~$ conda update conda
Solving environment: done

## Package Plan ##

  environment location: /home/david/anaconda3

  added / updated specs: 
    - conda


The following packages will be UPDATED:

    conda: 4.4.10-py36_0 --> 4.4.11-py36_0

Proceed ([y]/n)? y

Preparing transaction: done
Verifying transaction: done
Executing transaction: failed
ERROR conda.core.link:_execute(481): An error occurred while uninstalling package 'defaults::conda-4.4.10-py36_0'.
PermissionError(13, 'Permission denied')
Attempting to roll back.

Rolling back transaction: done

PermissionError(13, 'Permission denied')

Intenté actualizar conda en virtualbox ubuntu 16.04 y apareció este error de permiso. Lo intentésudo conda update conda pero vuelvesudo: conda: command not found. No estoy seguro de a dónde ir desde aquí.