To install the dependencies listed in a requirements.txt file for a Flask project, you can use the pip tool, which is the package installer for Python. Follow these steps:

1. Navigate to the Project Directory: Open a terminal or command prompt and navigate to the directory where your Flask project is located. Use the cd command to change the current directory.

   cd path/to/your/flask/project
   

2. Activate Virtual Environment (Optional but recommended): If you are using a virtual environment (which is recommended for managing dependencies in Python projects), activate it. If you don’t have a virtual environment, you can skip this step.

   # On Windows
   venv\Scripts\activate
   
   # On macOS/Linux
   source venv/bin/activate
   

3. Install Dependencies: Run the following command to install the dependencies listed in the requirements.txt file:

   pip install -r requirements.txt
   

   This command reads the dependencies from requirements.txt and installs them.

4. Verify Installation: After the installation is complete, you can verify that the packages were installed by checking the active environment:

   pip list
   

   This will display a list of installed packages along with their versions.

That’s it! You’ve successfully installed the dependencies for your Flask project based on the specifications in the requirements.txt file. It’s good practice to include the requirements.txt file in your version control system (e.g., Git) so that others can easily replicate the environment.

If you are interested in studying Flask, I highly recommend this book:

The Flask Mega-Tutorial

by Miguel Grinberg Available on Amazon!