Изменение версии Python по умолчанию Ubuntu
sudo update-alternatives --set python /usr/bin/python3.6
Ugly Unicorn
sudo update-alternatives --set python /usr/bin/python3.6
#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 --versionsudo update-alternatives --install /usr/bin/python python /usr/bin/python3.4 1
sudo update-alternatives --install /usr/bin/python python /usr/bin/python3.6 2
[sudo] update-alternatives --install /usr/bin/python python /usr/bin/python3 10
sudo update-alternatives --config python