When I open a terminal, I see 'unknown0023121250f5:'. What does this mean?
When Terminal is open, do a command shift 4 and draw a box around the Terminal and then it appears on the Desktop
Use the camera thingy in the post here to upload it.
When you open System Preferences > Sharing, what appears in the Computer Name box at the top?
sudo scutil --set HostName whatever-you-want
the HostName remains the same
The hostname is being set to the result of a reverse lookup of your IP address on a local DNS server, most likely your gateway.
How do I change the name of the perrywilliams directory?
That's your user name.
I thought the Username was the name I see when the machine is at the login screen. Is this not true?
If so, how do I update the username so that what I see at the login screen is consistent with what I see at the command line?
What you see in the command prompt is the "short" user name, although this one isn't especially short. What you see in the login screen is the "full" name.
This is interesting since the admin account name is Shinda and the username is perrywilliams.
How can I update this?
I don't understand the question. You're logged in as perrywilliams.
When I turn on the machine and arrive at the login screen, perrywilliams isn't the admin username, Shinda is.
Retrieving data ...