python - pip upgrade 自行卸载

Question

我今天第一次使用 pip，得到了有用的消息

You are using pip version 8.1.1, however version 9.0.1 is available. You should consider upgrading via the 'pip install --upgrade pip' command.

所以，我继续前进

pip install --upgrade pip

但事情并没有按计划进行......

Collecting pip
  Downloading pip-9.0.1-py2.py3-none-any.whl (1.3MB)
    100% |████████████████████████████████| 1.3MB 510kB/s 
Installing collected packages: pip
  Found existing installation: pip 8.1.1
    Uninstalling pip-8.1.1:
Exception:
Traceback (most recent call last):
  File "//anaconda/lib/python2.7/site-packages/pip/basecommand.py", line 209, in main
    status = self.run(options, args)
  File "//anaconda/lib/python2.7/site-packages/pip/commands/install.py", line 317, in run
    prefix=options.prefix_path,
  File "//anaconda/lib/python2.7/site-packages/pip/req/req_set.py", line 726, in install
    requirement.uninstall(auto_confirm=True)
  File "//anaconda/lib/python2.7/site-packages/pip/req/req_install.py", line 746, in uninstall
    paths_to_remove.remove(auto_confirm)
  File "//anaconda/lib/python2.7/site-packages/pip/req/req_uninstall.py", line 115, in remove
    renames(path, new_path)
  File "//anaconda/lib/python2.7/site-packages/pip/utils/__init__.py", line 267, in renames
    shutil.move(old, new)
  File "//anaconda/lib/python2.7/shutil.py", line 303, in move
    os.unlink(src)
OSError: [Errno 13] Permission denied: '/anaconda/lib/python2.7/site-packages/pip-8.1.1.dist-info/DESCRIPTION.rst'
You are using pip version 8.1.1, however version 9.0.1 is available.
You should consider upgrading via the 'pip install --upgrade pip' command.

现在 pip 似乎完全从我的电脑上消失了:

$ pip
-bash: //anaconda/bin/pip: No such file or directory

pip 是否真的消失了，也就是说，它是否真的卸载然后重新安装失败，或者只是某些东西被取消了链接？以后如何避免这个问题？因为我可以想象我需要在某个时候再次升级 pip...

Answer 1

Python 附带一个用于安装 pip 的模块，无需从互联网上提取任何名为 ensurepip 的东西。使用起来非常简单，只需在终端中运行以下命令:

python -m ensurepip

从那里你可以将 pip 升级到最新的标准方式。此处提供其他文档 https://docs.python.org/3/library/ensurepip.html .