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6bf7aab6 | 1 | @c This is part of the Emacs manual. |
67675c0f | 2 | @c Copyright (C) 1985, 86, 87, 93, 94, 95, 97, 2000 Free Software Foundation, Inc. |
6bf7aab6 DL |
3 | @c See file emacs.texi for copying conditions. |
4 | @node Basic, Minibuffer, Exiting, Top | |
5 | @chapter Basic Editing Commands | |
6 | ||
7 | @kindex C-h t | |
8 | @findex help-with-tutorial | |
9 | We now give the basics of how to enter text, make corrections, and | |
10 | save the text in a file. If this material is new to you, you might | |
11 | learn it more easily by running the Emacs learn-by-doing tutorial. To | |
12 | use the tutorial, run Emacs and type @kbd{Control-h t} | |
13 | (@code{help-with-tutorial}). | |
14 | ||
15 | To clear the screen and redisplay, type @kbd{C-l} (@code{recenter}). | |
16 | ||
17 | @menu | |
18 | ||
19 | * Inserting Text:: Inserting text by simply typing it. | |
20 | * Moving Point:: How to move the cursor to the place where you want to | |
21 | change something. | |
22 | * Erasing:: Deleting and killing text. | |
23 | * Undo:: Undoing recent changes in the text. | |
24 | * Files: Basic Files. Visiting, creating, and saving files. | |
25 | * Help: Basic Help. Asking what a character does. | |
26 | * Blank Lines:: Commands to make or delete blank lines. | |
27 | * Continuation Lines:: Lines too wide for the screen. | |
28 | * Position Info:: What page, line, row, or column is point on? | |
29 | * Arguments:: Numeric arguments for repeating a command. | |
30 | * Repeating:: A short-cut for repeating the previous command. | |
31 | @end menu | |
32 | ||
33 | @node Inserting Text | |
34 | @section Inserting Text | |
35 | ||
36 | @cindex insertion | |
37 | @cindex graphic characters | |
38 | To insert printing characters into the text you are editing, just type | |
39 | them. This inserts the characters you type into the buffer at the | |
40 | cursor (that is, at @dfn{point}; @pxref{Point}). The cursor moves | |
41 | forward, and any text after the cursor moves forward too. If the text | |
42 | in the buffer is @samp{FOOBAR}, with the cursor before the @samp{B}, | |
43 | then if you type @kbd{XX}, you get @samp{FOOXXBAR}, with the cursor | |
44 | still before the @samp{B}. | |
45 | ||
06a97e7d RS |
46 | To @dfn{delete} text you have just inserted, use the large key |
47 | labeled @key{DEL}, @key{BACKSPACE} or @key{DELETE} which is a short | |
48 | distance above the @key{RET} or @key{ENTER} key. This is the key you | |
9ab48fa6 | 49 | normally use, outside Emacs, for erasing the last character that you |
bf1a7e14 RS |
50 | typed. Regardless of the label on that key, Emacs thinks of it as |
51 | @key{DEL}, and that's what we call it in this manual. | |
6bf7aab6 | 52 | |
06a97e7d RS |
53 | The @key{DEL} key deletes the character @emph{before} the cursor. |
54 | As a consequence, the cursor and all the characters after it move | |
55 | backwards. If you type a printing character and then type @key{DEL}, | |
56 | they cancel out. | |
57 | ||
9ab48fa6 RS |
58 | On most computers, Emacs recognizes automatically which key ought to |
59 | be @key{DEL}, and sets it up that way. But in some cases, especially | |
60 | with text-only terminals, you will need to tell Emacs which key to use | |
61 | for that purpose. If the large key not far above the @key{RET} or | |
62 | @key{ENTER} key doesn't delete backwards, you need to do this. | |
82f6ab38 | 63 | @xref{DEL Does Not Delete}, for an explanation of how. |
9ab48fa6 | 64 | |
83b344c5 RS |
65 | Most PC keyboards have both a @key{BACKSPACE} key a short ways above |
66 | @key{RET} or @key{ENTER}, and a @key{DELETE} key elsewhere. On these | |
67 | keyboards, Emacs supports when possible the usual convention that the | |
68 | @key{BACKSPACE} key deletes backwards (it is @key{DEL}), while the | |
69 | @key{DELETE} key deletes ``forwards,'' deleting the character after | |
70 | point, the one underneath the cursor, like @kbd{C-d} (see below). | |
06a97e7d | 71 | |
6bf7aab6 DL |
72 | @kindex RET |
73 | @cindex newline | |
74 | To end a line and start typing a new one, type @key{RET}. This | |
75 | inserts a newline character in the buffer. If point is in the middle of | |
76 | a line, @key{RET} splits the line. Typing @key{DEL} when the cursor is | |
77 | at the beginning of a line deletes the preceding newline, thus joining | |
78 | the line with the preceding line. | |
79 | ||
80 | Emacs can split lines automatically when they become too long, if you | |
81 | turn on a special minor mode called @dfn{Auto Fill} mode. | |
82 | @xref{Filling}, for how to use Auto Fill mode. | |
83 | ||
84 | If you prefer to have text characters replace (overwrite) existing | |
85 | text rather than shove it to the right, you can enable Overwrite mode, | |
86 | a minor mode. @xref{Minor Modes}. | |
87 | ||
88 | @cindex quoting | |
89 | @kindex C-q | |
90 | @findex quoted-insert | |
91 | Direct insertion works for printing characters and @key{SPC}, but other | |
92 | characters act as editing commands and do not insert themselves. If you | |
93 | need to insert a control character or a character whose code is above 200 | |
94 | octal, you must @dfn{quote} it by typing the character @kbd{Control-q} | |
