[conda] conda update anaconda

[McLowery Elrod]

Last month I installed the latest ubuntu and installed Anaconda Python. I
am able to run codes that I previously developed on windows.

Recently, spyder gave me the message that an update was available. So I ran

conda update conda
conda update spyder

and everything seemed normal. Spyder continues to work for me. But then I
executed

conda update anaconda

and got the following:

PackageNotInstalledError: Package is not installed in prefix.
prefix: /home/mack/anaconda2
package name: anaconda

I get the same result for conda update anaconda2.

As additional information:

whereis conda returns

conda: /home/mack/anaconda2/bin/conda

whereis spyder returns

spyder: /home/mack/anaconda2/bin/spyder

but whereis python returns

python:
/usr/bin/python3.6m
/usr/bin/python3.6
/usr/lib/python3.7
/usr/lib/python3.6
/usr/lib/python2.7
/etc/python3.4
/etc/python
/etc/python3.5
/etc/python3.6
/etc/python2.7
/usr/local/lib/python3.6
/usr/include/python3.6m
/usr/share/python
/home/mack/anaconda2/bin/python2.7-config
/home/mack/anaconda2/bin/python
/home/mack/anaconda2/bin/python2.7

My primary question is: What do I have to do to update anaconda?
A secondary question is: Do I need to remove other versions of python?

Thanks,
Mack Elrod