Echo Area Customization
These variables control details of how the echo area works.
Variable: cursor-in-echo-area
This variable controls where the cursor appears when a message is displayed in the echo area. If it is non-nil, then the cursor appears at the end of the message. Otherwise, the cursor appears at point—not in the echo area at all.
The value is normally nil; Lisp programs bind it to t for brief periods of time.
Variable: echo-area-clear-hook
This normal hook is run whenever the echo area is cleared—either by (message nil) or for any other reason.
User Option: echo-keystrokes
This variable determines how much time should elapse before command characters echo. Its value must be a number, and specifies the number of seconds to wait before echoing. If the user types a prefix key (such as C-x) and then delays this many seconds before continuing, the prefix key is echoed in the echo area. (Once echoing begins in a key sequence, all subsequent characters in the same key sequence are echoed immediately.)
If the value is zero, then command input is not echoed.
Variable: message-truncate-lines
Normally, displaying a long message resizes the echo area to display the entire message, wrapping long line as needed. But if the variable message-truncate-lines is non-nil, long lines of echo-area message are instead truncated to fit the mini-window width.
The variable max-mini-window-height, which specifies the maximum height for resizing minibuffer windows, also applies to the echo area (which is really a special use of the minibuffer window; see Minibuffer Windows).