95 | (@code{quoted-insert}) first. (This character's name is normally written | |
96 | @kbd{C-q} for short.) There are two ways to use @kbd{C-q}:@refill | |
97 | ||
98 | @itemize @bullet | |
99 | @item | |
100 | @kbd{C-q} followed by any non-graphic character (even @kbd{C-g}) | |
101 | inserts that character. | |
102 | ||
103 | @item | |
104 | @kbd{C-q} followed by a sequence of octal digits inserts the character | |
105 | with the specified octal character code. You can use any number of | |
9acb8eec RS |
106 | octal digits; any non-digit terminates the sequence. If the |
107 | terminating character is @key{RET}, it serves only to terminate the | |
108 | sequence. Any other non-digit terminates the sequence and then acts | |
109 | as normal input---thus, @kbd{C-q 1 0 1 B} inserts @samp{AB}. | |
110 | ||
111 | The use of octal sequences is disabled in ordinary non-binary | |
112 | Overwrite mode, to give you a convenient way to insert a digit instead | |
113 | of overwriting with it. | |
6bf7aab6 DL |
114 | @end itemize |
115 | ||
b5d1e464 | 116 | @cindex 8-bit character codes |
6bf7aab6 | 117 | @noindent |
d3e94981 | 118 | When multibyte characters are enabled, if you specify a code in the |
093b0ab5 RS |
119 | range 0200 through 0377 octal, @kbd{C-q} assumes that you intend to |
120 | use some ISO 8859-@var{n} character set, and converts the specified | |
121 | code to the corresponding Emacs character code. @xref{Enabling | |
122 | Multibyte}. You select @emph{which} of the ISO 8859 character sets to | |
123 | use through your choice of language environment (@pxref{Language | |
124 | Environments}). | |
6bf7aab6 DL |
125 | |
126 | @vindex read-quoted-char-radix | |
127 | To use decimal or hexadecimal instead of octal, set the variable | |
128 | @code{read-quoted-char-radix} to 10 or 16. If the radix is greater than | |
129 | 10, some letters starting with @kbd{a} serve as part of a character | |
130 | code, just like digits. | |
131 | ||
132 | A numeric argument to @kbd{C-q} specifies how many copies of the | |
133 | quoted character should be inserted (@pxref{Arguments}). | |
134 | ||
135 | @findex newline | |
136 | @findex self-insert | |
137 | Customization information: @key{DEL} in most modes runs the command | |
138 | @code{delete-backward-char}; @key{RET} runs the command @code{newline}, and | |
139 | self-inserting printing characters run the command @code{self-insert}, | |
140 | which inserts whatever character was typed to invoke it. Some major modes | |
141 | rebind @key{DEL} to other commands. | |
142 | ||
143 | @node Moving Point | |
144 | @section Changing the Location of Point | |
145 | ||
146 | @cindex arrow keys | |
6bf7aab6 DL |
147 | @cindex moving point |
148 | @cindex movement | |
149 | @cindex cursor motion | |
150 | @cindex moving the cursor | |
151 | To do more than insert characters, you have to know how to move point | |
152 | (@pxref{Point}). The simplest way to do this is with arrow keys, or by | |
153 | clicking the left mouse button where you want to move to. | |
154 | ||
155 | There are also control and meta characters for cursor motion. Some | |
156 | are equivalent to the arrow keys (these date back to the days before | |
157 | terminals had arrow keys, and are usable on terminals which don't have | |
158 | them). Others do more sophisticated things. | |
159 | ||
160 | @kindex C-a | |
161 | @kindex C-e | |
162 | @kindex C-f | |
163 | @kindex C-b | |
164 | @kindex C-n | |
165 | @kindex C-p | |
166 | @kindex M-> | |
167 | @kindex M-< | |
168 | @kindex M-r | |
06a97e7d RS |
169 | @kindex LEFT |
170 | @kindex RIGHT | |
171 | @kindex UP | |
172 | @kindex DOWN | |
6bf7aab6 DL |
173 | @findex beginning-of-line |
174 | @findex end-of-line | |
175 | @findex forward-char | |
176 | @findex backward-char | |
177 | @findex next-line | |
178 | @findex previous-line | |
179 | @findex beginning-of-buffer | |
180 | @findex end-of-buffer | |
181 | @findex goto-char | |
182 | @findex goto-line | |
183 | @findex move-to-window-line | |
184 | @table @kbd | |
185 | @item C-a | |
186 | Move to the beginning of the line (@code{beginning-of-line}). | |
187 | @item C-e | |
188 | Move to the end of the line (@code{end-of-line}). | |
189 | @item C-f | |
06a97e7d RS |
190 | Move forward one character (@code{forward-char}). The right-arrow key |
191 | does the same thing. | |
6bf7aab6 | 192 | @item C-b |
06a97e7d RS |
193 | Move backward one character (@code{backward-char}). The left-arrow |
194 | key has the same effect. | |
6bf7aab6 DL |
195 | @item M-f |
196 | Move forward one word (@code{forward-word}). | |
197 | @item M-b | |
198 | Move backward one word (@code{backward-word}). | |
199 | @item C-n | |
200 | Move down one line, vertically (@code{next-line}). This command | |
201 | attempts to keep the horizontal position unchanged, so if you start in | |
06a97e7d RS |
202 | the middle of one line, you end in the middle of the next. The |
203 | down-arrow key does the same thing. | |
6bf7aab6 | 204 | @item C-p |
06a97e7d | 205 | Move up one line, vertically (@code{previous-line}). The up-arrow key |
21c983fc | 206 | has the same effect. |
6bf7aab6 DL |
207 | @item M-r |
208 | Move point to left margin, vertically centered in the window | |
209 | (@code{move-to-window-line}). Text does not move on the screen. | |
