Python 符号链接到 python3

Question

Answers to this question are eligible for a +50 reputation bounty . Bounty grace period has ended. JaviOverflow wants to to this question.

So I'm setting up my default variables in a new MacBook M1 and for some reason, my symlink doesn't seem to work.

Why is the following behaviour happening? The symlink from python to python3 gets lost somehow. /Users/overflow/Documents/tools is part of my PATH variable.

$ type python
python is /Users/overflow/Documents/tools/python

$ python -V
Python 2.7.16

$ ls -lah /Users/overflow/Documents/tools/python
lrwxr-xr-x  1 overflow  staff    16B  6 Oct 18:48 /Users/overflow/Documents/tools/python -> /usr/bin/python3

$ /usr/bin/python3 -V
Python 3.8.9

$ echo $PATH | sed 's/:/\n/g'
/Users/overflow/Documents/tools
/Users/overflow/Documents/Dropbox/productivity/bin
/Users/overflow/Documents/tools/confluent-6.1.0/bin
/Users/overflow/.sdkman/candidates/java/current/bin
/Users/overflow/.nvm/versions/node/v16.10.0/bin
/Users/overflow/bin
/usr/local/bin
/opt/homebrew/bin
/opt/homebrew/sbin
/usr/local/bin
/usr/bin
/bin
/usr/sbin
/sbin

Answer 1

Given the path is not being utilized, it is being overridden by a shell alias. This can be confirmed by typing set | grep python set | grep python

If you are using virtualenv :

Try: /usr/bin/python3 -m venv python3.8.9

The common MacOS python managers are:

1. pythonz

List installs using pythonz list

Change using: /usr/bin/python3 -m venv python3.8.9

2. pythonbrew

List installs pythonbrew list

Use pythonbrew switch 3.8.9 to move to the new version.

3. pyenv

Claims to use only $PATH. Included for completeness, but just in case

List installs pyenv versions

Use pyenv global 3.8.9 to move to the new version.

---

To remove any of these remove the appropriate line from your ~/.bashrc or ~/.zshrc file.

You can locate the line with grep ~/.bashrc python .

Answer 2

I can give you some general troubleshooting tips and a band-aid that can replace a symlink.

$(which python) -V

This should get you the version for python3.

Other thing worth checking:

which python2

This should point to some standard location, /usr/bin/python2 for example. If it isn't pointed there, might be worth understanding why.

In general, Macs have some quirks. The fact that a new MacBook M4 ships with Python2 as the default is a smell that you probably shouldn't try to overwrite the default value, and for whatever reason it doesn't seem to want you to.

Simple answer: set an alias.

echo 'alias python="python3"' >> ~/.zshrc && source;

This will work for you and should not interfere with any potential other systems.

Better answer:

As others have described, create a virtual environment and source venv/bin/activate .