Answers for "switching python versions"

how to change python version on linux

#Check available versions
ls /usr/bin/python*
#Change the used version 3.5 or 3.7 etc
alias python='/usr/bin/python3.x'
#do this other thing
. ~/.bashrc
#Check version 
python --version

switching versions of python

# Check your python version 
python --version
Python 3.9.0 
# Check the python installation list 
pyenv install --list 
[Whole list available for you, pick yours]
pyenv install 3.9.1
pyenv global 3.9.1 
python --version 
Python 3.9.1