Environment setup 

Setting up virtual python environment 

I am using mainly Python for this project on my Ubuntu. Here is the way how I set up virtual environments for the different aspects of the project. Each virtual environment can have specific set of libraries, even specific versions of those libraries.

Checking the version of Python on my system with:

python3 -V

returns

Python 3.10.6

.

This will be the base Python used when creating the environement

For installing venv via pip use the following comand:

python3 -m pip install --user virtualenv

To create a virtual environment with the name venvdemo use the following command:

python3 -m venv venvdemo

A folder in the current directory will be created with the same name venvdemo If you want to place the directory for the venv not in the current directory, just provide the path. Inside the venvdemo you can find the config file pyvenv.cfg to see which Python was used for this environment. You will also find the bin directory where the activate script is located.

To activate the virtual environment you have to provide the path to activate:

source thepathto/venvdemo/bin/activate

Once the environment is active it will look something similar in the terminal :

(venvdemo) 5q@5q-PC:~/somePath/venvDemoFolder$ ls

venvdemo

Trying to remember where you placed it every time is not necessary, you can define an alias for easier activation. This is very easy. If you are in the venvdemo directory, use this command to send this line at the end of yourline that will add the alias to the end of your bashrc.

echo "alias venvdemo=\"source $(pwd)/bin/activate\"" >> ~/.bashrc

Activate the environment and install some useful libraries, as you would usually do. Here is an example:

python3 -m pip install numpy

python3 -m pip install pandas

Use the pip freeze command to make a snapshot of the libraries with their current versions. The list will be formatted in a way that later can be used for reference fo installation:

python3 -m pip freeze > requirements.txt

Open the file to see the list with libraries:

open requirements.txt

This file now can be used for installing all the same versions into another virtual environment. From inside an activated virtual environment run the next command to do that:

python -m pip install -r ../pathToTheFile/requirements.txt

To deactivate the active environment use

deactivate

and to delete a virtual environment you just have to remove its folder recursively

rm -r venvdemo

If you want to move your environment in different directory, just get the requirements and recreate it in the new place.