Python 2.6 and 2.7 in Mac OS X In my /usr/bin, the following is the result of ls -al python*:

-rwxr-xr-x  1 root  wheel  66480 Dec  3 01:36 python
-rwxr-xr-x  5 root  wheel    925 Aug 22  2015 python-config
lrwxr-xr-x  1 root  wheel     75 Oct 17 21:26 python2.6 -&gt; ../../System/Library/Frameworks/Python.framework/Versions/2.6/bin/python2.6
lrwxr-xr-x  1 root  wheel     82 Oct 17 21:26 python2.6-config -&gt; ../../System/Library/Frameworks/Python.framework/Versions/2.6/bin/python2.6-config
lrwxr-xr-x  1 root  wheel     75 Oct 17 21:26 python2.7 -&gt; ../../System/Library/Frameworks/Python.framework/Versions/2.7/bin/python2.7
lrwxr-xr-x  1 root  wheel     82 Oct 17 21:26 python2.7-config -&gt; ../../System/Library/Frameworks/Python.framework/Versions/2.7/bin/python2.7-config
-rwxr-xr-x  1 root  wheel  66480 Dec  3 01:35 pythonw
lrwxr-xr-x  1 root  wheel     76 Oct 17 21:26 pythonw2.6 -&gt; ../../System/Library/Frameworks/Python.framework/Versions/2.6/bin/pythonw2.6
lrwxr-xr-x  1 root  wheel     76 Oct 17 21:26 pythonw2.7 -&gt; ../../System/Library/Frameworks/Python.framework/Versions/2.7/bin/pythonw2.7


There are three: python, python2.6, python2.7. What are they and why do I have three? Can I delete some of them? 

Well, I have another python from the anaconda installation, which I mainly use.
python is a hardlink to pythonw. The rest are symbolic links to their respective versions within the python framework. No, you should not remove them. It is not uncommon for a operating system to have multiple version of python.