Is it the terminal or the shell that is responsible for actions of keystrokes? I don't know exactly if the terminal is the handler of keystrokes like CTRL + C or CTRL + D and many others or the shell. When I press a keystoke I think about it this way, as the picture describes: ![enter image description here]( When a keystroke is pressed, the keystrokes is handled by the shell, the shell interprets the keystrokes and do whatever it needs to do, perhaps sending a signal when `CTRL + C` is pressed or clearing the screen with `CTRL + L` and so on. Therefore, the shell plays the role of the middle-man for the program's inputs. Inputs go from shell to the program's stdin. The program's stdout goes to the shell, and the shell redirects the output to a terminal or files or pipes. The terminal sends the shell the bytes of the pressed keys. Am I right?

Not really. Signals etc are handled by the terminal driver, so the shell doesn't really know whether you typed a literal ctrl-C or sent it the same signal with `kill` from another window, for example.


Keystrokes -> Terminal -> Terminal driver -> Foreground process


When the shell isn't the foreground process (such as when you used it to start an interactive program, or really any foreground process at all), that program receives keyboard input and any signals from the terminal driver.

Standard input comes from the terminal by default, but you could run a shell with its input redirected from a file or a network stream, for example, and the shell doesn't really know the difference. Similarly, the shell can redirect standard input, output, and error streams for its child processes irrespectively of whether a terminal is involved at all.