Python is a versatile and powerful programming language that is widely used for a variety of applications, including web development, data analysis, artificial intelligence, and more. While there are many integrated development environments (IDEs) available for Python development, some developers prefer to use command-line tools for a streamlined and efficient workflow. In this article, we will explore 13 of the best free and open source command-line Python application development tools.

1. Black
Black is a powerful code formatter for Python that automatically formats your code according to the PEP 8 style guide. It is easy to integrate into your workflow and can help ensure that your code is consistent and readable.

2. PyLint
PyLint is a static code analysis tool that can help you identify errors, bugs, and other issues in your Python code. It provides detailed reports and can help you improve the quality of your code.

3. Flake8
Flake8 is another code analysis tool that combines several other tools, including PyFlakes, pycodestyle, and McCabe. It can help you catch errors, enforce coding standards, and improve the overall quality of your code.

4. Click
Click is a powerful command-line interface (CLI) framework for Python that makes it easy to create your own command-line applications. It is simple to use and can help you build robust and user-friendly CLIs.

5. Cookiecutter
Cookiecutter is a templating tool that allows you to create project templates for Python applications. It simplifies the process of setting up new projects and can help you get started quickly.

6. isort
isort is a utility that automatically sorts and organizes your Python imports. It can help keep your code clean and maintainable by ensuring that your imports are consistent and easy to read.

7. Python Fire
Python Fire is a library that automatically generates command-line interfaces for your Python code. It can save you time and effort by handling the boilerplate code required for creating CLIs.

8. mypy
mypy is a static type checker for Python that can help you catch type-related errors in your code. It can improve the robustness of your code and make it easier to maintain and debug.

9. Pipenv
Pipenv is a tool that simplifies package management for Python projects. It combines the functionality of pip and virtualenv and can help you manage dependencies more efficiently.

10. Poetry
Poetry is another package management tool for Python that simplifies the process of creating and managing Python projects. It can help you handle dependencies, packaging, and deployment with ease.

11. virtualenv
virtualenv is a tool that allows you to create isolated Python environments for your projects. It can help you avoid conflicts between dependencies and ensure that your projects are self-contained.

12. tox
tox is a testing tool that can help you run and manage tests for your Python projects. It can automate the testing process and ensure that your code meets the required standards.

13. flit
flit is a packaging tool for Python that can help you create and distribute Python packages. It is lightweight and easy to use, making it a great choice for managing your project’s dependencies.

In conclusion, these 13 free and open source command-line Python application development tools can help you streamline your workflow, improve the quality of your code, and simplify the development process. Whether you are a beginner or an experienced developer, these tools can help you build robust and efficient Python applications.