13" MacBook Air Terminal says " (base) UNKNOWN Usually when I open the terminal, the first part of the command line says (base) john-doe-air, but when I opened it up today, it comes up with the following.

What should I do to rectify this issue? Thank you.
NB: For privacy reasons, I have changed the name to John Doe.
The UNKNOWN part is your computer hostname, for some reasons it changed itself.
You can change the hostname from the Terminal using the following commands :
sudo scutil --set ComputerName &quot;newname&quot;
sudo scutil --set LocalHostName &quot;newname&quot;
sudo scutil --set HostName &quot;newname&quot;

Then flush your DNS cache with dscacheutil -flushcache and reboot your Mac.
You can also change it without using commands, in System Preferences &gt; Sharing &gt; Computer Name.