Building python from source on Ubuntu 20.04 LTS Focal Fossa
Learn how to build your favourite language from its source code on Linux based operating system.
PS: Apart from users facing dependency issues ,this blog is for anyone who would love to try installing python from source code on any Linux based operating systems
If you have upgraded your operating system and wandering why some libraries which were easily install-able on Ubuntu 18.04 are not getting installed on 20.04. I faced the same issue when one of my development environment required a library which I tried to install using the built-in python. Unfortunately, I faced a dependency issue.
The reason behind this was Ubuntu 20.04 comes with built in python version 3.8.2 whereas Ubuntu 18.04 comes with Python 3.6.x
There may be different libraries which you are trying to install which depends on Python 3.6. Don’t worry its as easy as 1..2..3
Let’s start with a specific python version, I will be using Python 3.6.9 in this blog because on the previous system I was working on it.
First Things First
Install essential dependencies required for building library
sudo apt-get update
sudo apt-get install -y build-essential checkinstall and
sudo apt-get install libreadline-gplv2-dev libncursesw5-dev libssl-dev libsqlite3-dev tk-dev libgdbm-dev libc6-dev libbz2-devLets Build
Start with changing the directory and downloading source code from python.
I will be installing it from /usr/src but you can use any location of your choice
cd /usr/src
sudo wget https://www.python.org/ftp/python/3.6.9/Python-3.6.9.tgzExtracting downloaded package
sudo tar xzf Python-3.6.9.tgzCompiling Source
cd Python-3.6.9
sudo ./configure --enable-optimizationsHere we have added a new flag --enable-optimizations
This sets the default make targets up to enable Profile Guided Optimization (PGO) and may be used to auto-enable Link Time Optimization (LTO) on some platforms.
Refer here for more details on --enable-optimizations
Step we all are waiting for
Building python
sudo make altinstallWhy altinstall when we can use install
Reason: On Unix and Mac systems if you intend to install multiple versions of Python you must take care that your primary python executable is not
overwritten by the installation of a different version.altinstallbuilds specific version of python without overwriting your default version so that you can use multiple version of python.Note: This step may take time depending on device configuration
The python version will be built with suffix python3.6
Verify Installation
python3.6 --versionNotice I have used python3.6 instead. If you try to run python3 --version it will show built-in python version which is 3.8 as of Ubuntu 20.04
Build everything with a single command
I have created a shell script for the same, you can download the script file from here.
Upgrading pip (optional)
Install dependency for pip
sudo apt-get install -y python3-distutils python3-testresourcesDownloading get-pip.py and running
cd ~/
wget https://bootstrap.pypa.io/get-pip.py
sudo python3.6 get-pip.pyJust like python3.6 use prefix pip3.6 for installation like this
Bonus
If you are annoyed by using python3.6 or pip3.6 each time, just use any one of the configurations mentioned below.
Using alias
alias py36=python3.6
alias pip36=pip3.6
Limitations of alias command:
Either you run this command each time before running python or pip or add these lines at the bottom of your~/.bashrcbut it will only run on user level.
The best solution for fixing this is usingupdate-alternatives
Using update-alternatives
Check your python path for adding it to update-alternatives config
which python3.6My path was /usr/local/bin/python3.6
Adding path to update-alternatives config
sudo update-alternatives --install /usr/bin/python python /usr/local/bin/python3.6 0If you enjoy my blog and would like to support my work, consider buying me a coffee. Your contribution will help me keep the blog running and creating valuable content. Thank you!
