9 The Minibuffer
The minibuffer is the facility used by Emacs commands to read
arguments more complicated than a single number. Minibuffer arguments
can be file names, buffer names, Lisp function names, Emacs command
names, Lisp expressions, and many other things, depending on the command
reading the argument. You can use the usual Emacs editing commands in
the minibuffer to edit the argument text.
When the minibuffer is in use, it appears in the echo area, and the
terminal's cursor moves there. The beginning of the minibuffer line
displays a prompt in a special color, to say what kind of input
you should supply and how it will be used. Often this prompt is
derived from the name of the command that the argument is for. The
prompt normally ends with a colon.
Sometimes a default argument appears in parentheses before the
colon; it too is part of the prompt. The default will be used as the
argument value if you enter an empty argument (that is, just type
<RET>). For example, commands that read buffer names always show a
default, which is the name of the buffer that will be used if you type
just <RET>.
The simplest way to enter a minibuffer argument is to type the text
you want, terminated by <RET> which exits the minibuffer. You can
cancel the command that wants the argument, and get out of the
minibuffer, by typing C-g.
Since the minibuffer uses the screen space of the echo area, it can
conflict with other ways Emacs customarily uses the echo area. Here is how
Emacs handles such conflicts:
- If a command gets an error while you are in the minibuffer, this does
not cancel the minibuffer. However, the echo area is needed for the
error message and therefore the minibuffer itself is hidden for a
while. It comes back after a few seconds, or as soon as you type
anything.
- If in the minibuffer you use a command whose purpose is to display a
message in the echo area, such as C-x =, the message hides the
minibuffer for a while. The minibuffer contents come back after a few
seconds, or as soon as you type anything.
- Echoing of keystrokes does not take place while the minibuffer is in
use.
