Ubuntu 17.04 was giving me errors when I tried to
apt install or
apt upgrade any program.
It was clear from the errors (in this case, concerning python2-gtk install) were syntax errors due to Python 3 being the default in Ubuntu 17.04 beta, even though I had already installed Python 2.
This was not an issue of my
~/.bash_alias, it was an issue of
update-alternatives not having Python2 installed.
Even with Ubuntu 17.04, you must have Python 2 as the default or you may get stuck with a broken non-working
Select python2 as default Python
apt install python2 update-alternatives --install /usr/bin/python python /usr/bin/python2 20 update-alternatives --config python
Now Python 2
/usr/bin/python2 should have the highest priority in auto mode.
Therefore, older programs in Ubuntu repositories that need Python 2 due to old syntax will still work.
Yes, it is a real shame to fallback to Python 2, but we can’t have a broken computer on principle.