How to Install Flask on Ubuntu 18.04

Flask is a popular Python web framework that allows you to create web applications quickly and easily. In this article, we’ll show you how to install Flask on Ubuntu 18.04.

Step 1: Update the Package Repository Before installing any new software on Ubuntu, it’s always a good idea to update the package repository to make sure you have the latest version of everything. You can do this by running the following command:

sudo apt update

Step 2: Install Python and Pip Flask is a Python framework, so you’ll need to have Python installed on your system. You can check if Python is already installed by running the following command:

python3 -V

If Python is not installed, you can install it using the following command:

sudo apt install python3

Once Python is installed, you’ll also need to install pip, which is a package manager for Python. You can install pip using the following command:

sudo apt install python3-pip

Step 3: Create a Virtual Environment It’s a good idea to create a virtual environment for your Flask application so that you can isolate it from other Python applications and avoid any conflicts between different versions of Python packages. You can create a virtual environment using the following command:

python3 -m venv myprojectenv

This will create a new virtual environment in a directory called myprojectenv.

Step 4: Activate the Virtual Environment After creating the virtual environment, you need to activate it by running the following command:

source myprojectenv/bin/activate

You should see the name of your virtual environment in the command prompt, indicating that the virtual environment is now active.

Step 5: Install Flask Now that you have Python and pip installed, and you have created and activated a virtual environment for your project, you can install Flask using pip. To install Flask, run the following command:

pip install Flask

This will download and install Flask and its dependencies.

Step 6: Test the Installation To test that Flask has been installed correctly, create a new file called app.py and paste the following code into it:

from flask import Flask

app = Flask(__name__)

@app.route("/")
def hello():
    return "Hello, World!"

if __name__ == "__main__":
    app.run()

Save the file and run it using the following command:

export FLASK_APP=app.py
flask run

This will start a local web server on port 5000. Open your web browser and go http://localhost:5000/ to see the “Hello, World!” message displayed.

Step 7: Deactivate the Virtual Environment When you’re done working on your Flask application, you can deactivate the virtual environment by running the following command:

deactivate

This will return you to your normal command prompt.

Conclusion In this article, we’ve shown you how to install Flask on Ubuntu 18.04, create a virtual environment for your Flask application, and test that Flask is working correctly. With Flask installed, you’re ready to start building your own web applications!