210 | ||
211 | A numeric argument says which screen line to place point on. It counts | |
212 | screen lines down from the top of the window (zero for the top line). A | |
213 | negative argument counts lines from the bottom (@minus{}1 for the bottom | |
214 | line). | |
215 | @item M-< | |
216 | Move to the top of the buffer (@code{beginning-of-buffer}). With | |
217 | numeric argument @var{n}, move to @var{n}/10 of the way from the top. | |
218 | @xref{Arguments}, for more information on numeric arguments.@refill | |
219 | @item M-> | |
220 | Move to the end of the buffer (@code{end-of-buffer}). | |
06a97e7d RS |
221 | @item C-v |
222 | Scroll the display one screen forward, and move point if necessary to put | |
223 | it on the screen (@code{scroll-up}). This doesn't always | |
224 | move point, but it is commonly used to do so. | |
225 | If your keyboard has a @key{PAGEDOWN} key, it does the same thing. | |
226 | ||
227 | Scrolling commands are further described in @ref{Scrolling}. | |
228 | @item M-v | |
229 | Scroll one screen backward, and move point if necessary to put it on | |
230 | the screen (@code{scroll-down}). This doesn't always move point, but | |
231 | it is commonly used to do so. The @key{PAGEUP} key has the same | |
232 | effect. | |
6bf7aab6 DL |
233 | @item M-x goto-char |
234 | Read a number @var{n} and move point to buffer position @var{n}. | |
235 | Position 1 is the beginning of the buffer. | |
236 | @item M-x goto-line | |
237 | Read a number @var{n} and move point to line number @var{n}. Line 1 | |
238 | is the beginning of the buffer. | |
239 | @item C-x C-n | |
240 | @findex set-goal-column | |
241 | @kindex C-x C-n | |
242 | Use the current column of point as the @dfn{semipermanent goal column} for | |
243 | @kbd{C-n} and @kbd{C-p} (@code{set-goal-column}). Henceforth, those | |
244 | commands always move to this column in each line moved into, or as | |
245 | close as possible given the contents of the line. This goal column remains | |
246 | in effect until canceled. | |
247 | @item C-u C-x C-n | |
248 | Cancel the goal column. Henceforth, @kbd{C-n} and @kbd{C-p} once | |
249 | again try to stick to a fixed horizontal position, as usual. | |
250 | @end table | |
251 | ||
252 | @vindex track-eol | |
253 | If you set the variable @code{track-eol} to a non-@code{nil} value, | |
015a26d7 | 254 | then @kbd{C-n} and @kbd{C-p}, when starting at the end of the line, move |
6bf7aab6 DL |
255 | to the end of another line. Normally, @code{track-eol} is @code{nil}. |
256 | @xref{Variables}, for how to set variables such as @code{track-eol}. | |
257 | ||
258 | @vindex next-line-add-newlines | |
36710aa6 GM |
259 | @kbd{C-n} normally gets an error when you use it on the last line of |
260 | the buffer (just as @kbd{C-p} gets an error on the first line). But | |
261 | if you set the variable @code{next-line-add-newlines} to a | |
262 | non-@code{nil} value, @kbd{C-n} on the last line of a buffer creates | |
263 | an additional line at the end and moves down onto it. | |
6bf7aab6 DL |
264 | |
265 | @node Erasing | |
266 | @section Erasing Text | |
267 | ||
268 | @table @kbd | |
269 | @item @key{DEL} | |
270 | Delete the character before point (@code{delete-backward-char}). | |
271 | @item C-d | |
272 | Delete the character after point (@code{delete-char}). | |
06a97e7d RS |
273 | @item @key{DELETE} |
274 | @itemx @key{BACKSPACE} | |
275 | One of these keys, whichever is the large key above the @key{RET} or | |
276 | @key{ENTER} key, deletes the character before point, like @key{DEL}. | |
277 | If that is @key{BACKSPACE}, and your keyboard also has @key{DELETE}, | |
278 | then @key{DELETE} deletes forwards, like @kbd{C-d}. | |
6bf7aab6 DL |
279 | @item C-k |
280 | Kill to the end of the line (@code{kill-line}). | |
281 | @item M-d | |
282 | Kill forward to the end of the next word (@code{kill-word}). | |
283 | @item M-@key{DEL} | |
284 | Kill back to the beginning of the previous word | |
285 | (@code{backward-kill-word}). | |
286 | @end table | |
287 | ||
288 | @cindex killing characters and lines | |
289 | @cindex deleting characters and lines | |
290 | @cindex erasing characters and lines | |
291 | You already know about the @key{DEL} key which deletes the character | |
292 | before point (that is, before the cursor). Another key, @kbd{Control-d} | |
293 | (@kbd{C-d} for short), deletes the character after point (that is, the | |
294 | character that the cursor is on). This shifts the rest of the text on | |
295 | the line to the left. If you type @kbd{C-d} at the end of a line, it | |
296 | joins together that line and the next line. | |
297 | ||
298 | To erase a larger amount of text, use the @kbd{C-k} key, which kills a | |
299 | line at a time. If you type @kbd{C-k} at the beginning or middle of a | |
300 | line, it kills all the text up to the end of the line. If you type | |
301 | @kbd{C-k} at the end of a line, it joins that line and the next line. | |
302 | ||
303 | @xref{Killing}, for more flexible ways of killing text. | |
304 | ||
305 | @node Undo | |
306 | @section Undoing Changes | |
307 | @cindex undo | |
308 | @cindex changes, undoing | |
309 | ||
310 | You can undo all the recent changes in the buffer text, up to a | |
