Command-Line Applications in Ruby: Design Patterns and Best...
summary
Practical patterns for building Ruby CLIs: keep the executable thin in the exe directory, return explicit exit codes (control‑C -> 130), separate standard out from stderr for machine output, and offer CLI, library, REPL and MCP server interfaces so agents can avoid repeated startup. Uses OptionParser for flags, formatter registry as lambdas, subprocess handling with open3.capture3 (or array args to avoid shells), and real examples—cov-loupe and wifi-wand—already implemented as CLI/library/servers and extended successfully to Ubuntu.
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chapters (7)
- 0:00Introduction
- 4:56High cohesion and low coupling
- 10:35Designing executable scripts
- 17:58Error handling and UX
- 21:48Running external commands
- 25:42Adding a ripple shell
- 28:10Documentation and interfaces
