Soooo... Nobody actualy posted the code so I will.
//thefunction or whatever it is called
string com = console.readline();
if (com = "shutdown")
if (com = "about")
Console.WriteLine("This is an os. Made by someone.")
//puts "This is an os. Made by someone." on the screen.
// goto TER returns to the start of TER so the user can type commands more times.
Okay thats it, post if you want more help.