# Command-Line Tool Architecture Questions

## Language and Runtime

1. **Primary language:**
   - Go (compiled, single binary, great for CLIs)
   - Rust (compiled, safe, performant)
   - Python (interpreted, easy distribution via pip)
   - Node.js/TypeScript (npm distribution)
   - Bash/Shell script (lightweight, ubiquitous)
   - Ruby (gem distribution)
   - Java/Kotlin (JVM, jar)
   - C/C++ (compiled, fastest)
   - Other: **\_\_\_**

2. **Target platforms:**
   - Linux only
   - macOS only
   - Windows only
   - Linux + macOS
   - All three (Linux + macOS + Windows)
   - Specific Unix variants: **\_\_\_**

3. **Distribution method:**
   - Single binary (compiled)
   - Script (interpreted, needs runtime)
   - Package manager (npm, pip, gem, cargo, etc.)
   - Installer (brew, apt, yum, scoop, chocolatey)
   - Container (Docker)
   - Multiple methods

## CLI Architecture

4. **Command structure:**
   - Single command (e.g., `grep pattern file`)
   - Subcommands (e.g., `git commit`, `docker run`)
   - Hybrid (main command + subcommands)
   - Interactive shell (REPL)

5. **Argument parsing library:**
   - Go: cobra, cli, flag
   - Rust: clap, structopt
   - Python: argparse, click, typer
   - Node: commander, yargs, oclif
   - Bash: getopts, manual parsing
   - Other: **\_\_\_**

6. **Interactive mode:**
   - Non-interactive only (runs and exits)
   - Interactive prompts (inquirer, survey, etc.)
   - REPL/shell mode
   - Both modes supported

7. **Long-running process:**
   - Quick execution (completes immediately)
   - Long-running (daemon/service)
   - Can run in background
   - Watch mode (monitors and reacts)

## Input/Output

8. **Input sources:**
   - Command-line arguments
   - Flags/options
   - Environment variables
   - Config file (JSON, YAML, TOML, INI)
   - Interactive prompts
   - Stdin (pipe input)
   - Multiple sources

9. **Output format:**
   - Plain text (human-readable)
   - JSON
   - YAML
   - XML
   - CSV/TSV
   - Table format
   - User-selectable format
   - Multiple formats

10. **Output destination:**
    - Stdout (standard output)
    - Stderr (errors only)
    - File output
    - Multiple destinations
    - Quiet mode (no output)

11. **Colored output:**
    - ANSI color codes
    - Auto-detect TTY (color when terminal, plain when piped)
    - User-configurable (--color flag)
    - No colors (plain text only)

12. **Progress indication:**
    - Progress bars (for long operations)
    - Spinners (for waiting)
    - Step-by-step output
    - Verbose/debug logging
    - Silent mode option
    - None needed (fast operations)

## Configuration

13. **Configuration file:**
    - Required (must exist)
    - Optional (defaults if missing)
    - Not needed
    - Generated on first run

14. **Config file format:**
    - JSON
    - YAML
    - TOML
    - INI
    - Custom format
    - Multiple formats supported

15. **Config file location:**
    - Current directory (project-specific)
    - User home directory (~/.config, ~/.myapp)
    - System-wide (/etc/)
    - User-specified path
    - Multiple locations (cascade/merge)

16. **Environment variables:**
    - Used for configuration
    - Used for secrets/credentials
    - Used for runtime behavior
    - Not used

## Data and Storage

17. **Persistent data:**
    - Cache (temporary, can be deleted)
    - State (must persist)
    - User data (important)
    - No persistent data needed

18. **Data storage location:**
    - Standard OS locations (XDG Base Directory, AppData, etc.)
    - Current directory
    - User-specified
    - Temporary directory

19. **Database/Data format:**
    - SQLite
    - JSON files
    - Key-value store (BoltDB, etc.)
    - CSV/plain files
    - Remote database
    - None needed

## Execution Model

20. **Execution pattern:**
    - Run once and exit
    - Watch mode (monitor changes)
    - Server/daemon mode
    - Cron-style (scheduled)
    - Pipeline component (part of Unix pipeline)

