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6bf7aab6 | 1 | @c This is part of the Emacs manual. |
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2 | @c Copyright (C) 1985, 86, 87, 93, 94, 95, 97, 2000 |
3 | @c Free Software Foundation, Inc. | |
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4 | @c See file emacs.texi for copying conditions. |
5 | @node Minibuffer, M-x, Basic, Top | |
6 | @chapter The Minibuffer | |
7 | @cindex minibuffer | |
8 | ||
9 | The @dfn{minibuffer} is the facility used by Emacs commands to read | |
10 | arguments more complicated than a single number. Minibuffer arguments | |
11 | can be file names, buffer names, Lisp function names, Emacs command | |
12 | names, Lisp expressions, and many other things, depending on the command | |
13 | reading the argument. You can use the usual Emacs editing commands in | |
14 | the minibuffer to edit the argument text. | |
15 | ||
16 | @cindex prompt | |
17 | When the minibuffer is in use, it appears in the echo area, and the | |
18 | terminal's cursor moves there. The beginning of the minibuffer line | |
19 | displays a @dfn{prompt} which says what kind of input you should supply and | |
20 | how it will be used. Often this prompt is derived from the name of the | |
21 | command that the argument is for. The prompt normally ends with a colon. | |
22 | ||
23 | @cindex default argument | |
24 | Sometimes a @dfn{default argument} appears in parentheses after the | |
25 | colon; it too is part of the prompt. The default will be used as the | |
26 | argument value if you enter an empty argument (for example, just type | |
27 | @key{RET}). For example, commands that read buffer names always show a | |
28 | default, which is the name of the buffer that will be used if you type | |
29 | just @key{RET}. | |
30 | ||
31 | The simplest way to enter a minibuffer argument is to type the text | |
32 | you want, terminated by @key{RET} which exits the minibuffer. You can | |
33 | cancel the command that wants the argument, and get out of the | |
34 | minibuffer, by typing @kbd{C-g}. | |
35 | ||
36 | Since the minibuffer uses the screen space of the echo area, it can | |
37 | conflict with other ways Emacs customarily uses the echo area. Here is how | |
38 | Emacs handles such conflicts: | |
39 | ||
40 | @itemize @bullet | |
41 | @item | |
42 | If a command gets an error while you are in the minibuffer, this does | |
43 | not cancel the minibuffer. However, the echo area is needed for the | |
44 | error message and therefore the minibuffer itself is hidden for a | |
45 | while. It comes back after a few seconds, or as soon as you type | |
46 | anything. | |
47 | ||
48 | @item | |
49 | If in the minibuffer you use a command whose purpose is to print a | |
50 | message in the echo area, such as @kbd{C-x =}, the message is printed | |
51 | normally, and the minibuffer is hidden for a while. It comes back | |
52 | after a few seconds, or as soon as you type anything. | |
53 | ||
54 | @item | |
55 | Echoing of keystrokes does not take place while the minibuffer is in | |
56 | use. | |
57 | @end itemize | |
58 | ||
59 | @menu | |
60 | * File: Minibuffer File. Entering file names with the minibuffer. | |
61 | * Edit: Minibuffer Edit. How to edit in the minibuffer. | |
62 | * Completion:: An abbreviation facility for minibuffer input. | |
63 | * Minibuffer History:: Reusing recent minibuffer arguments. | |
64 | * Repetition:: Re-executing commands that used the minibuffer. | |
65 | @end menu | |
66 | ||
67 | @node Minibuffer File | |
68 | @section Minibuffers for File Names | |
69 | ||
70 | Sometimes the minibuffer starts out with text in it. For example, when | |
71 | you are supposed to give a file name, the minibuffer starts out containing | |
72 | the @dfn{default directory}, which ends with a slash. This is to inform | |
73 | you which directory the file will be found in if you do not specify a | |
74 | directory. | |
75 | ||
76 | @c Separate paragraph to clean up ugly pagebreak--rms | |
77 | @need 1500 | |
78 | For example, the minibuffer might start out with these contents: | |
79 | ||
80 | @example | |
81 | Find File: /u2/emacs/src/ | |
82 | @end example | |
83 | ||
84 | @noindent | |
85 | where @samp{Find File:@: } is the prompt. Typing @kbd{buffer.c} | |
86 | specifies the file @file{/u2/emacs/src/buffer.c}. To find files in | |
