为什么我在尝试升级 pip 后会收到 DistributionNotFound 错误？

Question

最近在运行yolk -U，我注意到pip 需要从1.2.1 升级到1.4.1，并尽职尽责地尝试升级它

pip install --upgrade pip

虽然再次运行 yolk -U 似乎确认升级成功（pip 不再列为过期），但这会产生错误消息

Downloading/unpacking pip from https://pypi.python.org/packages/source/p/pip/pip-1.4.1.tar.gz#md5=6afbb46aeb48abac658d4df742bff714
Downloading pip-1.4.1.tar.gz (445kB): 445kB downloaded
Running setup.py egg_info for package pip

  warning: no files found matching '*.html' under directory 'docs'
  warning: no previously-included files matching '*.rst' found under directory 'docs/_build'
  no previously-included directories found matching 'docs/_build/_sources'
Installing collected packages: pip
  Found existing installation: pip 1.2.1
  Uninstalling pip:
Exception:
Traceback (most recent call last):
  File "/Library/Python/2.7/site-packages/pip-1.2.1-py2.7.egg/pip/basecommand.py", line 107, in main
  File "/Library/Python/2.7/site-packages/pip-1.2.1-py2.7.egg/pip/commands/install.py", line 261, in run
  File "/Library/Python/2.7/site-packages/pip-1.2.1-py2.7.egg/pip/req.py", line 1162, in install
  File "/Library/Python/2.7/site-packages/pip-1.2.1-py2.7.egg/pip/req.py", line 495, in uninstall
  File "/Library/Python/2.7/site-packages/pip-1.2.1-py2.7.egg/pip/req.py", line 1492, in remove
  File "/Library/Python/2.7/site-packages/pip-1.2.1-py2.7.egg/pip/util.py", line 273, in renames
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/shutil.py", line 299, in move
os.unlink(src)
OSError: [Errno 13] Permission denied: '/usr/local/bin/pip'

并且在我随后尝试使用pip 时也这样做：

Traceback (most recent call last):
  File "/usr/local/bin/pip", line 5, in <module>
    from pkg_resources import load_entry_point
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python/pkg_resources.py", line 2603, in <module>
    line, p, specs = scan_list(VERSION,LINE_END,line,p,(1,2),"version spec")
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python/pkg_resources.py", line 666, in require
    continue    # try the next older version of project
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python/pkg_resources.py", line 565, in resolve

pkg_resources.DistributionNotFound: pip==1.2.1

我之前在have been reported 看到过类似的问题，但我看到的建议都没有帮助解决这个问题。

我卡住了，无法维护我的 Python 安装。

---

我在/usr/bin/python 中使用 OS 10.8.4、Python 2.7.2。

Answer 1

根据这一行：

OSError: [Errno 13] Permission denied: '/usr/local/bin/pip'

似乎是 *nix 权限问题，尝试使用 sudo 启动升级：

sudo pip install --upgrade pip

附带说明，我建议使用这种升级方法：http://www.pip-installer.org/en/latest/installing.html#install-or-upgrade-pip

tl;dr 版本（感谢 OP 提供的信息；））：

1.从http://www.pip-installer.org/en/latest/installing.html#install-or-upgrade-pip下载并运行get-pip.py

2.如果您收到“invalid command 'egg_info'”错误，您需要使用 pip install --upgrade setuptools 或 easy_install -U 升级安装工具