> if we ever switch 'python' to 'python3'... you won't know on a given machine if it's python2 or python3 This kind of already happened. Arch already has Pytho

> if we ever switch 'python' to 'python3'... you won't know on a given machine if it's python2 or python3 This kind of already happened. Arch already has Python 3 as 'python', and if you use any of the popular environment tools (virtualenv, pyenv, conda), whichever version of Python you pick when creating an environment will be 'python' inside that env. It's not that big a problem, though. It's quite possible to write code that runs on both Python 2 and 3, and it's surprisingly rare (in my experience) to call unqualified 'python' rather than using an explicit path.