87 | nearby directories, use @kbd{..}; thus, if you type | |
88 | @kbd{../lisp/simple.el}, you will get the file named | |
89 | @file{/u2/emacs/lisp/simple.el}. Alternatively, you can kill with | |
90 | @kbd{M-@key{DEL}} the directory names you don't want (@pxref{Words}). | |
91 | ||
92 | If you don't want any of the default, you can kill it with @kbd{C-a | |
93 | C-k}. But you don't need to kill the default; you can simply ignore it. | |
94 | Insert an absolute file name, one starting with a slash or a tilde, | |
95 | after the default directory. For example, to specify the file | |
96 | @file{/etc/termcap}, just insert that name, giving these minibuffer | |
97 | contents: | |
98 | ||
99 | @example | |
100 | Find File: /u2/emacs/src//etc/termcap | |
101 | @end example | |
102 | ||
103 | @noindent | |
104 | @cindex // in file name | |
105 | @cindex double slash in file name | |
106 | @cindex slashes repeated in file name | |
107 | GNU Emacs gives a special meaning to a double slash (which is not | |
108 | normally a useful thing to write): it means, ``ignore everything before | |
109 | the second slash in the pair.'' Thus, @samp{/u2/emacs/src/} is ignored | |
110 | in the example above, and you get the file @file{/etc/termcap}. | |
111 | ||
112 | If you set @code{insert-default-directory} to @code{nil}, the default | |
113 | directory is not inserted in the minibuffer. This way, the minibuffer | |
114 | starts out empty. But the name you type, if relative, is still | |
115 | interpreted with respect to the same default directory. | |
116 | ||
117 | @node Minibuffer Edit | |
118 | @section Editing in the Minibuffer | |
119 | ||
120 | The minibuffer is an Emacs buffer (albeit a peculiar one), and the usual | |
121 | Emacs commands are available for editing the text of an argument you are | |
122 | entering. | |
123 | ||
124 | Since @key{RET} in the minibuffer is defined to exit the minibuffer, | |
125 | you can't use it to insert a newline in the minibuffer. To do that, | |
126 | type @kbd{C-o} or @kbd{C-q C-j}. (Recall that a newline is really the | |
127 | character control-J.) | |
128 | ||
129 | The minibuffer has its own window which always has space on the screen | |
130 | but acts as if it were not there when the minibuffer is not in use. When | |
131 | the minibuffer is in use, its window is just like the others; you can | |
132 | switch to another window with @kbd{C-x o}, edit text in other windows and | |
133 | perhaps even visit more files, before returning to the minibuffer to submit | |
134 | the argument. You can kill text in another window, return to the | |
135 | minibuffer window, and then yank the text to use it in the argument. | |
136 | @xref{Windows}. | |
137 | ||
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138 | @cindex height of minibuffer |
139 | @cindex size of minibuffer | |
140 | @cindex growing minibuffer | |
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141 | @cindex resizing minibuffer |
142 | @vindex max-mini-window-height | |
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143 | There are some restrictions on the use of the minibuffer window, |
144 | however. You cannot switch buffers in it---the minibuffer and its | |
145 | window are permanently attached. Also, you cannot split or kill the | |
146 | minibuffer window. But you can make it taller in the normal fashion | |
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147 | with @kbd{C-x ^}. The minibuffer window expands vertically as necessary |
148 | to hold the text that you put in the minibuffer. Customize the variable | |
149 | @code{max-mini-window-height} to control the maximum height for resizing | |
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150 | the minibuffer window: if a floating-point number, it specifies a |
151 | fraction of the frame's height; if an integer, it specifies the maximum | |
152 | number of lines; if nil, the minibuffer window is not resized. The | |
153 | default value is 0.25. | |
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154 | |
155 | @vindex minibuffer-scroll-overlap | |
156 | Scrolling works specially in the minibuffer window. When the | |
157 | minibuffer is just one line high, and it contains a long line of text | |
158 | that won't fit on the screen, scrolling automatically maintains an | |