311 | certain point. Each buffer records changes individually, and the undo | |
312 | command always applies to the current buffer. Usually each editing | |
313 | command makes a separate entry in the undo records, but some commands | |
314 | such as @code{query-replace} make many entries, and very simple commands | |
315 | such as self-inserting characters are often grouped to make undoing less | |
316 | tedious. | |
317 | ||
318 | @table @kbd | |
319 | @item C-x u | |
320 | Undo one batch of changes---usually, one command worth (@code{undo}). | |
321 | @item C-_ | |
322 | The same. | |
323 | @item C-u C-x u | |
324 | Undo one batch of changes in the region. | |
325 | @end table | |
326 | ||
327 | @kindex C-x u | |
328 | @kindex C-_ | |
329 | @findex undo | |
330 | The command @kbd{C-x u} or @kbd{C-_} is how you undo. The first time | |
331 | you give this command, it undoes the last change. Point moves back to | |
332 | where it was before the command that made the change. | |
333 | ||
334 | Consecutive repetitions of @kbd{C-_} or @kbd{C-x u} undo earlier and | |
335 | earlier changes, back to the limit of the undo information available. | |
336 | If all recorded changes have already been undone, the undo command | |
1ba2ce68 | 337 | displays an error message and does nothing. |
6bf7aab6 DL |
338 | |
339 | Any command other than an undo command breaks the sequence of undo | |
340 | commands. Starting from that moment, the previous undo commands become | |
341 | ordinary changes that you can undo. Thus, to redo changes you have | |
342 | undone, type @kbd{C-f} or any other command that will harmlessly break | |
343 | the sequence of undoing, then type more undo commands. | |
344 | ||
345 | @cindex selective undo | |
346 | @kindex C-u C-x u | |
347 | Ordinary undo applies to all changes made in the current buffer. You | |
348 | can also perform @dfn{selective undo}, limited to the current region. | |
349 | To do this, specify the region you want, then run the @code{undo} | |
350 | command with a prefix argument (the value does not matter): @kbd{C-u C-x | |
351 | u} or @kbd{C-u C-_}. This undoes the most recent change in the region. | |
352 | To undo further changes in the same region, repeat the @code{undo} | |
353 | command (no prefix argument is needed). In Transient Mark mode, any use | |
354 | of @code{undo} when there is an active region performs selective undo; | |
355 | you do not need a prefix argument. | |
356 | ||
357 | If you notice that a buffer has been modified accidentally, the | |
358 | easiest way to recover is to type @kbd{C-_} repeatedly until the stars | |
359 | disappear from the front of the mode line. At this time, all the | |
360 | modifications you made have been canceled. Whenever an undo command | |
361 | makes the stars disappear from the mode line, it means that the buffer | |
362 | contents are the same as they were when the file was last read in or | |
363 | saved. | |
364 | ||
365 | If you do not remember whether you changed the buffer deliberately, | |
366 | type @kbd{C-_} once. When you see the last change you made undone, you | |
367 | will see whether it was an intentional change. If it was an accident, | |
368 | leave it undone. If it was deliberate, redo the change as described | |
369 | above. | |
370 | ||
371 | Not all buffers record undo information. Buffers whose names start with | |
372 | spaces don't; these buffers are used internally by Emacs and its extensions | |
373 | to hold text that users don't normally look at or edit. | |
374 | ||
375 | You cannot undo mere cursor motion; only changes in the buffer | |
376 | contents save undo information. However, some cursor motion commands | |
377 | set the mark, so if you use these commands from time to time, you can | |
378 | move back to the neighborhoods you have moved through by popping the | |
379 | mark ring (@pxref{Mark Ring}). | |
380 | ||
381 | @vindex undo-limit | |
382 | @vindex undo-strong-limit | |
383 | @cindex undo limit | |
384 | When the undo information for a buffer becomes too large, Emacs | |
385 | discards the oldest undo information from time to time (during garbage | |
386 | collection). You can specify how much undo information to keep by | |
387 | setting two variables: @code{undo-limit} and @code{undo-strong-limit}. | |
388 | Their values are expressed in units of bytes of space. | |
389 | ||
390 | The variable @code{undo-limit} sets a soft limit: Emacs keeps undo | |
391 | data for enough commands to reach this size, and perhaps exceed it, but | |
392 | does not keep data for any earlier commands beyond that. Its default | |
393 | value is 20000. The variable @code{undo-strong-limit} sets a stricter | |
394 | limit: the command which pushes the size past this amount is itself | |
395 | forgotten. Its default value is 30000. | |
396 | ||
397 | Regardless of the values of those variables, the most recent change is | |
398 | never discarded, so there is no danger that garbage collection occurring | |
399 | right after an unintentional large change might prevent you from undoing | |
400 | it. | |
401 | ||
402 | The reason the @code{undo} command has two keys, @kbd{C-x u} and | |
403 | @kbd{C-_}, set up to run it is that it is worthy of a single-character | |
404 | key, but on some keyboards it is not obvious how to type @kbd{C-_}. | |
