我安装了sh原生Python，并开始使用命令来安装：
$ pip install sh
Collecting sh
Could not fetch URL https://pypi.python.org/simple/sh/: There was a problem confirming the ssl
certificate: [SSL: TLSV1_ALERT_PROTOCOL_VERSION] tlsv1 alert protocol version (_ssl.c:590) - skipping
Could not find a version that satisfies the requirement sh (from versions: )
No matching distribution found for sh
当上述失败时，我下载sh-1.12.14-py2.py3-none-any.whl安装到本地：
$ pip install
/Users/zhangkuixun/Downloads/sh-1.12.14-py2.py3-none-any.whl
Requirement
'/Users/zhangkuixun/Downloads/sh-1.12.14-py2.py3-none-any.whl' looks
like a filename, but the file does not exist
Processing ./Downloads/sh-1.12.14-py2.py3-none-any.whl
Exception:
Traceback (most recent call last):
File
"/Library/Python/2.7/site-packages/pip-8.1.2-py2.7.egg/pip/basecommand.py",
line …