Building CLI Applications Overview CLI apps are filters in a pipeline . They read input, transform it, write output. The Unix philosophy applies: do one thing well, compose with others. When to Use CLI vs TUI vs GUI Choose CLI when: Single operation, pipeable, scriptable, CI/CD, simple prompts Choose TUI when: Dashboard, multi-view navigation, real-time monitoring Choose GUI when: Non-technical users, complex visualizations, drag/drop Quick Reference: Libraries by Language | Language | Argument Parsing | Progress/Spinners | Colors | Prompts | |----------|-----------------|-------------------|…