I wanted to set set default python version to 3 instead of 2 that is default on Ubuntu 18. I tried add alias to .bashrc like:
alias python=python3
The disadvantage of editing .bashrc file is that it will not work while using the commands with sudo. I am running my Ubuntu image via Docker as root so it is disregarding this alias.
Good and easy way out from this is to run command
update-alternatives --install /usr/bin/python python /usr/bin/python3 10
This gives a priority of 10 for the path of python3.
So, if you are running this on Docker just add
RUN update-alternatives --install /usr/bin/python python /usr/bin/python3 10
To you Dockerfile.