Support

• Always implement a help option with the two common flags: -h or --help
• Structure help sections with usage, commands, arguments, options and examples
• Provide help when users make invalid requests
• Provide documentation both at the terminal and online
• Document commands and extend documentation for your commands
• Provide auto-completion when possible

Errors

• Keep users informed
• Provide text-based error descriptions
• Present errors logically, e.g. by location or type
• Present all errors where they are the most discoverable, e.g. at the end of the command line