159 | overlap of a certain number of characters from one continuation line to | |
160 | the next. The variable @code{minibuffer-scroll-overlap} specifies how | |
161 | many characters of overlap; the default is 20. | |
162 | ||
163 | If while in the minibuffer you issue a command that displays help text | |
164 | of any sort in another window, you can use the @kbd{C-M-v} command while | |
165 | in the minibuffer to scroll the help text. This lasts until you exit | |
166 | the minibuffer. This feature is especially useful if a completing | |
167 | minibuffer gives you a list of possible completions. @xref{Other Window}. | |
168 | ||
169 | @vindex enable-recursive-minibuffers | |
170 | Emacs normally disallows most commands that use the minibuffer while | |
171 | the minibuffer is active. This rule is to prevent recursive minibuffers | |
172 | from confusing novice users. If you want to be able to use such | |
173 | commands in the minibuffer, set the variable | |
174 | @code{enable-recursive-minibuffers} to a non-@code{nil} value. | |
175 | ||
176 | @node Completion | |
177 | @section Completion | |
178 | @cindex completion | |
179 | ||
180 | For certain kinds of arguments, you can use @dfn{completion} to enter | |
181 | the argument value. Completion means that you type part of the | |
182 | argument, then Emacs visibly fills in the rest, or as much as | |
183 | can be determined from the part you have typed. | |
184 | ||
185 | When completion is available, certain keys---@key{TAB}, @key{RET}, and | |
186 | @key{SPC}---are rebound to complete the text present in the minibuffer | |
187 | into a longer string that it stands for, by matching it against a set of | |
188 | @dfn{completion alternatives} provided by the command reading the | |
189 | argument. @kbd{?} is defined to display a list of possible completions | |
190 | of what you have inserted. | |
191 | ||
192 | For example, when @kbd{M-x} uses the minibuffer to read the name of a | |
193 | command, it provides a list of all available Emacs command names to | |
194 | complete against. The completion keys match the text in the minibuffer | |
195 | against all the command names, find any additional name characters | |
196 | implied by the ones already present in the minibuffer, and add those | |
197 | characters to the ones you have given. This is what makes it possible | |
198 | to type @kbd{M-x ins @key{SPC} b @key{RET}} instead of @kbd{M-x | |
199 | insert-buffer @key{RET}} (for example). | |
200 | ||
201 | Case is normally significant in completion, because it is significant | |
202 | in most of the names that you can complete (buffer names, file names and | |
203 | command names). Thus, @samp{fo} does not complete to @samp{Foo}. | |
204 | Completion does ignore case distinctions for certain arguments in which | |
205 | case does not matter. | |
206 | ||
207 | @menu | |
208 | * Example: Completion Example. | |
209 | * Commands: Completion Commands. | |
210 | * Strict Completion:: | |
211 | * Options: Completion Options. | |
212 | @end menu | |
213 | ||
214 | @node Completion Example | |
215 | @subsection Completion Example | |
216 | ||
217 | @kindex TAB @r{(completion)} | |
218 | @findex minibuffer-complete | |
219 | A concrete example may help here. If you type @kbd{M-x au @key{TAB}}, | |
220 | the @key{TAB} looks for alternatives (in this case, command names) that | |
221 | start with @samp{au}. There are several, including | |
222 | @code{auto-fill-mode} and @code{auto-save-mode}---but they are all the | |
223 | same as far as @code{auto-}, so the @samp{au} in the minibuffer changes | |
224 | to @samp{auto-}.@refill | |
225 | ||
226 | If you type @key{TAB} again immediately, there are multiple | |
227 | possibilities for the very next character---it could be any of | |
228 | @samp{cfilrs}---so no more characters are added; instead, @key{TAB} | |
229 | displays a list of all possible completions in another window. | |
230 | ||
231 | If you go on to type @kbd{f @key{TAB}}, this @key{TAB} sees | |
232 | @samp{auto-f}. The only command name starting this way is | |
233 | @code{auto-fill-mode}, so completion fills in the rest of that. You now | |
234 | have @samp{auto-fill-mode} in the minibuffer after typing just @kbd{au | |
235 | @key{TAB} f @key{TAB}}. Note that @key{TAB} has this effect because in | |