21. **Concurrency:**
    - Single-threaded (sequential)
    - Multi-threaded (parallel operations)
    - Async I/O
    - Not applicable

22. **Signal handling:**
    - Graceful shutdown (SIGTERM, SIGINT)
    - Cleanup on exit
    - Not needed (quick exit)

## Networking (if applicable)

23. **Network operations:**
    - HTTP client (REST API calls)
    - WebSocket client
    - SSH client
    - Database connections
    - Other protocols: **\_\_\_**
    - No networking

24. **Authentication (if API calls):**
    - API keys (env vars, config)
    - OAuth2 flow
    - Username/password
    - Certificate-based
    - None needed

## Error Handling

25. **Error reporting:**
    - Stderr with error messages
    - Exit codes (0 = success, non-zero = error)
    - Detailed error messages
    - Stack traces (debug mode)
    - Simple messages (user-friendly)

26. **Exit codes:**
    - Standard (0 = success, 1 = error)
    - Multiple exit codes (different error types)
    - Documented exit codes

27. **Logging:**
    - Log levels (debug, info, warn, error)
    - Log file output
    - Stderr output
    - Configurable verbosity (--verbose, --quiet)
    - No logging (simple tool)

## Piping and Integration

28. **Stdin support:**
    - Reads from stdin (pipe input)
    - Optional stdin (file or stdin)
    - No stdin support

29. **Pipeline behavior:**
    - Filter (reads stdin, writes stdout)
    - Generator (no input, outputs data)
    - Consumer (reads input, no stdout)
    - Transformer (both input and output)

30. **Shell completion:**
    - Bash completion
    - Zsh completion
    - Fish completion
    - PowerShell completion
    - All shells
    - None

## Distribution and Installation

31. **Package managers:**
    - Homebrew (macOS/Linux)
    - apt (Debian/Ubuntu)
    - yum/dnf (RHEL/Fedora)
    - Chocolatey/Scoop (Windows)
    - npm/yarn (Node.js)
    - pip (Python)
    - cargo (Rust)
    - Multiple managers
    - Manual install only

32. **Installation method:**
    - Download binary (GitHub Releases)
    - Install script (curl | bash)
    - Package manager
    - Build from source
    - Container image
    - Multiple methods

33. **Binary distribution:**
    - Single binary (statically linked)
    - Multiple binaries (per platform)
    - With dependencies (bundled)

34. **Cross-compilation:**
    - Yes (build for all platforms from one machine)
    - No (need platform-specific builds)

## Updates

35. **Update mechanism:**
    - Self-update command
    - Package manager update
    - Manual download
    - No updates (stable tool)

36. **Version checking:**
    - Check for new versions on run
    - --version flag
    - No version tracking

## Documentation

37. **Help documentation:**
    - --help flag (inline help)
    - Man page
    - Online docs
    - README only
    - All of the above

38. **Examples/Tutorials:**
    - Built-in examples (--examples)
    - Online documentation
    - README with examples
    - None (self-explanatory)

## Testing

39. **Testing approach:**
    - Unit tests
    - Integration tests (full CLI execution)
    - Snapshot testing (output comparison)
    - Manual testing
    - All of the above

40. **CI/CD:**
    - GitHub Actions
    - GitLab CI
    - Travis CI
    - Cross-platform testing
    - Manual builds

## Performance

41. **Performance requirements:**
    - Must be fast (< 100ms)
    - Moderate (< 1s)
    - Can be slow (long-running tasks)

42. **Memory usage:**
    - Minimal (small files/data)
    - Streaming (large files, low memory)
    - Can use significant memory

## Special Features

43. **Watch mode:**
    - Monitor files/directories for changes
    - Auto-reload/re-run
    - Not needed

44. **Dry-run mode:**
    - Preview changes without applying
    - Not applicable

45. **Verbose/Debug mode:**
    - --verbose flag (detailed output)
    - --debug flag (even more detail)
    - Not needed

46. **Plugins/Extensions:**
    - Plugin system (user can extend)
    - Monolithic (no plugins)
    - Planned for future
