How to override the pip command to Python3.x instead of Python2.7?

Question

I am using OSX and I have pip installed for both Python3.5 and Python2.7. I know I can run the command pip2 to use Python2 and when I use the command pip3

Answer 1

Although PEP 394 does not specifically mention pip, it does discuss a number of other Python-related commands (including python itself). The short version is that, for reasons of backwards compatibility, the unversioned commands should refer to Python 2.x for the immediate future on most reasonable systems.

Generally, these aliases are implemented as symbolic links, and you can just flip the symlink to point at the version you want (e.g. with ln -f -s $(which pip3) $(which pip) as root). But it may not be a good idea if you have any software that expects to interact with Python 2 (which may be more than you think since a lot of software interacts with Python).

The saner option is to set up a Virtualenv with Python 3. Then, within the Virtualenv, all Python-related commands will refer to 3.x instead of 2.x. This will not break the system, unlike the previous paragraph which could well break things.