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6bf7aab6 | 1 | @c This is part of the Emacs manual. |
b65d8176 TTN |
2 | @c Copyright (C) 1985, 1986, 1987, 1993, 1994, 1995, 1997, 2000, 2001, |
3 | @c 2002, 2003, 2004, 2005 Free Software Foundation, Inc. | |
6bf7aab6 DL |
4 | @c See file emacs.texi for copying conditions. |
5 | @node Basic, Minibuffer, Exiting, Top | |
6 | @chapter Basic Editing Commands | |
7 | ||
8 | @kindex C-h t | |
9 | @findex help-with-tutorial | |
10 | We now give the basics of how to enter text, make corrections, and | |
11 | save the text in a file. If this material is new to you, you might | |
12 | learn it more easily by running the Emacs learn-by-doing tutorial. To | |
13 | use the tutorial, run Emacs and type @kbd{Control-h t} | |
14 | (@code{help-with-tutorial}). | |
15 | ||
16 | To clear the screen and redisplay, type @kbd{C-l} (@code{recenter}). | |
17 | ||
18 | @menu | |
19 | ||
20 | * Inserting Text:: Inserting text by simply typing it. | |
21 | * Moving Point:: How to move the cursor to the place where you want to | |
22 | change something. | |
23 | * Erasing:: Deleting and killing text. | |
24 | * Undo:: Undoing recent changes in the text. | |
25 | * Files: Basic Files. Visiting, creating, and saving files. | |
26 | * Help: Basic Help. Asking what a character does. | |
27 | * Blank Lines:: Commands to make or delete blank lines. | |
28 | * Continuation Lines:: Lines too wide for the screen. | |
29 | * Position Info:: What page, line, row, or column is point on? | |
30 | * Arguments:: Numeric arguments for repeating a command. | |
31 | * Repeating:: A short-cut for repeating the previous command. | |
32 | @end menu | |
33 | ||
34 | @node Inserting Text | |
35 | @section Inserting Text | |
36 | ||
37 | @cindex insertion | |
38 | @cindex graphic characters | |
39 | To insert printing characters into the text you are editing, just type | |
40 | them. This inserts the characters you type into the buffer at the | |
41 | cursor (that is, at @dfn{point}; @pxref{Point}). The cursor moves | |
42 | forward, and any text after the cursor moves forward too. If the text | |
43 | in the buffer is @samp{FOOBAR}, with the cursor before the @samp{B}, | |
44 | then if you type @kbd{XX}, you get @samp{FOOXXBAR}, with the cursor | |
45 | still before the @samp{B}. | |
46 | ||
06a97e7d RS |
47 | To @dfn{delete} text you have just inserted, use the large key |
48 | labeled @key{DEL}, @key{BACKSPACE} or @key{DELETE} which is a short | |
49 | distance above the @key{RET} or @key{ENTER} key. This is the key you | |
9ab48fa6 | 50 | normally use, outside Emacs, for erasing the last character that you |
bf1a7e14 RS |
51 | typed. Regardless of the label on that key, Emacs thinks of it as |
52 | @key{DEL}, and that's what we call it in this manual. | |
6bf7aab6 | 53 | |
06a97e7d RS |
54 | The @key{DEL} key deletes the character @emph{before} the cursor. |
55 | As a consequence, the cursor and all the characters after it move | |
56 | backwards. If you type a printing character and then type @key{DEL}, | |
57 | they cancel out. | |
58 | ||
9ab48fa6 RS |
59 | On most computers, Emacs recognizes automatically which key ought to |
60 | be @key{DEL}, and sets it up that way. But in some cases, especially | |
61 | with text-only terminals, you will need to tell Emacs which key to use | |
62 | for that purpose. If the large key not far above the @key{RET} or | |
63 | @key{ENTER} key doesn't delete backwards, you need to do this. | |
82f6ab38 | 64 | @xref{DEL Does Not Delete}, for an explanation of how. |
9ab48fa6 | 65 | |
83b344c5 RS |
66 | Most PC keyboards have both a @key{BACKSPACE} key a short ways above |
67 | @key{RET} or @key{ENTER}, and a @key{DELETE} key elsewhere. On these | |
68 | keyboards, Emacs supports when possible the usual convention that the | |
69 | @key{BACKSPACE} key deletes backwards (it is @key{DEL}), while the | |
70 | @key{DELETE} key deletes ``forwards,'' deleting the character after | |
71 | point, the one underneath the cursor, like @kbd{C-d} (see below). | |
06a97e7d | 72 | |
6bf7aab6 DL |
73 | @kindex RET |
74 | @cindex newline | |
75 | To end a line and start typing a new one, type @key{RET}. This | |
76 | inserts a newline character in the buffer. If point is in the middle of | |
1b53c26e | 77 | a line, the effect is to split the line. Typing @key{DEL} when the cursor is |
6bf7aab6 DL |
78 | at the beginning of a line deletes the preceding newline, thus joining |
79 | the line with the preceding line. | |
80 | ||
81 | Emacs can split lines automatically when they become too long, if you | |
82 | turn on a special minor mode called @dfn{Auto Fill} mode. | |
83 | @xref{Filling}, for how to use Auto Fill mode. | |
84 | ||
85 | If you prefer to have text characters replace (overwrite) existing | |
86 | text rather than shove it to the right, you can enable Overwrite mode, | |
87 | a minor mode. @xref{Minor Modes}. | |
88 | ||
89 | @cindex quoting | |
90 | @kindex C-q | |
91 | @findex quoted-insert | |
92 | Direct insertion works for printing characters and @key{SPC}, but other | |
93 | characters act as editing commands and do not insert themselves. If you | |
94 | need to insert a control character or a character whose code is above 200 | |
95 | octal, you must @dfn{quote} it by typing the character @kbd{Control-q} | |
96 | (@code{quoted-insert}) first. (This character's name is normally written | |
97 | @kbd{C-q} for short.) There are two ways to use @kbd{C-q}:@refill | |
98 | ||
99 | @itemize @bullet | |
100 | @item | |
101 | @kbd{C-q} followed by any non-graphic character (even @kbd{C-g}) | |
102 | inserts that character. | |
103 | ||