236 | the minibuffer it is bound to the command @code{minibuffer-complete} | |
237 | when completion is available. | |
238 | ||
239 | @node Completion Commands | |
240 | @subsection Completion Commands | |
241 | ||
242 | Here is a list of the completion commands defined in the minibuffer | |
243 | when completion is available. | |
244 | ||
245 | @table @kbd | |
246 | @item @key{TAB} | |
247 | Complete the text in the minibuffer as much as possible | |
248 | (@code{minibuffer-complete}). | |
249 | @item @key{SPC} | |
250 | Complete the minibuffer text, but don't go beyond one word | |
251 | (@code{minibuffer-complete-word}). | |
252 | @item @key{RET} | |
253 | Submit the text in the minibuffer as the argument, possibly completing | |
254 | first as described below (@code{minibuffer-complete-and-exit}). | |
255 | @item ? | |
256 | Print a list of all possible completions of the text in the minibuffer | |
257 | (@code{minibuffer-list-completions}). | |
258 | @end table | |
259 | ||
260 | @kindex SPC | |
261 | @findex minibuffer-complete-word | |
262 | @key{SPC} completes much like @key{TAB}, but never goes beyond the | |
263 | next hyphen or space. If you have @samp{auto-f} in the minibuffer and | |
264 | type @key{SPC}, it finds that the completion is @samp{auto-fill-mode}, | |
265 | but it stops completing after @samp{fill-}. This gives | |
266 | @samp{auto-fill-}. Another @key{SPC} at this point completes all the | |
267 | way to @samp{auto-fill-mode}. @key{SPC} in the minibuffer when | |
268 | completion is available runs the command | |
269 | @code{minibuffer-complete-word}. | |
270 | ||
271 | Here are some commands you can use to choose a completion from a | |
272 | window that displays a list of completions: | |
273 | ||
274 | @table @kbd | |
275 | @findex mouse-choose-completion | |
276 | @item Mouse-2 | |
277 | Clicking mouse button 2 on a completion in the list of possible | |
278 | completions chooses that completion (@code{mouse-choose-completion}). | |
279 | You normally use this command while point is in the minibuffer; but you | |
280 | must click in the list of completions, not in the minibuffer itself. | |
281 | ||
282 | @findex switch-to-completions | |
283 | @item @key{PRIOR} | |
284 | @itemx M-v | |
285 | Typing @key{PRIOR} or @key{PAGE-UP}, or @kbd{M-v}, while in the | |
286 | minibuffer, selects the window showing the completion list buffer | |
287 | (@code{switch-to-completions}). This paves the way for using the | |
288 | commands below. (Selecting that window in the usual ways has the same | |
289 | effect, but this way is more convenient.) | |
290 | ||
291 | @findex choose-completion | |
292 | @item @key{RET} | |
293 | Typing @key{RET} @emph{in the completion list buffer} chooses the | |
294 | completion that point is in or next to (@code{choose-completion}). To | |
295 | use this command, you must first switch windows to the window that shows | |
296 | the list of completions. | |
297 | ||
298 | @findex next-completion | |
299 | @item @key{RIGHT} | |
300 | Typing the right-arrow key @key{RIGHT} @emph{in the completion list | |
301 | buffer} moves point to the following completion (@code{next-completion}). | |
302 | ||
303 | @findex previous-completion | |
304 | @item @key{LEFT} | |
305 | Typing the left-arrow key @key{LEFT} @emph{in the completion list | |
306 | buffer} moves point toward the beginning of the buffer, to the previous | |
307 | completion (@code{previous-completion}). | |
308 | @end table | |
309 | ||
310 | @node Strict Completion | |
311 | @subsection Strict Completion | |
312 | ||
313 | There are three different ways that @key{RET} can work in completing | |
314 | minibuffers, depending on how the argument will be used. | |
315 | ||
316 | @itemize @bullet | |
317 | @item | |
318 | @dfn{Strict} completion is used when it is meaningless to give any | |
319 | argument except one of the known alternatives. For example, when | |
320 | @kbd{C-x k} reads the name of a buffer to kill, it is meaningless to | |
321 | give anything but the name of an existing buffer. In strict | |
322 | completion, @key{RET} refuses to exit if the text in the minibuffer | |
323 | does not complete to an exact match. | |
324 | ||
325 | @item | |
326 | @dfn{Cautious} completion is similar to strict completion, except that | |
327 | @key{RET} exits only if the text was an exact match already, not | |
