HowTo_Console_Line_Interface.md

+# Creating Your Own Console Line Interface Functionality
+
+To add a new command to the NES CLI, follow these steps:
+
+1. **Create the script with the desired functionality**
+
+   Create a new Python script in the `nes/entrypoints/` directory, for example, `my_function.py`. 
+   This script should define the function that implements your command's logic.
+
+   ```python
+   # nes/entrypoints/my_function.py
+
+   def my_function(args):
+       """
+       Implement the functionality of your command here.
+       Args:
+           args: Parsed command-line arguments.
+       """
+       print("Executing my_function with arguments:", args)
+   ```
+
+2. **Expose the function in `__init__.py`**
+
+   Import and expose your function in the `nes/entrypoints/__init__.py` file to make it available for CLI registration.
+
+   ```python
+   # nes/entrypoints/__init__.py
+
+   from .my_function import my_function
+   
+   __all__ = [..., 'my_function']
+   ```
+
+3. **Register the command in `cli.py`**
+
+   Add a helper function to register your command's subparser in `nes/entrypoints/cli.py`. 
+   This function should add the subparser and specify the handler function.
+
+   ```python
+   # nes/entrypoints/cli.py
+
+   from nes.entrypoints import my_function
+
+   def _add_my_function(subparsers):
+       parser = subparsers.add_parser('my_function', help='Description of my_function command')
+       # Add any command-line arguments here
+       parser.add_argument('--option', type=str, help='An example option')
+       parser.set_defaults(func=my_function)
+   ```
+
+4. **Call the subparser registration in `main()`**
+
+   Inside the `main()` function of `cli.py`, call `_add_my_function()` to register your command with the CLI.
+
+   ```python
+   # nes/entrypoints/cli.py
+
+   def main():
+       import argparse
+       parser = argparse.ArgumentParser(description='NES CLI')
+       subparsers = parser.add_subparsers(title='commands', dest='command')
+
+       # Register your command here
+       _add_my_function(subparsers)
+
+       args = parser.parse_args()
+       if hasattr(args, 'func'):
+           args.func(args)
+       else:
+           parser.print_help()
+   ```
+
+**Usage Example:**
+
+After completing these steps, you can run your new command from the terminal:
+
+```bash
+python -m nes.entrypoints.cli my_function --option example_value
+```
+
+This will execute the `my_function` command with the provided option.
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