CLI Development Patterns

Modern CLI design patterns for commands, flags, output, errors, signals, config, and distribution.

Rules

Core CLI design rules extracted as discrete, actionable patterns. See rules index for the full list organized by:

• Commands & Naming - Lowercase, typeable command names
• Flags & Arguments - Standard flag conventions (-h, -v, -q, etc.)
• Configuration - Precedence order (flags > env > config > defaults)
• Output & Streams - stdout vs stderr separation
• Error Handling - Actionable error messages with clear fixes
• Signals & Lifecycle - Ctrl-C handling with timeout and force option
• Security - Never read secrets from environment variables
• Distribution - Single binary packaging when possible

References