A few days ago I have try to upgrade the distribution
from the source
deb http://amd64.debian.net/debian-amd64 unstable main contrib non-free
but I obtain this error message
WARNING: The following essential packages will be removed
This should NOT be done unless you know exactly what you are doing!
base-files bash
Therefore I can't install new packages which require to remove these
essential packages.
Thank you
Bye
Stefano