328 | needing completion. If the text is not an exact match, @key{RET} does | |
329 | not exit, but it does complete the text. If it completes to an exact | |
330 | match, a second @key{RET} will exit. | |
331 | ||
332 | Cautious completion is used for reading file names for files that must | |
333 | already exist. | |
334 | ||
335 | @item | |
336 | @dfn{Permissive} completion is used when any string whatever is | |
337 | meaningful, and the list of completion alternatives is just a guide. | |
338 | For example, when @kbd{C-x C-f} reads the name of a file to visit, any | |
339 | file name is allowed, in case you want to create a file. In | |
340 | permissive completion, @key{RET} takes the text in the minibuffer | |
341 | exactly as given, without completing it. | |
342 | @end itemize | |
343 | ||
344 | The completion commands display a list of all possible completions in | |
345 | a window whenever there is more than one possibility for the very next | |
346 | character. Also, typing @kbd{?} explicitly requests such a list. If | |
347 | the list of completions is long, you can scroll it with @kbd{C-M-v} | |
348 | (@pxref{Other Window}). | |
349 | ||
350 | @node Completion Options | |
351 | @subsection Completion Options | |
352 | ||
353 | @vindex completion-ignored-extensions | |
354 | When completion is done on file names, certain file names are usually | |
355 | ignored. The variable @code{completion-ignored-extensions} contains a | |
356 | list of strings; a file whose name ends in any of those strings is | |
357 | ignored as a possible completion. The standard value of this variable | |
358 | has several elements including @code{".o"}, @code{".elc"}, @code{".dvi"} | |
359 | and @code{"~"}. The effect is that, for example, @samp{foo} can | |
360 | complete to @samp{foo.c} even though @samp{foo.o} exists as well. | |
361 | However, if @emph{all} the possible completions end in ``ignored'' | |
362 | strings, then they are not ignored. Ignored extensions do not apply to | |
363 | lists of completions---those always mention all possible completions. | |
364 | ||
365 | @vindex completion-auto-help | |
366 | Normally, a completion command that finds the next character is undetermined | |
367 | automatically displays a list of all possible completions. If the variable | |
368 | @code{completion-auto-help} is set to @code{nil}, this does not happen, | |
369 | and you must type @kbd{?} to display the possible completions. | |
370 | ||
371 | @pindex complete | |
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372 | @cindex Partial Completion mode |
373 | @vindex partial-completion-mode | |
374 | @findex partial-completion-mode | |
375 | @vindex PC-include-file-path | |
376 | @vindex PC-disable-includes | |
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377 | The @code{complete} library implements a more powerful kind of |
378 | completion that can complete multiple words at a time. For example, it | |
379 | can complete the command name abbreviation @code{p-b} into | |
380 | @code{print-buffer}, because no other command starts with two words | |
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381 | whose initials are @samp{p} and @samp{b}. To enable this, use the |
382 | command @kbd{M-x partial-completion-mode} or customize the option | |
383 | @code{partial-completion-mode}. Unless the option | |
384 | @code{PC-disable-includes} is @code{t}, Partial Completion mode also | |
385 | extends @kbd{M-x find-file} so that the @samp{<@dots{}>} sequence is | |
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386 | interpreted as a file on the path @code{PC-include-file-path} and |
387 | partial completion of file names is possible. Partial completion of | |
388 | directories in file names requires @samp{*}s to indicate the | |
389 | completions: @file{/u*/b*/f*} might expand to @file{/usr/bin/foo}. When | |
390 | Partial Completion mode is active, the Meta versions of the @kbd{TAB}, | |
391 | @kbd{SPC}, @kbd{RET} and @kbd{?} keys act as those keys do by default | |
392 | for completion. | |
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393 | |
394 | @cindex Icomplete mode | |
8efd3a2b | 395 | @findex icomplete-mode |
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396 | Icomplete mode presents a constantly-updated display that tells you |
