在 Mac 上使用 `pip install tornado` 得到错误：权限被拒绝：'/Library/Python/2.7/site-packages/singledispatch.py答案

【问题标题】：Use the `pip install tornado` on Mac get error:Permission denied: '/Library/Python/2.7/site-packages/singledispatch.py在 Mac 上使用 `pip install tornado` 得到错误：权限被拒绝：'/Library/Python/2.7/site-packages/singledispatch.py
【发布时间】：2017-05-29 01:08:34
【问题描述】：

在 Mac 上使用 pip install tornado 会出错：

aircraftdeMacBook-Pro:~ ldl$ pip install tornado
Collecting tornado
  Downloading tornado-4.5.1.tar.gz (483kB)
    100% |████████████████████████████████| 491kB 565kB/s 
Collecting singledispatch (from tornado)
  Downloading singledispatch-3.4.0.3-py2.py3-none-any.whl
Collecting certifi (from tornado)
  Downloading certifi-2017.4.17-py2.py3-none-any.whl (375kB)
    100% |████████████████████████████████| 378kB 565kB/s 
Collecting backports_abc>=0.4 (from tornado)
  Downloading backports_abc-0.5-py2.py3-none-any.whl
Requirement already satisfied: six in /System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python (from singledispatch->tornado)
Installing collected packages: singledispatch, certifi, backports-abc, tornado
Exception:
Traceback (most recent call last):
  File "/Library/Python/2.7/site-packages/pip-9.0.1-py2.7.egg/pip/basecommand.py", line 215, in main
    status = self.run(options, args)
  File "/Library/Python/2.7/site-packages/pip-9.0.1-py2.7.egg/pip/commands/install.py", line 342, in run
    prefix=options.prefix_path,
  File "/Library/Python/2.7/site-packages/pip-9.0.1-py2.7.egg/pip/req/req_set.py", line 784, in install
    **kwargs
  File "/Library/Python/2.7/site-packages/pip-9.0.1-py2.7.egg/pip/req/req_install.py", line 851, in install
    self.move_wheel_files(self.source_dir, root=root, prefix=prefix)
  File "/Library/Python/2.7/site-packages/pip-9.0.1-py2.7.egg/pip/req/req_install.py", line 1064, in move_wheel_files
    isolated=self.isolated,
  File "/Library/Python/2.7/site-packages/pip-9.0.1-py2.7.egg/pip/wheel.py", line 345, in move_wheel_files
    clobber(source, lib_dir, True)
  File "/Library/Python/2.7/site-packages/pip-9.0.1-py2.7.egg/pip/wheel.py", line 323, in clobber
    shutil.copyfile(srcfile, destfile)
  File "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/shutil.py", line 83, in copyfile
    with open(dst, 'wb') as fdst:
IOError: [Errno 13] Permission denied: '/Library/Python/2.7/site-packages/singledispatch.py'

【问题讨论】：

标签： macos tornado

【解决方案1】：

经过挣扎，我用sudo pip install tornado解决了。

Collecting tornado
  Downloading tornado-4.5.1.tar.gz (483kB)
    100% |████████████████████████████████| 491kB 557kB/s 
Collecting singledispatch (from tornado)
  Downloading singledispatch-3.4.0.3-py2.py3-none-any.whl
Collecting certifi (from tornado)
  Downloading certifi-2017.4.17-py2.py3-none-any.whl (375kB)
    100% |████████████████████████████████| 378kB 641kB/s 
Collecting backports_abc>=0.4 (from tornado)
  Downloading backports_abc-0.5-py2.py3-none-any.whl
Requirement already satisfied: six in /System/Library/Frameworks/Python.framework/Versions/2.7/Extras/lib/python (from singledispatch->tornado)
Installing collected packages: singledispatch, certifi, backports-abc, tornado
  Running setup.py install for tornado ... done
Successfully installed backports-abc-0.5 certifi-2017.4.17 singledispatch-3.4.0.3 tornado-4.5.1

【讨论】：

【解决方案2】：

一般来说，当指令说：

要安装 package123 运行 pip install package123

99% 的情况下，它假设包被安装在 Python 虚拟环境中（通过 virtualenv 或 venv）。话虽如此，您应该在虚拟环境中安装 Tornado 并避免使用sudo pip install tornado。如果您确实使用 sudo，除了使用 3rd 方模块污染您的系统包之外，没有什么不好的事情发生。

【讨论】：

【解决方案3】：

试试pip install tornado。
如果终端出现任何权限错误，请尝试sudo pip install tornado。

【讨论】：