The very first one, period. The first shell for Unix didn't originally have a name but has since been referred to as the Thompson shell. The first shell ported to Linux was bash.
You can view the history of commands entered on a Linux system with the history command.
The history command displays all commands that have been entered into the terminal.
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
Yes. Just about everything to do with Linux on the command line is case sensitive, including commands and file names.
There is no such command. Obviously, in order to enter a command into the prompt, Linux must already be on.
In Linux, command typed at a command prompt displays a list of commands that would likely contain the command you desire. For example, to find all of the commands that have word flush in their name or descriptions type the following: man -k flush
The shell.
To use a command interpreter, you typically open a terminal or command prompt on your computer, then type commands followed by any necessary arguments or options. The interpreter reads these commands, interprets them, and executes the corresponding actions on the system. Common examples of command interpreters include the Windows Command Prompt, macOS Terminal, and Unix/Linux shells like Bash.
You just type the commands in and press Enter - very much like Microsoft's Powershell and Command Prompt, or macOS's Terminal window (which itself runs on Bash)
You can easily cycle through previously entered commands by pressing the Up key.
With the whoami command.
Innumerable. Remember that any program on Linux can be launched from the command line, so there are as many commands as there are programs.