如何在Mac上安装pip？

Question

我想不出在Mac上安装pip的正确方法。我在Homebrew上安装了python@2。当我尝试安装virtualenv时，我得到这个错误：

Could not install packages due to an EnvironmentError: [Errno 13] Permission denied: '/lib/python2.7/site-packages/virtualenv.pyc'
Consider using the `--user` option or check the permissions.

这里有一些额外的诊断信息，可能会有所帮助。

Jacobs-MacBook-Pro:~ jacob$ pip -V 
pip 19.0.3 from /usr/local/lib/python2.7/site-packages/pip (python 2.7) 
Jacobs-MacBook-Pro:~ jacob$ python -m pip -V 
pip 19.1.1 from /Users/jacob/Library/Python/2.7/lib/python/site-packages/pip (python 2.7) 
Jacobs-MacBook-Pro:~ jacob$ which python 
/usr/local/bin/python 
Jacobs-MacBook-Pro:~ jacob$ ls -l /usr/local/bin/python 
lrwxr-xr-x 1 jacob admin 36 Jun 19 15:36 /usr/local/bin/python -> ../Cellar/python@2/2.7.16/bin/python 

在网络上有很多关于如何设置它的意见。其中一些是旧的，比如使用easy_install，它似乎已被弃用。我尝试了一些不同的方法，但都没有成功。

我错过了什么？

Answer 1

我想通了：

Jacobs-MacBook-Pro:bin jacob$ brew doctor
Please note that these warnings are just used to help the Homebrew maintainers
with debugging if you file an issue. If everything you use Homebrew for is
working fine: please don't worry or file an issue; just ignore this. Thanks!

Warning: A .pydistutils.cfg file was found in $HOME, which may cause Python
builds to fail. See:
  https://bugs.python.org/issue6138
  https://bugs.python.org/issue4655
Jacobs-MacBook-Pro:~ jacob$ more .pydistutils.cfg 
[install]
prefix=

我隐约记得在过去的某个时候，我把这个文件放在那里，试图使用Google App Engine SDK (DistutilsOptionError: must supply either home or prefix/exec-prefix -- not both)。我刚刚删除了它，现在pip install可以正常工作了！