Changing Default Python version in Ubuntu

Every Ubuntu version comes with a default python version. for example: Ubuntu 20 LTS came with Python 3.8.

If you want to use different python version you can do this with update-alternatives.

Ex. If you have a later/newer version of Python like 3.8 and you want to set earlier/older version like 3.7 as default.

Step-1: Check Python version with

python --version

for purpose of this example, I assume you have python 3.8 installed in you system.

Step-2: Install the python version to set as default.

sudo apt-get install python3.7

Step-3: run the update-alternatives command to add both python version in alternatives. and set higher priority to desire version.

sudo update-alternatives --install /usr/bin/python python /usr/bin/python3.8 1
sudo update-alternatives --install /usr/bin/python python /usr/bin/python3.7 10

Now, Because we set the higher priority to python 3.7, it is the default python version now, but you can see and change the version as you need by this command.

sudo update-alternatives --config python

If Something went Wrong!

In some cases (e.g., installing or updating certain packages), you’ll get an error message if you’ve run the commands above. To update these packages, you’ll have to temporarily undo these changes. Here’s how to do that:

1. Remove all alternatives.

sudo update-alternatives --remove-all python

2. Set things as they are before.

sudo ln -s python3.8 /usr/bin/python

Setup again

Once you’re done updating these packages, execute the commands at the top to set python3.7 as the default again.

Hi, I’m Dilip Singh, a computer science student, if you want to say or share anything with me about my post and if anything not working find me on

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