没权限的安装模块方法
当你不是root用户时，安装模块时报错：

$ pip install Cmake
…
ERROR: Could not install packages due to an EnvironmentError: [Errno 13] Permission denied: ‘/usr/lib64/python2.7/site-packages/cmake-3.14.4.dist-info’
Consider using the --user option or check the permissions.

因为代表进行全局安装，安装后全局可用

解决办法就是：

$ pip install --user Cmake
DEPRECATION: Python 2.7 will reach the end of its life on January 1st, 2020. Please upgrade your Python as Python 2.7 won’t be maintained after that date. A future version of pip will drop support for Python 2.7.
Collecting Cmake
Using cached https://files.pythonhosted/packages/09/bb/0121c0ae40144b99420a1a0ea081d48ac4d77332600896d7e04bf23aa957/cmake-3.14.4-py2-none-manylinux2010_x86_64.whl
Installing collected packages: Cmake
Successfully installed Cmake-3.14.4

添加一个–user,代表仅该用户的安装，安装后仅该用户可用。处于安全考虑，尽量使用该命令进行安装。

记得卸载的时候也要添加 --user