104 | @item | |
105 | @kbd{C-q} followed by a sequence of octal digits inserts the character | |
106 | with the specified octal character code. You can use any number of | |
9acb8eec RS |
107 | octal digits; any non-digit terminates the sequence. If the |
108 | terminating character is @key{RET}, it serves only to terminate the | |
109 | sequence. Any other non-digit terminates the sequence and then acts | |
110 | as normal input---thus, @kbd{C-q 1 0 1 B} inserts @samp{AB}. | |
111 | ||
112 | The use of octal sequences is disabled in ordinary non-binary | |
113 | Overwrite mode, to give you a convenient way to insert a digit instead | |
114 | of overwriting with it. | |
6bf7aab6 DL |
115 | @end itemize |
116 | ||
b5d1e464 | 117 | @cindex 8-bit character codes |
6bf7aab6 | 118 | @noindent |
d3e94981 | 119 | When multibyte characters are enabled, if you specify a code in the |
093b0ab5 RS |
120 | range 0200 through 0377 octal, @kbd{C-q} assumes that you intend to |
121 | use some ISO 8859-@var{n} character set, and converts the specified | |
122 | code to the corresponding Emacs character code. @xref{Enabling | |
123 | Multibyte}. You select @emph{which} of the ISO 8859 character sets to | |
124 | use through your choice of language environment (@pxref{Language | |
125 | Environments}). | |
6bf7aab6 DL |
126 | |
127 | @vindex read-quoted-char-radix | |
128 | To use decimal or hexadecimal instead of octal, set the variable | |
129 | @code{read-quoted-char-radix} to 10 or 16. If the radix is greater than | |
130 | 10, some letters starting with @kbd{a} serve as part of a character | |
131 | code, just like digits. | |
132 | ||
133 | A numeric argument to @kbd{C-q} specifies how many copies of the | |
134 | quoted character should be inserted (@pxref{Arguments}). | |
135 | ||
136 | @findex newline | |
137 | @findex self-insert | |
138 | Customization information: @key{DEL} in most modes runs the command | |
139 | @code{delete-backward-char}; @key{RET} runs the command @code{newline}, and | |
140 | self-inserting printing characters run the command @code{self-insert}, | |
141 | which inserts whatever character was typed to invoke it. Some major modes | |
142 | rebind @key{DEL} to other commands. | |
143 | ||
144 | @node Moving Point | |
145 | @section Changing the Location of Point | |
146 | ||
147 | @cindex arrow keys | |
6bf7aab6 DL |
148 | @cindex moving point |
149 | @cindex movement | |
150 | @cindex cursor motion | |
151 | @cindex moving the cursor | |
152 | To do more than insert characters, you have to know how to move point | |
153 | (@pxref{Point}). The simplest way to do this is with arrow keys, or by | |
154 | clicking the left mouse button where you want to move to. | |
155 | ||
156 | There are also control and meta characters for cursor motion. Some | |
157 | are equivalent to the arrow keys (these date back to the days before | |
158 | terminals had arrow keys, and are usable on terminals which don't have | |
159 | them). Others do more sophisticated things. | |
160 | ||
161 | @kindex C-a | |
162 | @kindex C-e | |
163 | @kindex C-f | |
164 | @kindex C-b | |
165 | @kindex C-n | |
166 | @kindex C-p | |
167 | @kindex M-> | |
168 | @kindex M-< | |
169 | @kindex M-r | |
06a97e7d RS |
170 | @kindex LEFT |
171 | @kindex RIGHT | |
172 | @kindex UP | |
173 | @kindex DOWN | |
c7bda15b | 174 | @findex move-beginning-of-line |
aa3dd3b5 | 175 | @findex move-end-of-line |
6bf7aab6 DL |
176 | @findex forward-char |
177 | @findex backward-char | |
178 | @findex next-line | |
179 | @findex previous-line | |
180 | @findex beginning-of-buffer | |
181 | @findex end-of-buffer | |
182 | @findex goto-char | |
183 | @findex goto-line | |
184 | @findex move-to-window-line | |
185 | @table @kbd | |
186 | @item C-a | |
c7bda15b | 187 | Move to the beginning of the line (@code{move-beginning-of-line}). |
6bf7aab6 | 188 | @item C-e |
aa3dd3b5 | 189 | Move to the end of the line (@code{move-end-of-line}). |
6bf7aab6 | 190 | @item C-f |
06a97e7d RS |
191 | Move forward one character (@code{forward-char}). The right-arrow key |
192 | does the same thing. | |
6bf7aab6 | 193 | @item C-b |
06a97e7d RS |
194 | Move backward one character (@code{backward-char}). The left-arrow |
195 | key has the same effect. | |
6bf7aab6 DL |
196 | @item M-f |
197 | Move forward one word (@code{forward-word}). | |
198 | @item M-b | |
199 | Move backward one word (@code{backward-word}). | |
200 | @item C-n | |
201 | Move down one line, vertically (@code{next-line}). This command | |
202 | attempts to keep the horizontal position unchanged, so if you start in | |
06a97e7d RS |
203 | the middle of one line, you end in the middle of the next. The |
204 | down-arrow key does the same thing. | |
6bf7aab6 | 205 | @item C-p |
06a97e7d | 206 | Move up one line, vertically (@code{previous-line}). The up-arrow key |
21c983fc | 207 | has the same effect. |
6bf7aab6 DL |
208 | @item M-r |
209 | Move point to left margin, vertically centered in the window | |
210 | (@code{move-to-window-line}). Text does not move on the screen. | |
211 | ||
212 | A numeric argument says which screen line to place point on. It counts | |
213 | screen lines down from the top of the window (zero for the top line). A | |
214 | negative argument counts lines from the bottom (@minus{}1 for the bottom | |
215 | line). | |
216 | @item M-< | |
217 | Move to the top of the buffer (@code{beginning-of-buffer}). With | |
218 | numeric argument @var{n}, move to @var{n}/10 of the way from the top. | |
219 | @xref{Arguments}, for more information on numeric arguments.@refill | |
220 | @item M-> | |
221 | Move to the end of the buffer (@code{end-of-buffer}). | |
