The thing I didn't (and still don't) like about the diagram is it implies the whole "ls -l" is delivered by the terminal emulator to the shell. Which isn't how

The thing I didn't (and still don't) like about the diagram is it implies the whole "ls -l" is delivered by the terminal emulator to the shell. Which isn't how it works. The emulator is transparent to all normal keystrokes and the shell is doing all the work, character by character, even for stuff like ctrl-H which, years ago, could have been (and sometimes was) intercepted and handled by the terminal driver. I don't think it's as simple as this. When the shell spawns a program, it gets out of the way and the program spawned receives all the input directly, the terminal intermediates, but the shell doesn't. For example, if you want to turn off echo (the printing of the characters you type), you need to change the terminal settings. This is done with stty -echo (go ahead and type that, you won't be able to see what you're typing), which communicates with the terminal driver to tell it to not print characters that are input. This is how password prompts are done. Witness: $ od -c hello<backspace><backspace><backspace><backspace><backspace><control-d> 0000000 od sees no input. The input was deleted by the terminal driver. Usually, the terminal is in line-input mode, so this can happen. Now, in my case, my backspace key maps to ^?, so to actually get a control-h from my backspace key, I had to do stty erase ^H. Then, the above produces: 0000000 h e l l o 177 177 177 177 177 because the backspace/erasure didn't occur at the terminal level (in fact, nothing got erased at all, nothing interpreted the input that way, and the input was passed to od plainly). Note the output of stty -a. There are a number of line editing control characters that modify the input at the terminal level before the program/shell ever even sees it. You can see this with strace -o /tmp/s.out -f bash then running od -c in that shell, typing the above, erasing it, and seeing that neither bash wakes up to handle the input and od sees no input (od's only read shows up as returning zero bytes, indicating end-of-file).