can increase project complexity, bloat, and potential versioning issues compared to minimalist alternatives.

Steep Learning Curve

With multiple command-building paradigms and integrated configuration management, newcomers may find it overwhelming to grasp all options and best practices quickly.

API and Feature Maturity

The README mentions a TODO list and historical breaking changes from v1 to v2, indicating some features may be incomplete or subject to instability in future updates.

Frequently Asked Questions

What is cmdr?

Target Audience

Value Proposition

Use Cases

Best For

Building CLI applications with complex subcommand hierarchies and flag parsing requirements.
Developing Go-based CLI tools that need integration with multiple configuration sources like environment variables, config files, Consul, or etcd.
Creating CLI applications that require automatic shell autocompletion for zsh, bash, fish, or PowerShell.
Generating manual pages (manpages) for deployment to enhance end-user documentation.
Implementing CLI tools with flexible command definition styles, including struct-based definitions via tags for cleaner code organization.
Building CLI applications that need smart typo suggestions for commands and flags using Jaro-Winkler distance.

Not Ideal For

Developers building simple, single-command CLI tools without subcommands or advanced configuration needs
Projects prioritizing minimal dependencies and lightweight libraries, as cmdr relies on multiple hedzr modules
Teams already standardized on Cobra or similar frameworks who value extensive community plugins and tooling

Pros & Cons

Pros

POSIX-Compliant Parsing

Supports compact flag combinations like `-c1b23zv` and handles sticky values, offering flexibility for complex CLI syntax as described in the README.

Hierarchical Configuration Integration

Integrates with hedzr/store for high-performance KV storage and loading from multiple sources like environment variables, config files, Consul, and etcd, with automatic type conversion.

Flexible Command Building

Provides three styles—traditional stream calls, concise builders, and struct-based definitions via tags—allowing developers to choose the approach that best fits their codebase.

Smart Help and Suggestions

Auto-generates help screens and uses Jaro-Winkler distance to suggest corrections for typos in commands and flags, improving user experience.

Autocompletion and Manpage Generation

Generates shell autocompletion scripts for zsh, bash, fish, and PowerShell, and creates manual pages for deployment, enhancing documentation and usability.

Cons

Dependency Heavy

Relies on several hedzr libraries (store, logg, evendeep, is), which can increase project complexity, bloat, and potential versioning issues compared to minimalist alternatives.

Steep Learning Curve

With multiple command-building paradigms and integrated configuration management, newcomers may find it overwhelming to grasp all options and best practices quickly.

API and Feature Maturity

The README mentions a TODO list and historical breaking changes from v1 to v2, indicating some features may be incomplete or subject to instability in future updates.

Frequently Asked Questions

cmdr

What is cmdr?

Overview

Use Cases

Best For

Not Ideal For

Pros & Cons

Pros

Cons

Frequently Asked Questions

Related Projects

Found a gem we're missing?

cmdr

What is cmdr?

Overview

Use Cases

Best For

Not Ideal For

Pros & Cons

Pros

Cons

Frequently Asked Questions

Related Projects

Found a gem we're missing?