06a97e7d | 222 | @item C-v |
1b53c26e RS |
223 | @itemx @key{PAGEDOWN} |
224 | @itemx @key{PRIOR} | |
225 | Scroll the display one screen forward, and move point if necessary to | |
226 | put it on the screen (@code{scroll-up}). This doesn't always move | |
227 | point, but it is commonly used to do so. If your keyboard has a | |
228 | @key{PAGEDOWN} or @key{PRIOR} key, it does the same thing. | |
06a97e7d RS |
229 | |
230 | Scrolling commands are further described in @ref{Scrolling}. | |
231 | @item M-v | |
1b53c26e RS |
232 | @itemx @key{PAGEUP} |
233 | @itemx @key{NEXT} | |
06a97e7d RS |
234 | Scroll one screen backward, and move point if necessary to put it on |
235 | the screen (@code{scroll-down}). This doesn't always move point, but | |
1b53c26e RS |
236 | it is commonly used to do so. If your keyboard has a @key{PAGEUP} or |
237 | @key{NEXT} key, it does the same thing. | |
6bf7aab6 DL |
238 | @item M-x goto-char |
239 | Read a number @var{n} and move point to buffer position @var{n}. | |
240 | Position 1 is the beginning of the buffer. | |
33e54c87 | 241 | @item M-g M-g |
706f4350 | 242 | @itemx M-g g |
33e54c87 | 243 | @itemx M-x goto-line |
48c13f3e LT |
244 | Read a number @var{n} and move point to the beginning of line number |
245 | @var{n}. Line 1 is the beginning of the buffer. If point is on or | |
246 | just after a number, then that is the default for @var{n}, if you just | |
247 | press @key{RET} with an empty minibuffer. | |
6bf7aab6 DL |
248 | @item C-x C-n |
249 | @findex set-goal-column | |
250 | @kindex C-x C-n | |
251 | Use the current column of point as the @dfn{semipermanent goal column} for | |
252 | @kbd{C-n} and @kbd{C-p} (@code{set-goal-column}). Henceforth, those | |
253 | commands always move to this column in each line moved into, or as | |
254 | close as possible given the contents of the line. This goal column remains | |
255 | in effect until canceled. | |
256 | @item C-u C-x C-n | |
257 | Cancel the goal column. Henceforth, @kbd{C-n} and @kbd{C-p} once | |
258 | again try to stick to a fixed horizontal position, as usual. | |
259 | @end table | |
260 | ||
261 | @vindex track-eol | |
262 | If you set the variable @code{track-eol} to a non-@code{nil} value, | |
015a26d7 | 263 | then @kbd{C-n} and @kbd{C-p}, when starting at the end of the line, move |
6bf7aab6 DL |
264 | to the end of another line. Normally, @code{track-eol} is @code{nil}. |
265 | @xref{Variables}, for how to set variables such as @code{track-eol}. | |
266 | ||
267 | @vindex next-line-add-newlines | |
c7bda15b | 268 | @kbd{C-n} normally stops at the end of the buffer when you use it on |
1b53c26e RS |
269 | the last line of the buffer. But if you set the variable |
270 | @code{next-line-add-newlines} to a non-@code{nil} value, @kbd{C-n} on | |
271 | the last line of a buffer creates an additional line at the end and | |
272 | moves down onto it. | |
6bf7aab6 | 273 | |
177c0ea7 | 274 | @node Erasing |
6bf7aab6 DL |
275 | @section Erasing Text |
276 | ||
277 | @table @kbd | |
278 | @item @key{DEL} | |
279 | Delete the character before point (@code{delete-backward-char}). | |
280 | @item C-d | |
281 | Delete the character after point (@code{delete-char}). | |
06a97e7d RS |
282 | @item @key{DELETE} |
283 | @itemx @key{BACKSPACE} | |
284 | One of these keys, whichever is the large key above the @key{RET} or | |
285 | @key{ENTER} key, deletes the character before point, like @key{DEL}. | |
286 | If that is @key{BACKSPACE}, and your keyboard also has @key{DELETE}, | |
287 | then @key{DELETE} deletes forwards, like @kbd{C-d}. | |
6bf7aab6 DL |
288 | @item C-k |
289 | Kill to the end of the line (@code{kill-line}). | |
290 | @item M-d | |
291 | Kill forward to the end of the next word (@code{kill-word}). | |
292 | @item M-@key{DEL} | |
293 | Kill back to the beginning of the previous word | |
294 | (@code{backward-kill-word}). | |
295 | @end table | |
296 | ||
297 | @cindex killing characters and lines | |
298 | @cindex deleting characters and lines | |
299 | @cindex erasing characters and lines | |
300 | You already know about the @key{DEL} key which deletes the character | |
301 | before point (that is, before the cursor). Another key, @kbd{Control-d} | |
302 | (@kbd{C-d} for short), deletes the character after point (that is, the | |
303 | character that the cursor is on). This shifts the rest of the text on | |
304 | the line to the left. If you type @kbd{C-d} at the end of a line, it | |
305 | joins together that line and the next line. | |
306 | ||
307 | To erase a larger amount of text, use the @kbd{C-k} key, which kills a | |
308 | line at a time. If you type @kbd{C-k} at the beginning or middle of a | |
309 | line, it kills all the text up to the end of the line. If you type | |
310 | @kbd{C-k} at the end of a line, it joins that line and the next line. | |
311 | ||
312 | @xref{Killing}, for more flexible ways of killing text. | |
313 | ||
314 | @node Undo | |
315 | @section Undoing Changes | |
316 | @cindex undo | |
317 | @cindex changes, undoing | |
318 | ||
319 | You can undo all the recent changes in the buffer text, up to a | |
320 | certain point. Each buffer records changes individually, and the undo | |
321 | command always applies to the current buffer. Usually each editing | |
322 | command makes a separate entry in the undo records, but some commands | |
323 | such as @code{query-replace} make many entries, and very simple commands | |
324 | such as self-inserting characters are often grouped to make undoing less | |
325 | tedious. | |
326 | ||
327 | @table @kbd | |
328 | @item C-x u | |
329 | Undo one batch of changes---usually, one command worth (@code{undo}). | |
330 | @item C-_ | |
