When you are working on the command line, how do you erase (back up over) a character? How do you delete the line you are typing? How do you terminate a program?

What will be an ideal response?

You use the erase key, usually BACKSPACE, to remove characters you have just
typed. The line kill key, usually CONTROL-U or CONTROL-X, deletes the line you are
entering. Press the interrupt key, usually CONTROL-C, to abort the program that
is running.