如何在homebrew中将python3符号链接更改为“python”

Question

I want to install python using homebrew and I noticed there are 2 different formulas for it, one for python 2.x and another for 3.x. The first symlinks "python" and the other uses "python3". so I ran brew install python3 .

I really only care about using python 3 so I would like the default command to be "python" instead of having to type "python3" every time. Is there a way to do this? I tried brew switch python 3.3 but I get a "python is not found in the Cellar" error.

Answer 1

You definitely do not want to do this! You may only care about Python 3, but many people write code that expects python to symlink to Python 2. Changing this can seriously mess your system up.

Answer 2

If you are absolutely sure that you will never want to install / use Python 2, I think you can just create additional symlinks in /usr/local/bin. Check for everything that links to something in

../Cellar/python3/3.3.0/

and create a link without the 3 at the end, like

python -> ../Cellar/python3/3.3.0/bin/python3

Think twice though, why give up the advantages of having two Pythons side-by-side? Maybe just use the homebrew Python as intended, and create your Python 3 environments with virtualenv.

Answer 3

If you're doing this for personal use, don't change the symlink for python . Many of your system programs depend on python pointing to Python 2.6, and you'll break them if you change the symlink.

Instead, pick a shorter name like py and write an alias for it in ~/.bashrc , like alias py=python3 .

For example, with testing:

$ echo "alias py=python3" >> ~/.bashrc
$ bash
$ py
>>> 3+3
6

This will give you the convenience without effecting the system or other users.

Answer 4

Yes, far better to use [virtual environments] ( https://docs.python.org/3/library/venv.html ) for python 3 than mess with the system default

pyvenv /path/to/new/virtual/environment

which will setup python 3 as the default python and also isolate pip installs to that environment which is what you want to do on any project.

Answer 5

As mentioned this is not the best idea. However, the simplest thing to do when necessary is run python3 in terminal. If you need to run something for python3 then run python3