1b53c26e | 331 | @itemx C-/ |
6bf7aab6 DL |
332 | The same. |
333 | @item C-u C-x u | |
334 | Undo one batch of changes in the region. | |
335 | @end table | |
336 | ||
337 | @kindex C-x u | |
338 | @kindex C-_ | |
1b53c26e | 339 | @kindex C-/ |
6bf7aab6 | 340 | @findex undo |
1b53c26e RS |
341 | The command @kbd{C-x u} (or @kbd{C-_} or @kbd{C-/}) is how you undo. |
342 | The first time you give this command, it undoes the last change. | |
343 | Point moves back to where it was before the command that made the | |
344 | change. | |
6bf7aab6 DL |
345 | |
346 | Consecutive repetitions of @kbd{C-_} or @kbd{C-x u} undo earlier and | |
347 | earlier changes, back to the limit of the undo information available. | |
348 | If all recorded changes have already been undone, the undo command | |
1ba2ce68 | 349 | displays an error message and does nothing. |
6bf7aab6 | 350 | |
33e54c87 | 351 | @findex undo-only |
6bf7aab6 DL |
352 | Any command other than an undo command breaks the sequence of undo |
353 | commands. Starting from that moment, the previous undo commands become | |
354 | ordinary changes that you can undo. Thus, to redo changes you have | |
355 | undone, type @kbd{C-f} or any other command that will harmlessly break | |
33e54c87 RS |
356 | the sequence of undoing, then type more undo commands. On the other |
357 | hand, if you want to ignore previous undo commands, use @kbd{M-x | |
358 | undo-only}. This is like @code{undo}, but will not redo changes | |
359 | you have just undone. | |
6bf7aab6 DL |
360 | |
361 | @cindex selective undo | |
362 | @kindex C-u C-x u | |
363 | Ordinary undo applies to all changes made in the current buffer. You | |
1b53c26e | 364 | can also perform @dfn{selective undo}, limited to the current region |
b7fe9089 | 365 | (@pxref{Mark}). |
6bf7aab6 DL |
366 | To do this, specify the region you want, then run the @code{undo} |
367 | command with a prefix argument (the value does not matter): @kbd{C-u C-x | |
368 | u} or @kbd{C-u C-_}. This undoes the most recent change in the region. | |
369 | To undo further changes in the same region, repeat the @code{undo} | |
1b53c26e RS |
370 | command (no prefix argument is needed). In Transient Mark mode |
371 | (@pxref{Transient Mark}), any use of @code{undo} when there is an | |
372 | active region performs selective undo; you do not need a prefix | |
373 | argument. | |
6bf7aab6 DL |
374 | |
375 | If you notice that a buffer has been modified accidentally, the | |
376 | easiest way to recover is to type @kbd{C-_} repeatedly until the stars | |
377 | disappear from the front of the mode line. At this time, all the | |
378 | modifications you made have been canceled. Whenever an undo command | |
379 | makes the stars disappear from the mode line, it means that the buffer | |
380 | contents are the same as they were when the file was last read in or | |
381 | saved. | |
382 | ||
383 | If you do not remember whether you changed the buffer deliberately, | |
384 | type @kbd{C-_} once. When you see the last change you made undone, you | |
385 | will see whether it was an intentional change. If it was an accident, | |
386 | leave it undone. If it was deliberate, redo the change as described | |
387 | above. | |
388 | ||
389 | Not all buffers record undo information. Buffers whose names start with | |
390 | spaces don't; these buffers are used internally by Emacs and its extensions | |
391 | to hold text that users don't normally look at or edit. | |
392 | ||
393 | You cannot undo mere cursor motion; only changes in the buffer | |
394 | contents save undo information. However, some cursor motion commands | |
395 | set the mark, so if you use these commands from time to time, you can | |
396 | move back to the neighborhoods you have moved through by popping the | |
397 | mark ring (@pxref{Mark Ring}). | |
398 | ||
399 | @vindex undo-limit | |
400 | @vindex undo-strong-limit | |
aa3dd3b5 | 401 | @vindex undo-outer-limit |
6bf7aab6 DL |
402 | @cindex undo limit |
403 | When the undo information for a buffer becomes too large, Emacs | |
404 | discards the oldest undo information from time to time (during garbage | |
405 | collection). You can specify how much undo information to keep by | |
aa3dd3b5 RS |
406 | setting three variables: @code{undo-limit}, @code{undo-strong-limit}, |
407 | and @code{undo-outer-limit}. Their values are expressed in units of | |
408 | bytes of space. | |
6bf7aab6 DL |
409 | |
410 | The variable @code{undo-limit} sets a soft limit: Emacs keeps undo | |
aa3dd3b5 RS |
411 | data for enough commands to reach this size, and perhaps exceed it, |
412 | but does not keep data for any earlier commands beyond that. Its | |
413 | default value is 20000. The variable @code{undo-strong-limit} sets a | |
414 | stricter limit: a previous command (not the most recent one) which | |
415 | pushes the size past this amount is itself forgotten. The default | |
416 | value of @code{undo-strong-limit} is 30000. | |
417 | ||
418 | Regardless of the values of those variables, the most recent change | |
419 | is never discarded unless it gets bigger than @code{undo-outer-limit} | |
23c5319c | 420 | (normally 3,000,000). At that point, Emacs discards the undo data and |
7f9c94b0 | 421 | warns you about it. This is the only situation in which you cannot |
23c5319c LT |
422 | undo the last command. If this happens, you can increase the value of |
423 | @code{undo-outer-limit} to make it even less likely to happen in the | |
424 | future. But if you didn't expect the command to create such large | |
425 | undo data, then it is probably a bug and you should report it. | |
426 | @xref{Bugs,, Reporting Bugs}. | |