405 | @kbd{C-x u} is an alternative you can type straightforwardly on any | |
406 | terminal. | |
407 | ||
408 | @node Basic Files | |
409 | @section Files | |
410 | ||
411 | The commands described above are sufficient for creating and altering | |
412 | text in an Emacs buffer; the more advanced Emacs commands just make | |
413 | things easier. But to keep any text permanently you must put it in a | |
414 | @dfn{file}. Files are named units of text which are stored by the | |
415 | operating system for you to retrieve later by name. To look at or use | |
416 | the contents of a file in any way, including editing the file with | |
417 | Emacs, you must specify the file name. | |
418 | ||
419 | Consider a file named @file{/usr/rms/foo.c}. In Emacs, to begin editing | |
420 | this file, type | |
421 | ||
422 | @example | |
423 | C-x C-f /usr/rms/foo.c @key{RET} | |
424 | @end example | |
425 | ||
426 | @noindent | |
427 | Here the file name is given as an @dfn{argument} to the command @kbd{C-x | |
428 | C-f} (@code{find-file}). That command uses the @dfn{minibuffer} to | |
429 | read the argument, and you type @key{RET} to terminate the argument | |
430 | (@pxref{Minibuffer}).@refill | |
431 | ||
432 | Emacs obeys the command by @dfn{visiting} the file: creating a buffer, | |
433 | copying the contents of the file into the buffer, and then displaying | |
434 | the buffer for you to edit. If you alter the text, you can @dfn{save} | |
435 | the new text in the file by typing @kbd{C-x C-s} (@code{save-buffer}). | |
436 | This makes the changes permanent by copying the altered buffer contents | |
437 | back into the file @file{/usr/rms/foo.c}. Until you save, the changes | |
438 | exist only inside Emacs, and the file @file{foo.c} is unaltered. | |
439 | ||
440 | To create a file, just visit the file with @kbd{C-x C-f} as if it | |
441 | already existed. This creates an empty buffer in which you can insert | |
442 | the text you want to put in the file. The file is actually created when | |
443 | you save this buffer with @kbd{C-x C-s}. | |
444 | ||
445 | Of course, there is a lot more to learn about using files. @xref{Files}. | |
446 | ||
447 | @node Basic Help | |
448 | @section Help | |
449 | ||
450 | @cindex getting help with keys | |
451 | If you forget what a key does, you can find out with the Help | |
452 | character, which is @kbd{C-h} (or @key{F1}, which is an alias for | |
453 | @kbd{C-h}). Type @kbd{C-h k} followed by the key you want to know | |
454 | about; for example, @kbd{C-h k C-n} tells you all about what @kbd{C-n} | |
455 | does. @kbd{C-h} is a prefix key; @kbd{C-h k} is just one of its | |
456 | subcommands (the command @code{describe-key}). The other subcommands of | |
457 | @kbd{C-h} provide different kinds of help. Type @kbd{C-h} twice to get | |
458 | a description of all the help facilities. @xref{Help}.@refill | |
459 | ||
460 | @node Blank Lines | |
461 | @section Blank Lines | |
462 | ||
463 | @cindex inserting blank lines | |
464 | @cindex deleting blank lines | |
465 | Here are special commands and techniques for putting in and taking out | |
466 | blank lines. | |
467 | ||
468 | @c widecommands | |
469 | @table @kbd | |
470 | @item C-o | |
471 | Insert one or more blank lines after the cursor (@code{open-line}). | |
472 | @item C-x C-o | |
473 | Delete all but one of many consecutive blank lines | |
474 | (@code{delete-blank-lines}). | |
475 | @end table | |
476 | ||
477 | @kindex C-o | |
478 | @kindex C-x C-o | |
479 | @cindex blank lines | |
480 | @findex open-line | |
481 | @findex delete-blank-lines | |
482 | When you want to insert a new line of text before an existing line, you | |
483 | can do it by typing the new line of text, followed by @key{RET}. | |
484 | However, it may be easier to see what you are doing if you first make a | |
485 | blank line and then insert the desired text into it. This is easy to do | |
486 | using the key @kbd{C-o} (@code{open-line}), which inserts a newline | |
487 | after point but leaves point in front of the newline. After @kbd{C-o}, | |
488 | type the text for the new line. @kbd{C-o F O O} has the same effect as | |
489 | @w{@kbd{F O O @key{RET}}}, except for the final location of point. | |
490 | ||
491 | You can make several blank lines by typing @kbd{C-o} several times, or | |
492 | by giving it a numeric argument to tell it how many blank lines to make. | |
493 | @xref{Arguments}, for how. If you have a fill prefix, then @kbd{C-o} | |
494 | command inserts the fill prefix on the new line, when you use it at the | |
495 | beginning of a line. @xref{Fill Prefix}. | |
496 | ||
497 | The easy way to get rid of extra blank lines is with the command | |
498 | @kbd{C-x C-o} (@code{delete-blank-lines}). @kbd{C-x C-o} in a run of | |
499 | several blank lines deletes all but one of them. @kbd{C-x C-o} on a | |
500 | solitary blank line deletes that blank line. When point is on a | |
501 | nonblank line, @kbd{C-x C-o} deletes any blank lines following that | |
502 | nonblank line. | |
503 | ||
504 | @node Continuation Lines | |
505 | @section Continuation Lines | |
506 | ||
507 | @cindex continuation line | |
508 | @cindex wrapping | |
509 | @cindex line wrapping | |
