You type shell commands and press <Enter> to pass them to the shell.

If you are typing a long command that will not fit on one line, you can use the \ (backslash) continuation character at the end of the first line. When you then press <Enter>, the line is cleared so that you can continue typing. The line you typed prior to the backslash is displayed in the output area, and beneath it the shell prompt changes to > (? in tcsh) to indicate that you are continuing a command.