6bf7aab6 | 427 | |
1b53c26e RS |
428 | The reason the @code{undo} command has three key bindings, @kbd{C-x |
429 | u}, @kbd{C-_} and @kbd{C-/}, is that it is worthy of a | |
430 | single-character key, but @kbd{C-x u} is more straightforward for | |
431 | beginners to type. | |
6bf7aab6 DL |
432 | |
433 | @node Basic Files | |
434 | @section Files | |
435 | ||
436 | The commands described above are sufficient for creating and altering | |
437 | text in an Emacs buffer; the more advanced Emacs commands just make | |
438 | things easier. But to keep any text permanently you must put it in a | |
439 | @dfn{file}. Files are named units of text which are stored by the | |
440 | operating system for you to retrieve later by name. To look at or use | |
441 | the contents of a file in any way, including editing the file with | |
442 | Emacs, you must specify the file name. | |
443 | ||
444 | Consider a file named @file{/usr/rms/foo.c}. In Emacs, to begin editing | |
445 | this file, type | |
446 | ||
447 | @example | |
448 | C-x C-f /usr/rms/foo.c @key{RET} | |
449 | @end example | |
450 | ||
451 | @noindent | |
452 | Here the file name is given as an @dfn{argument} to the command @kbd{C-x | |
453 | C-f} (@code{find-file}). That command uses the @dfn{minibuffer} to | |
454 | read the argument, and you type @key{RET} to terminate the argument | |
455 | (@pxref{Minibuffer}).@refill | |
456 | ||
457 | Emacs obeys the command by @dfn{visiting} the file: creating a buffer, | |
458 | copying the contents of the file into the buffer, and then displaying | |
459 | the buffer for you to edit. If you alter the text, you can @dfn{save} | |
460 | the new text in the file by typing @kbd{C-x C-s} (@code{save-buffer}). | |
461 | This makes the changes permanent by copying the altered buffer contents | |
462 | back into the file @file{/usr/rms/foo.c}. Until you save, the changes | |
463 | exist only inside Emacs, and the file @file{foo.c} is unaltered. | |
464 | ||
465 | To create a file, just visit the file with @kbd{C-x C-f} as if it | |
466 | already existed. This creates an empty buffer in which you can insert | |
467 | the text you want to put in the file. The file is actually created when | |
468 | you save this buffer with @kbd{C-x C-s}. | |
469 | ||
470 | Of course, there is a lot more to learn about using files. @xref{Files}. | |
471 | ||
472 | @node Basic Help | |
473 | @section Help | |
474 | ||
475 | @cindex getting help with keys | |
476 | If you forget what a key does, you can find out with the Help | |
477 | character, which is @kbd{C-h} (or @key{F1}, which is an alias for | |
478 | @kbd{C-h}). Type @kbd{C-h k} followed by the key you want to know | |
479 | about; for example, @kbd{C-h k C-n} tells you all about what @kbd{C-n} | |
480 | does. @kbd{C-h} is a prefix key; @kbd{C-h k} is just one of its | |
481 | subcommands (the command @code{describe-key}). The other subcommands of | |
482 | @kbd{C-h} provide different kinds of help. Type @kbd{C-h} twice to get | |
483 | a description of all the help facilities. @xref{Help}.@refill | |
484 | ||
485 | @node Blank Lines | |
486 | @section Blank Lines | |
487 | ||
488 | @cindex inserting blank lines | |
489 | @cindex deleting blank lines | |
490 | Here are special commands and techniques for putting in and taking out | |
491 | blank lines. | |
492 | ||
6bf7aab6 DL |
493 | @table @kbd |
494 | @item C-o | |
495 | Insert one or more blank lines after the cursor (@code{open-line}). | |
496 | @item C-x C-o | |
497 | Delete all but one of many consecutive blank lines | |
498 | (@code{delete-blank-lines}). | |
499 | @end table | |
500 | ||
501 | @kindex C-o | |
502 | @kindex C-x C-o | |
503 | @cindex blank lines | |
504 | @findex open-line | |
505 | @findex delete-blank-lines | |
506 | When you want to insert a new line of text before an existing line, you | |
507 | can do it by typing the new line of text, followed by @key{RET}. | |
508 | However, it may be easier to see what you are doing if you first make a | |
509 | blank line and then insert the desired text into it. This is easy to do | |
510 | using the key @kbd{C-o} (@code{open-line}), which inserts a newline | |
511 | after point but leaves point in front of the newline. After @kbd{C-o}, | |
512 | type the text for the new line. @kbd{C-o F O O} has the same effect as | |
513 | @w{@kbd{F O O @key{RET}}}, except for the final location of point. | |
514 | ||
515 | You can make several blank lines by typing @kbd{C-o} several times, or | |
516 | by giving it a numeric argument to tell it how many blank lines to make. | |
c7bda15b | 517 | @xref{Arguments}, for how. If you have a fill prefix, the @kbd{C-o} |
6bf7aab6 DL |
518 | command inserts the fill prefix on the new line, when you use it at the |
519 | beginning of a line. @xref{Fill Prefix}. | |
520 | ||
521 | The easy way to get rid of extra blank lines is with the command | |
522 | @kbd{C-x C-o} (@code{delete-blank-lines}). @kbd{C-x C-o} in a run of | |
523 | several blank lines deletes all but one of them. @kbd{C-x C-o} on a | |
524 | solitary blank line deletes that blank line. When point is on a | |
525 | nonblank line, @kbd{C-x C-o} deletes any blank lines following that | |
526 | nonblank line. | |
527 | ||
528 | @node Continuation Lines | |
529 | @section Continuation Lines | |
530 | ||
531 | @cindex continuation line | |
532 | @cindex wrapping | |
533 | @cindex line wrapping | |
e56823d9 | 534 | @cindex fringes, and continuation lines |
6bf7aab6 | 535 | If you add too many characters to one line without breaking it with |
093b0ab5 RS |
536 | @key{RET}, the line grows to occupy two (or more) lines on the screen. |
