我试图安装网络爬行框架Scrapy与终端命令：

pip install scrapy

它开始安装，然后出现以下错误：

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 316, in clobber
ensure_dir(destdir)
File "/Library/Python/2.7/site-packages/pip-9.0.1-py2.7.egg/pip/utils/__init__.py", line 83, in ensure_dir
os.makedirs(path)
File       "/System/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/os.py", line 157, in makedirs
mkdir(name, mode)
OSError: [Errno 13] Permission denied: '/Library/Python/2.7/site-packages/pyasn1'

当我尝试使用sudo安装时，我得到以下信息：

"OSError: [Errno 1] Operation not permitted: '/tmp/pip-kEkq_9-uninstall/System/Library/Frameworks/Python.‌framework/Versions/2‌.7/Extras/lib/python‌​/six-1.4.1-py2.7.egg‌​-info'" 

当我在项目文件夹中使用虚拟环境安装并尝试导入库时，它无法识别模块。

我不知道我应该做些什么来解决这个问题。有什么建议吗？