397 | what completions are available for the text you've entered so far. The | |
398 | command to enable or disable this minor mode is @kbd{M-x | |
399 | icomplete-mode}. | |
400 | ||
401 | @node Minibuffer History | |
402 | @section Minibuffer History | |
403 | @cindex minibuffer history | |
404 | @cindex history of minibuffer input | |
405 | ||
406 | Every argument that you enter with the minibuffer is saved on a | |
407 | @dfn{minibuffer history list} so that you can use it again later in | |
408 | another argument. Special commands load the text of an earlier argument | |
409 | in the minibuffer. They discard the old minibuffer contents, so you can | |
410 | think of them as moving through the history of previous arguments. | |
411 | ||
412 | @table @kbd | |
413 | @item @key{UP} | |
414 | @itemx M-p | |
415 | Move to the next earlier argument string saved in the minibuffer history | |
416 | (@code{previous-history-element}). | |
417 | @item @key{DOWN} | |
418 | @itemx M-n | |
419 | Move to the next later argument string saved in the minibuffer history | |
420 | (@code{next-history-element}). | |
421 | @item M-r @var{regexp} @key{RET} | |
422 | Move to an earlier saved argument in the minibuffer history that has a | |
423 | match for @var{regexp} (@code{previous-matching-history-element}). | |
424 | @item M-s @var{regexp} @key{RET} | |
425 | Move to a later saved argument in the minibuffer history that has a | |
426 | match for @var{regexp} (@code{next-matching-history-element}). | |
427 | @end table | |
428 | ||
429 | @kindex M-p @r{(minibuffer history)} | |
430 | @kindex M-n @r{(minibuffer history)} | |
431 | @findex next-history-element | |
432 | @findex previous-history-element | |
433 | The simplest way to reuse the saved arguments in the history list is | |
434 | to move through the history list one element at a time. While in the | |
435 | minibuffer, use @kbd{M-p} or up-arrow (@code{previous-history-element}) | |
436 | to ``move to'' the next earlier minibuffer input, and use @kbd{M-n} or | |
437 | down-arrow (@code{next-history-element}) to ``move to'' the next later | |
438 | input. | |
439 | ||
440 | The previous input that you fetch from the history entirely replaces | |
441 | the contents of the minibuffer. To use it as the argument, exit the | |
442 | minibuffer as usual with @key{RET}. You can also edit the text before | |
443 | you reuse it; this does not change the history element that you | |
444 | ``moved'' to, but your new argument does go at the end of the history | |
445 | list in its own right. | |
446 | ||
447 | For many minibuffer arguments there is a ``default'' value. In some | |
448 | cases, the minibuffer history commands know the default value. Then you | |
449 | can insert the default value into the minibuffer as text by using | |
450 | @kbd{M-n} to move ``into the future'' in the history. Eventually we | |
451 | hope to make this feature available whenever the minibuffer has a | |
452 | default value. | |
453 | ||
454 | @findex previous-matching-history-element | |
455 | @findex next-matching-history-element | |
456 | @kindex M-r @r{(minibuffer history)} | |
457 | @kindex M-s @r{(minibuffer history)} | |
458 | There are also commands to search forward or backward through the | |
459 | history; they search for history elements that match a regular | |
460 | expression that you specify with the minibuffer. @kbd{M-r} | |
461 | (@code{previous-matching-history-element}) searches older elements in | |
462 | the history, while @kbd{M-s} (@code{next-matching-history-element}) | |
463 | searches newer elements. By special dispensation, these commands can | |
464 | use the minibuffer to read their arguments even though you are already | |
465 | in the minibuffer when you issue them. As with incremental searching, | |
466 | an uppercase letter in the regular expression makes the search | |
467 | case-sensitive (@pxref{Search Case}). | |
468 | ||
469 | @ignore | |
470 | We may change the precise way these commands read their arguments. | |
471 | Perhaps they will search for a match for the string given so far in the | |
472 | minibuffer; perhaps they will search for a literal match rather than a | |
473 | regular expression match; perhaps they will only accept matches at the | |
474 | beginning of a history element; perhaps they will read the string to | |