537 | On graphical displays, Emacs indicates line wrapping with small bent | |
538 | arrows in the fringes to the left and right of the window. On | |
539 | text-only terminals, Emacs displays a @samp{\} character at the right | |
540 | margin of a screen line if it is not the last in its text line. This | |
541 | @samp{\} character says that the following screen line is not really a | |
542 | distinct line in the text, just a @dfn{continuation} of a line too | |
543 | long to fit the screen. Continuation is also called @dfn{line | |
544 | wrapping}. | |
545 | ||
546 | When line wrapping occurs before a character that is wider than one | |
547 | column, some columns at the end of the previous screen line may be | |
548 | ``empty.'' In this case, Emacs displays additional @samp{\} | |
549 | characters in the ``empty'' columns, just before the @samp{\} | |
550 | character that indicates continuation. | |
6bf7aab6 DL |
551 | |
552 | Sometimes it is nice to have Emacs insert newlines automatically when | |
553 | a line gets too long. Continuation on the screen does not do that. Use | |
554 | Auto Fill mode (@pxref{Filling}) if that's what you want. | |
555 | ||
6bf7aab6 | 556 | @cindex truncation |
e56823d9 | 557 | @cindex line truncation, and fringes |
6bf7aab6 | 558 | As an alternative to continuation, Emacs can display long lines by |
457b792c | 559 | @dfn{truncation}. This means that all the characters that do not fit |
ab527690 RS |
560 | in the width of the screen or window do not appear at all. @samp{$} |
561 | in the last column or a small straight arrow in the fringe to the | |
562 | right of the window indicates a truncated line. | |
563 | ||
564 | @xref{Display Custom}, for more information about line truncation, | |
565 | and other variables that affect how text is displayed. | |
6bf7aab6 DL |
566 | |
567 | @node Position Info | |
568 | @section Cursor Position Information | |
569 | ||
570 | Here are commands to get information about the size and position of | |
571 | parts of the buffer, and to count lines. | |
572 | ||
573 | @table @kbd | |
574 | @item M-x what-page | |
093b0ab5 | 575 | Display the page number of point, and the line number within the page. |
6bf7aab6 | 576 | @item M-x what-line |
093b0ab5 | 577 | Display the line number of point in the buffer. |
6bf7aab6 | 578 | @item M-x line-number-mode |
67675c0f DL |
579 | @itemx M-x column-number-mode |
580 | Toggle automatic display of current line number or column number. | |
581 | @xref{Optional Mode Line}. | |
6bf7aab6 | 582 | @item M-= |
093b0ab5 | 583 | Display the number of lines in the current region (@code{count-lines-region}). |
6bf7aab6 DL |
584 | @xref{Mark}, for information about the region. |
585 | @item C-x = | |
093b0ab5 | 586 | Display the character code of character after point, character position of |
6bf7aab6 | 587 | point, and column of point (@code{what-cursor-position}). |
67675c0f | 588 | @item M-x hl-line-mode |
83440f52 EZ |
589 | Enable or disable highlighting of the current line. @xref{Cursor |
590 | Display}. | |
ffa11cf3 LK |
591 | @item M-x size-indication-mode |
592 | Toggle automatic display of the size of the buffer. | |
593 | @xref{Optional Mode Line}. | |
6bf7aab6 DL |
594 | @end table |
595 | ||
596 | @findex what-page | |
597 | @findex what-line | |
598 | @cindex line number commands | |
599 | @cindex location of point | |
600 | @cindex cursor location | |
601 | @cindex point location | |
706f4350 LT |
602 | @kbd{M-x what-line} computes the current line number and displays it |
603 | in the echo area. You can also see the current line number in the | |
604 | mode line; see @ref{Mode Line}. If you narrow the buffer, then the | |
605 | line number in the mode line is relative to the accessible portion | |
606 | (@pxref{Narrowing}). By contrast, @code{what-line} shows both the | |
607 | line number relative to the narrowed region and the line number | |
608 | relative to the whole buffer. | |
6bf7aab6 | 609 | |
9acb8eec | 610 | @kbd{M-x what-page} counts pages from the beginning of the file, and |
1ba2ce68 RS |
611 | counts lines within the page, showing both numbers in the echo area. |
612 | @xref{Pages}. | |
6bf7aab6 DL |
613 | |
614 | @kindex M-= | |
615 | @findex count-lines-region | |
616 | While on this subject, we might as well mention @kbd{M-=} (@code{count-lines-region}), | |
1ba2ce68 | 617 | which displays the number of lines in the region (@pxref{Mark}). |
6bf7aab6 DL |
618 | @xref{Pages}, for the command @kbd{C-x l} which counts the lines in the |
619 | current page. | |
620 | ||
621 | @kindex C-x = | |
622 | @findex what-cursor-position | |
6cf1bebc RS |
623 | The command @kbd{C-x =} (@code{what-cursor-position}) shows what |
624 | column the cursor is in, and other miscellaneous information about | |
625 | point and the character after it. It displays a line in the echo area | |
626 | that looks like this: | |
6bf7aab6 DL |
627 | |
628 | @smallexample | |
177c0ea7 | 629 | Char: c (0143, 99, 0x63) point=21044 of 26883(78%) column 53 |
6bf7aab6 DL |
630 | @end smallexample |
631 | ||
632 | @noindent | |
633 | (In fact, this is the output produced when point is before the | |
634 | @samp{column} in the example.) | |
635 | ||
636 | The four values after @samp{Char:} describe the character that follows | |
637 | point, first by showing it and then by giving its character code in | |
76dd3692 | 638 | octal, decimal and hex. For a non-@acronym{ASCII} multibyte character, these are |
6bf7aab6 DL |
639 | followed by @samp{ext} and the character's representation, in hex, in |
640 | the buffer's coding system, if that coding system encodes the character | |
641 | safely and with a single byte (@pxref{Coding Systems}). If the | |