510 | If you add too many characters to one line without breaking it with | |
093b0ab5 RS |
511 | @key{RET}, the line grows to occupy two (or more) lines on the screen. |
512 | On graphical displays, Emacs indicates line wrapping with small bent | |
513 | arrows in the fringes to the left and right of the window. On | |
514 | text-only terminals, Emacs displays a @samp{\} character at the right | |
515 | margin of a screen line if it is not the last in its text line. This | |
516 | @samp{\} character says that the following screen line is not really a | |
517 | distinct line in the text, just a @dfn{continuation} of a line too | |
518 | long to fit the screen. Continuation is also called @dfn{line | |
519 | wrapping}. | |
520 | ||
521 | When line wrapping occurs before a character that is wider than one | |
522 | column, some columns at the end of the previous screen line may be | |
523 | ``empty.'' In this case, Emacs displays additional @samp{\} | |
524 | characters in the ``empty'' columns, just before the @samp{\} | |
525 | character that indicates continuation. | |
6bf7aab6 DL |
526 | |
527 | Sometimes it is nice to have Emacs insert newlines automatically when | |
528 | a line gets too long. Continuation on the screen does not do that. Use | |
529 | Auto Fill mode (@pxref{Filling}) if that's what you want. | |
530 | ||
531 | @vindex truncate-lines | |
532 | @cindex truncation | |
533 | As an alternative to continuation, Emacs can display long lines by | |
457b792c GM |
534 | @dfn{truncation}. This means that all the characters that do not fit |
535 | in the width of the screen or window do not appear at all. They | |
536 | remain in the buffer, temporarily invisible. On terminals, @samp{$} | |
093b0ab5 RS |
537 | in the last column informs you that the line has been truncated on the |
538 | display. On window systems, a small straight arrow in the fringe to | |
539 | the right of the window indicates a truncated line. | |
6bf7aab6 | 540 | |
093b0ab5 | 541 | @findex toggle-truncate-lines |
6bf7aab6 DL |
542 | Truncation instead of continuation happens whenever horizontal |
543 | scrolling is in use, and optionally in all side-by-side windows | |
093b0ab5 RS |
544 | (@pxref{Windows}). You can enable or disable truncation for a |
545 | particular buffer with the command @kbd{M-x toggle-truncate-lines}. | |
93bea98b | 546 | |
af6eba70 | 547 | @xref{Display Custom}, for additional variables that affect how text is |
6bf7aab6 DL |
548 | displayed. |
549 | ||
550 | @node Position Info | |
551 | @section Cursor Position Information | |
552 | ||
553 | Here are commands to get information about the size and position of | |
554 | parts of the buffer, and to count lines. | |
555 | ||
556 | @table @kbd | |
557 | @item M-x what-page | |
093b0ab5 | 558 | Display the page number of point, and the line number within the page. |
6bf7aab6 | 559 | @item M-x what-line |
093b0ab5 | 560 | Display the line number of point in the buffer. |
6bf7aab6 | 561 | @item M-x line-number-mode |
67675c0f DL |
562 | @itemx M-x column-number-mode |
563 | Toggle automatic display of current line number or column number. | |
564 | @xref{Optional Mode Line}. | |
6bf7aab6 | 565 | @item M-= |
093b0ab5 | 566 | Display the number of lines in the current region (@code{count-lines-region}). |
6bf7aab6 DL |
567 | @xref{Mark}, for information about the region. |
568 | @item C-x = | |
093b0ab5 | 569 | Display the character code of character after point, character position of |
6bf7aab6 | 570 | point, and column of point (@code{what-cursor-position}). |
67675c0f | 571 | @item M-x hl-line-mode |
83440f52 EZ |
572 | Enable or disable highlighting of the current line. @xref{Cursor |
573 | Display}. | |
6bf7aab6 DL |
574 | @end table |
575 | ||
576 | @findex what-page | |
577 | @findex what-line | |
578 | @cindex line number commands | |
579 | @cindex location of point | |
580 | @cindex cursor location | |
581 | @cindex point location | |
582 | There are two commands for working with line numbers. @kbd{M-x | |
583 | what-line} computes the current line number and displays it in the echo | |
584 | area. To go to a given line by number, use @kbd{M-x goto-line}; it | |
585 | prompts you for the number. These line numbers count from one at the | |
586 | beginning of the buffer. | |
587 | ||
9acb8eec | 588 | You can also see the current line number in the mode line; see @ref{Mode |
6bf7aab6 DL |
589 | Line}. If you narrow the buffer, then the line number in the mode line |
590 | is relative to the accessible portion (@pxref{Narrowing}). By contrast, | |
591 | @code{what-line} shows both the line number relative to the narrowed | |
592 | region and the line number relative to the whole buffer. | |
593 | ||
9acb8eec | 594 | @kbd{M-x what-page} counts pages from the beginning of the file, and |
1ba2ce68 RS |
595 | counts lines within the page, showing both numbers in the echo area. |
596 | @xref{Pages}. | |
6bf7aab6 DL |
597 | |
598 | @kindex M-= | |
599 | @findex count-lines-region | |
600 | While on this subject, we might as well mention @kbd{M-=} (@code{count-lines-region}), | |
1ba2ce68 | 601 | which displays the number of lines in the region (@pxref{Mark}). |
6bf7aab6 DL |
602 | @xref{Pages}, for the command @kbd{C-x l} which counts the lines in the |
603 | current page. | |
