change /usr/bin/python to python3 code example
Example 1: update link python is python 3
$ \python --version
Python 2.7.6
Example 2: update link python is python 3
$ unalias python
$ python --version
Python 2.7.6
$ \python --version
Python 2.7.6
$ unalias python
$ python --version
Python 2.7.6