642 | character's encoding is longer than one byte, Emacs shows @samp{ext ...}. | |
643 | ||
644 | @samp{point=} is followed by the position of point expressed as a character | |
645 | count. The front of the buffer counts as position 1, one character later | |
646 | as 2, and so on. The next, larger, number is the total number of characters | |
647 | in the buffer. Afterward in parentheses comes the position expressed as a | |
648 | percentage of the total size. | |
649 | ||
650 | @samp{column} is followed by the horizontal position of point, in | |
651 | columns from the left edge of the window. | |
652 | ||
653 | If the buffer has been narrowed, making some of the text at the | |
1ba2ce68 | 654 | beginning and the end temporarily inaccessible, @kbd{C-x =} displays |
6bf7aab6 DL |
655 | additional text describing the currently accessible range. For example, it |
656 | might display this: | |
657 | ||
658 | @smallexample | |
177c0ea7 | 659 | Char: C (0103, 67, 0x43) point=252 of 889(28%) <231 - 599> column 0 |
6bf7aab6 DL |
660 | @end smallexample |
661 | ||
662 | @noindent | |
663 | where the two extra numbers give the smallest and largest character | |
664 | position that point is allowed to assume. The characters between those | |
665 | two positions are the accessible ones. @xref{Narrowing}. | |
666 | ||
667 | If point is at the end of the buffer (or the end of the accessible | |
668 | part), the @w{@kbd{C-x =}} output does not describe a character after | |
669 | point. The output might look like this: | |
670 | ||
671 | @smallexample | |
01005464 | 672 | point=26957 of 26956(100%) column 0 |
6bf7aab6 DL |
673 | @end smallexample |
674 | ||
01005464 | 675 | @cindex character set of character at point |
7923e3c2 | 676 | @cindex font of character at point |
01005464 | 677 | @cindex text properties at point |
c7bda15b | 678 | @w{@kbd{C-u C-x =}} displays the following additional information about a |
27a132c3 KH |
679 | character. |
680 | ||
681 | @itemize @bullet | |
682 | @item | |
42a99593 | 683 | The character set name, and the codes that identify the character |
27a132c3 KH |
684 | within that character set; @acronym{ASCII} characters are identified |
685 | as belonging to the @code{ascii} character set. | |
686 | ||
687 | @item | |
688 | The character's syntax and categories. | |
689 | ||
690 | @item | |
42a99593 RS |
691 | The character's encodings, both internally in the buffer, and externally |
692 | if you were to save the file. | |
27a132c3 KH |
693 | |
694 | @item | |
42a99593 RS |
695 | What to type to input the character in the current input method |
696 | (if it supports the character). | |
27a132c3 KH |
697 | |
698 | @item | |
699 | If you are running Emacs on a window system, the font name and glyph | |
700 | code for the character. If you are running Emacs on a terminal, the | |
701 | code(s) sent to the terminal. | |
702 | ||
703 | @item | |
704 | The character's text properties (@pxref{Text Properties,,, | |
6cf1bebc RS |
705 | elisp, the Emacs Lisp Reference Manual}), and any overlays containing it |
706 | (@pxref{Overlays,,, elisp, the same manual}). | |
27a132c3 KH |
707 | @end itemize |
708 | ||
6480c8b4 | 709 | Here's an example showing the Latin-1 character A with grave accent, |
27a132c3 | 710 | in a buffer whose coding system is @code{iso-latin-1}, whose |
6480c8b4 | 711 | terminal coding system is @code{iso-latin-1} (so the terminal actually |
01005464 EZ |
712 | displays the character as @samp{@`A}), and which has font-lock-mode |
713 | (@pxref{Font Lock}) enabled: | |
6bf7aab6 | 714 | |
9acb8eec | 715 | @smallexample |
27a132c3 KH |
716 | character: @`A (04300, 2240, 0x8c0, U+00C0) |
717 | charset: latin-iso8859-1 | |
718 | (Right-Hand Part of Latin Alphabet 1@dots{} | |
719 | code point: 64 | |
720 | syntax: w which means: word | |
721 | category: l:Latin | |
722 | to input: type "`A" | |
723 | buffer code: 0x81 0xC0 | |
724 | file code: ESC 2C 41 40 (encoded by coding system iso-2022-7bit) | |
725 | display: terminal code 0xC0 | |
726 | ||
727 | There are text properties here: | |
728 | fontified t | |
9acb8eec | 729 | @end smallexample |
6bf7aab6 DL |
730 | |
731 | @node Arguments | |
732 | @section Numeric Arguments | |
733 | @cindex numeric arguments | |
734 | @cindex prefix arguments | |
4946337d | 735 | @cindex arguments to commands |
6bf7aab6 DL |
736 | |
737 | In mathematics and computer usage, the word @dfn{argument} means | |
738 | ``data provided to a function or operation.'' You can give any Emacs | |
739 | command a @dfn{numeric argument} (also called a @dfn{prefix argument}). | |
740 | Some commands interpret the argument as a repetition count. For | |
741 | example, @kbd{C-f} with an argument of ten moves forward ten characters | |
742 | instead of one. With these commands, no argument is equivalent to an | |
743 | argument of one. Negative arguments tell most such commands to move or | |
744 | act in the opposite direction. | |
745 | ||
746 | @kindex M-1 | |
747 | @kindex M-@t{-} | |
748 | @findex digit-argument | |
749 | @findex negative-argument | |
1b53c26e RS |
750 | If your terminal keyboard has a @key{META} key (labeled @key{ALT} on |
751 | PC keyboards), the easiest way to specify a numeric argument is to | |
752 | type digits and/or a minus sign while holding down the @key{META} key. | |
753 | For example, | |
a1f6ea55 | 754 | |
6bf7aab6 DL |
755 | @example |
756 | M-5 C-n | |
757 | @end example | |
a1f6ea55 | 758 | |
6bf7aab6 DL |
759 | @noindent |
760 | would move down five lines. The characters @kbd{Meta-1}, @kbd{Meta-2}, | |
761 | and so on, as well as @kbd{Meta--}, do this because they are keys bound | |