604 | ||
605 | @kindex C-x = | |
606 | @findex what-cursor-position | |
607 | The command @kbd{C-x =} (@code{what-cursor-position}) can be used to find out | |
608 | the column that the cursor is in, and other miscellaneous information about | |
1ba2ce68 | 609 | point. It displays a line in the echo area that looks like this: |
6bf7aab6 DL |
610 | |
611 | @smallexample | |
612 | Char: c (0143, 99, 0x63) point=21044 of 26883(78%) column 53 | |
613 | @end smallexample | |
614 | ||
615 | @noindent | |
616 | (In fact, this is the output produced when point is before the | |
617 | @samp{column} in the example.) | |
618 | ||
619 | The four values after @samp{Char:} describe the character that follows | |
620 | point, first by showing it and then by giving its character code in | |
621 | octal, decimal and hex. For a non-ASCII multibyte character, these are | |
622 | followed by @samp{ext} and the character's representation, in hex, in | |
623 | the buffer's coding system, if that coding system encodes the character | |
624 | safely and with a single byte (@pxref{Coding Systems}). If the | |
625 | character's encoding is longer than one byte, Emacs shows @samp{ext ...}. | |
626 | ||
627 | @samp{point=} is followed by the position of point expressed as a character | |
628 | count. The front of the buffer counts as position 1, one character later | |
629 | as 2, and so on. The next, larger, number is the total number of characters | |
630 | in the buffer. Afterward in parentheses comes the position expressed as a | |
631 | percentage of the total size. | |
632 | ||
633 | @samp{column} is followed by the horizontal position of point, in | |
634 | columns from the left edge of the window. | |
635 | ||
636 | If the buffer has been narrowed, making some of the text at the | |
1ba2ce68 | 637 | beginning and the end temporarily inaccessible, @kbd{C-x =} displays |
6bf7aab6 DL |
638 | additional text describing the currently accessible range. For example, it |
639 | might display this: | |
640 | ||
641 | @smallexample | |
642 | Char: C (0103, 67, 0x43) point=252 of 889(28%) <231 - 599> column 0 | |
643 | @end smallexample | |
644 | ||
645 | @noindent | |
646 | where the two extra numbers give the smallest and largest character | |
647 | position that point is allowed to assume. The characters between those | |
648 | two positions are the accessible ones. @xref{Narrowing}. | |
649 | ||
650 | If point is at the end of the buffer (or the end of the accessible | |
651 | part), the @w{@kbd{C-x =}} output does not describe a character after | |
652 | point. The output might look like this: | |
653 | ||
654 | @smallexample | |
655 | point=26957 of 26956(100%) column 0 | |
656 | @end smallexample | |
657 | ||
658 | @w{@kbd{C-u C-x =}} displays additional information about a character, | |
659 | in place of the buffer coordinates and column: the character set name | |
660 | and the codes that identify the character within that character set; | |
661 | ASCII characters are identified as belonging to the @code{ASCII} | |
662 | character set. In addition, the full character encoding, even if it | |
663 | takes more than a single byte, is shown after @samp{ext}. Here's an | |
664 | example for a Latin-1 character A with a grave accent in a buffer whose | |
665 | coding system is iso-2022-7bit@footnote{On terminals that support | |
666 | Latin-1 characters, the character shown after @samp{Char:} is displayed | |
667 | as the actual glyph of A with grave accent.}: | |
668 | ||
9acb8eec | 669 | @smallexample |
6bf7aab6 | 670 | Char: @`A (04300, 2240, 0x8c0, ext ESC , A @@) (latin-iso8859-1 64) |
9acb8eec | 671 | @end smallexample |
6bf7aab6 DL |
672 | |
673 | @node Arguments | |
674 | @section Numeric Arguments | |
675 | @cindex numeric arguments | |
676 | @cindex prefix arguments | |
4946337d | 677 | @cindex arguments to commands |
6bf7aab6 DL |
678 | |
679 | In mathematics and computer usage, the word @dfn{argument} means | |
680 | ``data provided to a function or operation.'' You can give any Emacs | |
681 | command a @dfn{numeric argument} (also called a @dfn{prefix argument}). | |
682 | Some commands interpret the argument as a repetition count. For | |
683 | example, @kbd{C-f} with an argument of ten moves forward ten characters | |
684 | instead of one. With these commands, no argument is equivalent to an | |
685 | argument of one. Negative arguments tell most such commands to move or | |
686 | act in the opposite direction. | |
687 | ||
688 | @kindex M-1 | |
689 | @kindex M-@t{-} | |
690 | @findex digit-argument | |
691 | @findex negative-argument | |
692 | If your terminal keyboard has a @key{META} key, the easiest way to | |
693 | specify a numeric argument is to type digits and/or a minus sign while | |
694 | holding down the @key{META} key. For example, | |
a1f6ea55 | 695 | |
6bf7aab6 DL |
696 | @example |
697 | M-5 C-n | |
698 | @end example | |
a1f6ea55 | 699 | |
6bf7aab6 DL |
700 | @noindent |
701 | would move down five lines. The characters @kbd{Meta-1}, @kbd{Meta-2}, | |
702 | and so on, as well as @kbd{Meta--}, do this because they are keys bound | |
703 | to commands (@code{digit-argument} and @code{negative-argument}) that | |
a1f6ea55 EZ |
704 | are defined to contribute to an argument for the next command. |