475 | search for incrementally like @kbd{C-s}. To find out what interface is | |
476 | actually available, type @kbd{C-h f previous-matching-history-element}. | |
477 | @end ignore | |
478 | ||
479 | All uses of the minibuffer record your input on a history list, but | |
480 | there are separate history lists for different kinds of arguments. For | |
481 | example, there is a list for file names, used by all the commands that | |
482 | read file names. (As a special feature, this history list records | |
483 | the absolute file name, no more and no less, even if that is not how | |
484 | you entered the file name.) | |
485 | ||
486 | There are several other very specific history lists, including one for | |
487 | command names read by @kbd{M-x}, one for buffer names, one for arguments | |
488 | of commands like @code{query-replace}, and one for compilation commands | |
489 | read by @code{compile}. Finally, there is one ``miscellaneous'' history | |
490 | list that most minibuffer arguments use. | |
491 | ||
492 | @vindex history-length | |
493 | The variable @code{history-length} specifies the maximum length of a | |
494 | minibuffer history list; once a list gets that long, the oldest element | |
495 | is deleted each time an element is added. If the value of | |
496 | @code{history-length} is @code{t}, though, there is no maximum length | |
497 | and elements are never deleted. | |
498 | ||
499 | @node Repetition | |
500 | @section Repeating Minibuffer Commands | |
501 | @cindex command history | |
502 | @cindex history of commands | |
503 | ||
504 | Every command that uses the minibuffer at least once is recorded on a | |
505 | special history list, together with the values of its arguments, so that | |
506 | you can repeat the entire command. In particular, every use of | |
507 | @kbd{M-x} is recorded there, since @kbd{M-x} uses the minibuffer to read | |
508 | the command name. | |
509 | ||
510 | @findex list-command-history | |
511 | @c widecommands | |
512 | @table @kbd | |
513 | @item C-x @key{ESC} @key{ESC} | |
514 | Re-execute a recent minibuffer command (@code{repeat-complex-command}). | |
515 | @item M-x list-command-history | |
516 | Display the entire command history, showing all the commands | |
517 | @kbd{C-x @key{ESC} @key{ESC}} can repeat, most recent first. | |
518 | @end table | |
519 | ||
520 | @kindex C-x ESC ESC | |
521 | @findex repeat-complex-command | |
522 | @kbd{C-x @key{ESC} @key{ESC}} is used to re-execute a recent | |
523 | minibuffer-using command. With no argument, it repeats the last such | |
524 | command. A numeric argument specifies which command to repeat; one | |
525 | means the last one, and larger numbers specify earlier ones. | |
526 | ||
527 | @kbd{C-x @key{ESC} @key{ESC}} works by turning the previous command | |
528 | into a Lisp expression and then entering a minibuffer initialized with | |
529 | the text for that expression. If you type just @key{RET}, the command | |
530 | is repeated as before. You can also change the command by editing the | |
531 | Lisp expression. Whatever expression you finally submit is what will be | |
532 | executed. The repeated command is added to the front of the command | |
533 | history unless it is identical to the most recently executed command | |
534 | already there. | |
535 | ||
536 | Even if you don't understand Lisp syntax, it will probably be obvious | |
537 | which command is displayed for repetition. If you do not change the | |
538 | text, it will repeat exactly as before. | |
539 | ||
540 | Once inside the minibuffer for @kbd{C-x @key{ESC} @key{ESC}}, you can | |
541 | use the minibuffer history commands (@kbd{M-p}, @kbd{M-n}, @kbd{M-r}, | |
542 | @kbd{M-s}; @pxref{Minibuffer History}) to move through the history list | |
543 | of saved entire commands. After finding the desired previous command, | |
544 | you can edit its expression as usual and then resubmit it by typing | |
545 | @key{RET} as usual. | |
546 | ||
547 | @vindex command-history | |
548 | The list of previous minibuffer-using commands is stored as a Lisp | |
549 | list in the variable @code{command-history}. Each element is a Lisp | |
550 | expression which describes one command and its arguments. Lisp programs | |
551 | can re-execute a command by calling @code{eval} with the | |
552 | @code{command-history} element. |