762 | to commands (@code{digit-argument} and @code{negative-argument}) that | |
a1f6ea55 EZ |
763 | are defined to contribute to an argument for the next command. |
764 | @kbd{Meta--} without digits normally means @minus{}1. Digits and | |
765 | @kbd{-} modified with Control, or Control and Meta, also specify numeric | |
766 | arguments. | |
6bf7aab6 DL |
767 | |
768 | @kindex C-u | |
769 | @findex universal-argument | |
770 | Another way of specifying an argument is to use the @kbd{C-u} | |
771 | (@code{universal-argument}) command followed by the digits of the | |
772 | argument. With @kbd{C-u}, you can type the argument digits without | |
773 | holding down modifier keys; @kbd{C-u} works on all terminals. To type a | |
774 | negative argument, type a minus sign after @kbd{C-u}. Just a minus sign | |
775 | without digits normally means @minus{}1. | |
776 | ||
777 | @kbd{C-u} followed by a character which is neither a digit nor a minus | |
778 | sign has the special meaning of ``multiply by four.'' It multiplies the | |
779 | argument for the next command by four. @kbd{C-u} twice multiplies it by | |
780 | sixteen. Thus, @kbd{C-u C-u C-f} moves forward sixteen characters. This | |
2792c60a | 781 | is a good way to move forward ``fast,'' since it moves about 1/5 of a line |
6bf7aab6 DL |
782 | in the usual size screen. Other useful combinations are @kbd{C-u C-n}, |
783 | @kbd{C-u C-u C-n} (move down a good fraction of a screen), @kbd{C-u C-u | |
784 | C-o} (make ``a lot'' of blank lines), and @kbd{C-u C-k} (kill four | |
785 | lines).@refill | |
786 | ||
787 | Some commands care only about whether there is an argument, and not about | |
788 | its value. For example, the command @kbd{M-q} (@code{fill-paragraph}) with | |
789 | no argument fills text; with an argument, it justifies the text as well. | |
790 | (@xref{Filling}, for more information on @kbd{M-q}.) Plain @kbd{C-u} is a | |
791 | handy way of providing an argument for such commands. | |
792 | ||
793 | Some commands use the value of the argument as a repeat count, but do | |
794 | something peculiar when there is no argument. For example, the command | |
795 | @kbd{C-k} (@code{kill-line}) with argument @var{n} kills @var{n} lines, | |
796 | including their terminating newlines. But @kbd{C-k} with no argument is | |
797 | special: it kills the text up to the next newline, or, if point is right at | |
798 | the end of the line, it kills the newline itself. Thus, two @kbd{C-k} | |
799 | commands with no arguments can kill a nonblank line, just like @kbd{C-k} | |
800 | with an argument of one. (@xref{Killing}, for more information on | |
801 | @kbd{C-k}.)@refill | |
802 | ||
803 | A few commands treat a plain @kbd{C-u} differently from an ordinary | |
804 | argument. A few others may treat an argument of just a minus sign | |
805 | differently from an argument of @minus{}1. These unusual cases are | |
1b53c26e RS |
806 | described when they come up; they are always for reasons of |
807 | convenience of use of the individual command, and they are documented | |
808 | in the command's documentation string. | |
6bf7aab6 DL |
809 | |
810 | You can use a numeric argument to insert multiple copies of a | |
811 | character. This is straightforward unless the character is a digit; for | |
812 | example, @kbd{C-u 6 4 a} inserts 64 copies of the character @samp{a}. | |
813 | But this does not work for inserting digits; @kbd{C-u 6 4 1} specifies | |
814 | an argument of 641, rather than inserting anything. To separate the | |
815 | digit to insert from the argument, type another @kbd{C-u}; for example, | |
816 | @kbd{C-u 6 4 C-u 1} does insert 64 copies of the character @samp{1}. | |
817 | ||
818 | We use the term ``prefix argument'' as well as ``numeric argument'' to | |
819 | emphasize that you type the argument before the command, and to | |
820 | distinguish these arguments from minibuffer arguments that come after | |
821 | the command. | |
822 | ||
823 | @node Repeating | |
824 | @section Repeating a Command | |
825 | @cindex repeating a command | |
826 | ||
9b3ae7e4 RS |
827 | Many simple commands, such as those invoked with a single key or |
828 | with @kbd{M-x @var{command-name} @key{RET}}, can be repeated by | |
829 | invoking them with a numeric argument that serves as a repeat count | |
830 | (@pxref{Arguments}). However, if the command you want to repeat | |
831 | prompts for some input, or uses a numeric argument in another way, | |
832 | repetition using a numeric argument might be problematical. | |
68b7eaa9 | 833 | |
6bf7aab6 DL |
834 | @kindex C-x z |
835 | @findex repeat | |
836 | The command @kbd{C-x z} (@code{repeat}) provides another way to repeat | |
837 | an Emacs command many times. This command repeats the previous Emacs | |
838 | command, whatever that was. Repeating a command uses the same arguments | |
839 | that were used before; it does not read new arguments each time. | |
840 | ||
841 | To repeat the command more than once, type additional @kbd{z}'s: each | |
842 | @kbd{z} repeats the command one more time. Repetition ends when you | |
843 | type a character other than @kbd{z}, or press a mouse button. | |
844 | ||
845 | For example, suppose you type @kbd{C-u 2 0 C-d} to delete 20 | |
846 | characters. You can repeat that command (including its argument) three | |
847 | additional times, to delete a total of 80 characters, by typing @kbd{C-x | |
848 | z z z}. The first @kbd{C-x z} repeats the command once, and each | |
849 | subsequent @kbd{z} repeats it once again. | |
850 | ||
ab5796a9 MB |
851 | @ignore |
852 | arch-tag: cda8952a-c439-41c1-aecf-4bc0d6482956 | |
853 | @end ignore |