系统中有高版本的Python， 直接pip3 install ipcalc安装，都是装到高版本的Python
系统默认的Python是2.7.6，现在想装到默认版本中，可以使用easy_install
yuyue@workplace:/usr/bin $ sudo easy_install ipcalc
Password:
Searching for ipcalc
Reading http://pypi.python.org/simple/ipcalc/
Best match: ipcalc 1.1.3
Downloading https://pypi.python.org/packages/source/i/ipcalc/ipcalc-1.1.3.tar.gz#md5=14aa5f92d316631df6c4557a0e87c61b
Processing ipcalc-1.1.3.tar.gz
Writing /tmp/easy_install-ZyioKD/ipcalc-1.1.3/setup.cfg
Running ipcalc-1.1.3/setup.py -q bdist_egg --dist-dir /tmp/easy_install-ZyioKD/ipcalc-1.1.3/egg-dist-tmp-C92sIM
zip_safe flag not set; analyzing archive contents...
Adding ipcalc 1.1.3 to easy-install.pth file
Installed /Library/Python/2.7/site-packages/ipcalc-1.1.3-py2.7.egg
Processing dependencies for ipcalc
Finished processing dependencies for ipcalc
yuyue@workplace:/usr/bin $ sudo easy_install IPy
Searching for IPy
Reading http://pypi.python.org/simple/IPy/
Best match: IPy 0.83
Downloading https://pypi.python.org/packages/source/I/IPy/IPy-0.83.tar.gz#md5=7b8c6eb4111b15aea31b67108e769712
Processing IPy-0.83.tar.gz
Writing /tmp/easy_install-XIZ3N9/IPy-0.83/setup.cfg
Running IPy-0.83/setup.py -q bdist_egg --dist-dir /tmp/easy_install-XIZ3N9/IPy-0.83/egg-dist-tmp-4Li7BL
zip_safe flag not set; analyzing archive contents...
Adding IPy 0.83 to easy-install.pth file
Installed /Library/Python/2.7/site-packages/IPy-0.83-py2.7.egg
Processing dependencies for IPy
Finished processing dependencies for IPy
yuyue@workplace:/usr/bin $ python
Python 2.7.6 (default, Sep 9 2014, 15:04:36)
[GCC 4.2.1 Compatible Apple LLVM 6.0 (clang-600.0.39)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import IPy