Hi,
While I also recommend clean install on every device (for practice if no other usage), your printscreen shows that you execute the commands wrong, so let’s clear a misunderstanding:
Here at the forum we use “#” to mark a command to be executed as root, and commands that are preceded by “$” can be (and should be) executed as regular, non-privileged user. These marks are the default ending characters on your terminal’s prompt as root or as normal user (these are covered at the welcome section’s conventions).
You’ll see this marking convention throughout the world, from related books to tutorials down to simple news articles that present some terminal commands.
So in your case, if you type something like:
# fdisk -l
With the “#”, you actually mark it as a comment, and nothing will be executed (the “#” is also the mark of a comment in bash).
When you execute this:
sudo # fdisk -l
You say “sudo” without arguments, so you get an error message.
In such cases we mean “execute fdisk -l on the root terminal”.
I imagine this may be misleading at first glance, and we are so used to it we don’t really think about this could be a problem. But apparently it can. So it is not your fault, but you misused these commands, that’s why they did not work.
Sandmann