Scrapy-Homebrew Python错误OS X

Question

我正在运行OS X版本10.9.4。

我已经运行brew install python。 我收到以下错误...有人可以向我解释发生了什么，我可以如何解决？

我正在按照本教程进行操作： http ://doc.scrapy.org/en/latest/intro/install.html（最终，我正在尝试下载Scrapy。如果有人可以提供一些非常详细的步骤，请逐步从他们的网站的教程中，我真的很感激）

=> brew install python
==> Installing python dependency: readline
==> Downloading https://downloads.sf.net/project/machomebrew/Bottles/readline-6.3.8.mavericks.bottle.tar.gz
######################################################################## 100.0%
==> Pouring readline-6.3.8.mavericks.bottle.tar.gz
==> Caveats
This formula is keg-only, which means it was not symlinked into /usr/local.

Mac OS X provides similar software, and installing this software in
parallel can cause all kinds of trouble.

OS X provides the BSD libedit library, which shadows libreadline.
er to prevent conflicts when programs look for libreadline we are
ting this GNU Readline installation to keg-only.

Generally there are no consequences of this for you. If you build your
own software and it requires this formula, you'll need to add to your
build variables:

    LDFLAGS:  -L/usr/local/opt/readline/lib
    CPPFLAGS: -I/usr/local/opt/readline/include

==> Summary
🍺  /usr/local/Cellar/readline/6.3.8: 40 files, 2.1M
==> Installing python
==> Downloading https://downloads.sf.net/project/machomebrew/Bottles/python-2.7.8_1.mavericks.bottle.2.tar.gz
######################################################################## 100.0%
==> Pouring python-2.7.8_1.mavericks.bottle.2.tar.gz
==> Caveats
Setuptools and Pip have been installed. To update them
  pip install --upgrade setuptools
  pip install --upgrade pip

You can install Python packages with
  pip install <package>

They will install into the site-package directory
  /usr/local/lib/python2.7/site-packages

See: https://github.com/Homebrew/homebrew/wiki/Homebrew-and-Python

.app bundles were installed.
Run `brew linkapps` to symlink these to /Applications.
Error: The `brew link` step did not complete successfully
The formula built, but is not symlinked into /usr/local
Could not symlink bin/2to3
Target /usr/local/bin/2to3
already exists. You may want to remove it:
  rm /usr/local/bin/2to3

To force the link and overwrite all conflicting files:
  brew link --overwrite python

To list all files that would be deleted:
  brew link --overwrite --dry-run python

Possible conflicting files are:
/usr/local/bin/2to3 -> /Library/Frameworks/Python.framework/Versions/2.7/bin/2to3
/usr/local/bin/2to3-2 -> /Library/Frameworks/Python.framework/Versions/2.7/bin/2to3-2
/usr/local/bin/2to3-2.7 -> /Library/Frameworks/Python.framework/Versions/2.7/bin/2to3-2.7
/usr/local/bin/idle -> /Library/Frameworks/Python.framework/Versions/2.7/bin/idle
/usr/local/bin/idle2 -> /Library/Frameworks/Python.framework/Versions/2.7/bin/idle2
/usr/local/bin/idle2.7 -> /Library/Frameworks/Python.framework/Versions/2.7/bin/idle2.7
/usr/local/bin/pydoc -> /Library/Frameworks/Python.framework/Versions/2.7/bin/pydoc
/usr/local/bin/pydoc2 -> /Library/Frameworks/Python.framework/Versions/2.7/bin/pydoc2
/usr/local/bin/pydoc2.7 -> /Library/Frameworks/Python.framework/Versions/2.7/bin/pydoc2.7
/usr/local/bin/python -> /Library/Frameworks/Python.framework/Versions/2.7/bin/python
/usr/local/bin/python-config -> /Library/Frameworks/Python.framework/Versions/2.7/bin/python-config
/usr/local/bin/python2 -> /Library/Frameworks/Python.framework/Versions/2.7/bin/python2
/usr/local/bin/python2-config -> /Library/Frameworks/Python.framework/Versions/2.7/bin/python2-config
/usr/local/bin/python2.7 -> /Library/Frameworks/Python.framework/Versions/2.7/bin/python2.7
/usr/local/bin/python2.7-config -> /Library/Frameworks/Python.framework/Versions/2.7/bin/python2.7-config
/usr/local/bin/pythonw -> /Library/Frameworks/Python.framework/Versions/2.7/bin/pythonw
/usr/local/bin/pythonw2 -> /Library/Frameworks/Python.framework/Versions/2.7/bin/pythonw2
/usr/local/bin/pythonw2.7 -> /Library/Frameworks/Python.framework/Versions/2.7/bin/pythonw2.7
/usr/local/bin/smtpd.py -> /Library/Frameworks/Python.framework/Versions/2.7/bin/smtpd.py
/usr/local/bin/smtpd2.7.py -> /Library/Frameworks/Python.framework/Versions/2.7/bin/smtpd2.7.py
/usr/local/bin/smtpd2.py -> /Library/Frameworks/Python.framework/Versions/2.7/bin/smtpd2.py
==> /usr/local/Cellar/python/2.7.8_1/bin/python -s setup.py --no-user-cfg install --force --verbose --install-scripts=/usr/local/Cellar/python/2.7.8_1/bin --install-lib=/usr/local/lib/python2.7/site-packa
==> /usr/local/Cellar/python/2.7.8_1/bin/python -s setup.py --no-user-cfg install --force --verbose --install-scripts=/usr/local/Cellar/python/2.7.8_1/bin --install-lib=/usr/local/lib/python2.7/site-packa
==> Summary
🍺  /usr/local/Cellar/python/2.7.8_1: 4776 files, 76M

Answer 1

您的问题是您已经在/usr/local上安装了Python 2.7（在Apple预安装到/usr的Python 2.7之上）。 最可能的猜测是您从python.org运行了官方安装程序。

由于Homebrew尝试安装到/usr/local ，并且您不能在同一位置放置两个具有相同名称的东西，因此您不能这样做。

如果您的系统上确实需要三个Python 2.7，则必须为其中一个选择不同的位置。 请注意，现有的实际上只是一堆/Library/Frameworks/Python.framework/Versions/2.7/的符号链接，而您要安装的新链接实际上只是一堆/usr/local/Cellar/python/2.7.8的符号链接。 /usr/local/Cellar/python/2.7.8 。 因此，对于任何一个来说，符号链接都不是必需的。 而且Homebrew使得不安装符号链接变得容易：只需不执行link步骤。

当然，这意味着您不能只运行pip来安装Homebrew Python的软件包，而必须使用/usr/local/Cellar/python/2.7.8/bin/pip 。 当然，您还必须运行/usr/local/Cellar/python/2.7.8/bin/python才能使用 Homebrew Python。

不用说，您可以将酒窖目录添加到PATH …但这将进一步增加您的困惑。 您可以很容易地以以下方式结束，例如， PATH上的第一个pip来自Homebrew地窖，而第一个ipython则来自python.org安装，因此您可以安装但找不到它们—或者，更糟的是， pip和您的python-config不匹配，因此每次安装都超出了C编译器的要求，这会使它感到困惑和失败。

所有这些都引发了一个问题，为什么您需要三个Python 2.7版本（至少两个在PATH ），而不是两个版本。 如果您知道自己在做什么，就可以进行这项工作……但是显然不是这种情况。 那么，为什么要让自己变得困难呢？