705 | @kbd{Meta--} without digits normally means @minus{}1. Digits and | |
706 | @kbd{-} modified with Control, or Control and Meta, also specify numeric | |
707 | arguments. | |
6bf7aab6 DL |
708 | |
709 | @kindex C-u | |
710 | @findex universal-argument | |
711 | Another way of specifying an argument is to use the @kbd{C-u} | |
712 | (@code{universal-argument}) command followed by the digits of the | |
713 | argument. With @kbd{C-u}, you can type the argument digits without | |
714 | holding down modifier keys; @kbd{C-u} works on all terminals. To type a | |
715 | negative argument, type a minus sign after @kbd{C-u}. Just a minus sign | |
716 | without digits normally means @minus{}1. | |
717 | ||
718 | @kbd{C-u} followed by a character which is neither a digit nor a minus | |
719 | sign has the special meaning of ``multiply by four.'' It multiplies the | |
720 | argument for the next command by four. @kbd{C-u} twice multiplies it by | |
721 | sixteen. Thus, @kbd{C-u C-u C-f} moves forward sixteen characters. This | |
722 | is a good way to move forward ``fast,'' since it moves about 1/5 of a line | |
723 | in the usual size screen. Other useful combinations are @kbd{C-u C-n}, | |
724 | @kbd{C-u C-u C-n} (move down a good fraction of a screen), @kbd{C-u C-u | |
725 | C-o} (make ``a lot'' of blank lines), and @kbd{C-u C-k} (kill four | |
726 | lines).@refill | |
727 | ||
728 | Some commands care only about whether there is an argument, and not about | |
729 | its value. For example, the command @kbd{M-q} (@code{fill-paragraph}) with | |
730 | no argument fills text; with an argument, it justifies the text as well. | |
731 | (@xref{Filling}, for more information on @kbd{M-q}.) Plain @kbd{C-u} is a | |
732 | handy way of providing an argument for such commands. | |
733 | ||
734 | Some commands use the value of the argument as a repeat count, but do | |
735 | something peculiar when there is no argument. For example, the command | |
736 | @kbd{C-k} (@code{kill-line}) with argument @var{n} kills @var{n} lines, | |
737 | including their terminating newlines. But @kbd{C-k} with no argument is | |
738 | special: it kills the text up to the next newline, or, if point is right at | |
739 | the end of the line, it kills the newline itself. Thus, two @kbd{C-k} | |
740 | commands with no arguments can kill a nonblank line, just like @kbd{C-k} | |
741 | with an argument of one. (@xref{Killing}, for more information on | |
742 | @kbd{C-k}.)@refill | |
743 | ||
744 | A few commands treat a plain @kbd{C-u} differently from an ordinary | |
745 | argument. A few others may treat an argument of just a minus sign | |
746 | differently from an argument of @minus{}1. These unusual cases are | |
747 | described when they come up; they are always for reasons of convenience | |
748 | of use of the individual command. | |
749 | ||
750 | You can use a numeric argument to insert multiple copies of a | |
751 | character. This is straightforward unless the character is a digit; for | |
752 | example, @kbd{C-u 6 4 a} inserts 64 copies of the character @samp{a}. | |
753 | But this does not work for inserting digits; @kbd{C-u 6 4 1} specifies | |
754 | an argument of 641, rather than inserting anything. To separate the | |
755 | digit to insert from the argument, type another @kbd{C-u}; for example, | |
756 | @kbd{C-u 6 4 C-u 1} does insert 64 copies of the character @samp{1}. | |
757 | ||
758 | We use the term ``prefix argument'' as well as ``numeric argument'' to | |
759 | emphasize that you type the argument before the command, and to | |
760 | distinguish these arguments from minibuffer arguments that come after | |
761 | the command. | |
762 | ||
763 | @node Repeating | |
764 | @section Repeating a Command | |
765 | @cindex repeating a command | |
766 | ||
9b3ae7e4 RS |
767 | Many simple commands, such as those invoked with a single key or |
768 | with @kbd{M-x @var{command-name} @key{RET}}, can be repeated by | |
769 | invoking them with a numeric argument that serves as a repeat count | |
770 | (@pxref{Arguments}). However, if the command you want to repeat | |
771 | prompts for some input, or uses a numeric argument in another way, | |
772 | repetition using a numeric argument might be problematical. | |
68b7eaa9 | 773 | |
6bf7aab6 DL |
774 | @kindex C-x z |
775 | @findex repeat | |
776 | The command @kbd{C-x z} (@code{repeat}) provides another way to repeat | |
777 | an Emacs command many times. This command repeats the previous Emacs | |
778 | command, whatever that was. Repeating a command uses the same arguments | |
779 | that were used before; it does not read new arguments each time. | |
780 | ||
781 | To repeat the command more than once, type additional @kbd{z}'s: each | |
782 | @kbd{z} repeats the command one more time. Repetition ends when you | |
783 | type a character other than @kbd{z}, or press a mouse button. | |
784 | ||
785 | For example, suppose you type @kbd{C-u 2 0 C-d} to delete 20 | |
786 | characters. You can repeat that command (including its argument) three | |
787 | additional times, to delete a total of 80 characters, by typing @kbd{C-x | |
788 | z z z}. The first @kbd{C-x z} repeats the command once, and each | |
789 | subsequent @kbd{z} repeats it once again. | |
790 |