brew install不链接python3

Question

我在链接python3并将python3设置为默认python时遇到问题。

MacOS 10.13.6

这是我所做的：

$ python --version
Python 2.7.15
$ python3 --version
Python 3.7.0
$ xcode-select --version
xcode-select version 2349.
$ brew install python
...

Python has been installed as
  /usr/local/bin/python3

Unversioned symlinks `python`, `python-config`, `pip` etc. pointing to
`python3`, `python3-config`, `pip3` etc., respectively, have been installed into
  /usr/local/opt/python/libexec/bin
...

没用 python仍然是2. *

$ python --version
Python 2.7.15
$ python3 --version
Python 3.7.0
$ pip --version
pip 10.0.1 from /usr/local/lib/python2.7/site-packages/pip (python 2.7)
$ pip3 --version
pip 18.0 from /usr/local/lib/python3.7/site-packages/pip (python 3.7)

所以我做了：

$ brew link python3
Warning: Already linked: /usr/local/Cellar/python/3.7.0
To relink: brew unlink python && brew link python
$ python --version
Python 2.7.15
$ brew install python3
...

Warning: python 3.7.0 is already installed and up-to-date
To reinstall 3.7.0, run `brew reinstall python`
$ brew reinstall python

也行不通

$ brew link python3
Warning: Already linked: /usr/local/Cellar/python/3.7.0
To relink: brew unlink python && brew link python
$ python --version
Python 2.7.15
$ python3 --version
Python 3.7.0

Answer 1

我假设您的意思是您希望该命令python启动Python3解释器并pip启动pip3。

消息中有线索：

未版本控制的符号链接python，python-config，pip等指向 python3，python3-config，pip3等，已经分别安装在/ usr /本地的/ opt /蟒蛇/ libexec目录/箱

这意味着... “如果要python启动python3和pip启动命令pip3，则需要放在/usr/local/opt/python/libexec/binPATH的开头。”

因此，在您的登录脚本（$HOME/.profile或类似脚本）中，您需要输入：

export PATH=/usr/local/opt/python/libexec/bin:$PATH

然后注销并重新登录以使其生效。

顺便说一句，brew link python3仅意味着... “在/usr/local/bin/python3其中创建一个指向该符号的链接/usr/local/Cellar/python/3.7.0/python3”。

您可以通过以下方式查看该链接及其指向的位置：

ls -l /usr/local/bin/python3