Typically a root user sees the '#' symbol as their prompt. If they already have a prompt via the PS1 shell variable then the # symbol is usually added at the end to indicate that they are a root user in this current context.
The root user will receive: #
Example: [root@server1 ~]#_
$
The # symbol.
With the whoami command.
Command prompt is a simple term meaning the place where you can enter system commands. It has different names on different systems, Windows -cmd(Command Prompt), Linux Mac - Terminal
The shell.
There is no such command. Obviously, in order to enter a command into the prompt, Linux must already be on.
The command "finger" can tell you how many active shells are used, the users logged in, and where they logged in.
B) who
mount
The "whoami" command should show you what account you are currently using.
The basic 'who' command lets you see the time of last system boot; list of users logged-in; the current run level, etc.
There are a series of commands, depending on what and how much information you want on logged in users. The commands are: who w users finger (if installed)
Linux is an open system, Unix is not.