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6bf7aab6 | 1 | @c This is part of the Emacs manual. |
b65d8176 | 2 | @c Copyright (C) 1985, 1986, 1987, 1993, 1994, 1995, 1997, 2001, 2002, |
3f548a7c | 3 | @c 2003, 2004, 2005, 2006, 2007, 2008 Free Software Foundation, Inc. |
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4 | @c See file emacs.texi for copying conditions. |
5 | @node Mark, Killing, Help, Top | |
6 | @chapter The Mark and the Region | |
7 | @cindex mark | |
8 | @cindex setting a mark | |
9 | @cindex region | |
10 | ||
11 | Many Emacs commands operate on an arbitrary contiguous part of the | |
12 | current buffer. To specify the text for such a command to operate on, | |
13 | you set @dfn{the mark} at one end of it, and move point to the other | |
14 | end. The text between point and the mark is called @dfn{the region}. | |
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16 | If the mark is active, the region always extends between point and |
17 | the mark, no matter which one comes earlier in the text; each time you | |
18 | move point, the region changes. Whenever the mark is active, Emacs | |
19 | highlights the region. You can customize the appearance of this | |
20 | highlighting by changing the @code{region} face (@pxref{Face | |
21 | Customization}). | |
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22 | |
23 | The region persists only until you use it. The mark is | |
24 | automatically @dfn{deactivated} after certain non-motion commands, | |
25 | including any command that changes the text in the buffer. You can | |
26 | also explicitly deactivate the mark at any time, by typing @kbd{C-g} | |
27 | (@pxref{Quitting}). | |
28 | ||
29 | @vindex highlight-nonselected-windows | |
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30 | Setting the mark in one buffer has no effect on the marks in other |
31 | buffers. When you return to a buffer with an active mark, the mark is | |
32 | at the same place as before. When multiple windows show the same | |
33 | buffer, they can have different values of point, and thus different | |
34 | regions, but they all share one common mark position. @xref{Windows}. | |
35 | Ordinarily, only the selected window highlights its region; however, | |
36 | if the variable @code{highlight-nonselected-windows} is | |
37 | non-@code{nil}, each window highlights its own region. | |
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38 | |
39 | @menu | |
40 | * Setting Mark:: Commands to set the mark. | |
6bf7aab6 | 41 | * Marking Objects:: Commands to put region around textual units. |
a8a31aae | 42 | * Using Region:: Summary of ways to operate on contents of the region. |
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43 | * Mark Ring:: Previous mark positions saved so you can go back there. |
44 | * Global Mark Ring:: Previous mark positions in various buffers. | |
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45 | * Shift selection:: Using shifted cursor motion keys. |
46 | * Persistent Mark:: Keeping the mark active all the time. | |
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47 | @end menu |
48 | ||
49 | @node Setting Mark | |
50 | @section Setting the Mark | |
51 | ||
52 | Here are some commands for setting the mark: | |
53 | ||
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54 | @table @kbd |
55 | @item C-@key{SPC} | |
0665a8b0 | 56 | Set the mark at point (@code{set-mark-command}). |
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57 | @item C-@@ |
58 | The same. | |
59 | @item C-x C-x | |
0665a8b0 | 60 | Set the mark at point, and move point where the mark was |
a8a31aae | 61 | (@code{exchange-point-and-mark}). |
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62 | @item Drag-Mouse-1 |
63 | Set point and the mark around the text you drag across. | |
64 | @item Mouse-3 | |
0665a8b0 | 65 | Set the mark at point, then move point to where you click |
6bf7aab6 | 66 | (@code{mouse-save-then-kill}). |
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67 | @item @samp{Shifted motion keys} |
68 | Set the mark at point if the mark is inactive, then move point. | |
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69 | @end table |
70 | ||
6bf7aab6 | 71 | @kindex C-SPC |
0665a8b0 | 72 | @kindex C-@@ |
6bf7aab6 | 73 | @findex set-mark-command |
a8a31aae | 74 | The most common way to set the mark is with @kbd{C-@key{SPC}} |
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75 | (@code{set-mark-command}), which sets the mark where point |
76 | is@footnote{There is no @kbd{C-@key{SPC}} character in | |
77 | @acronym{ASCII}; usually, typing @kbd{C-@key{SPC}} on a text terminal | |
78 | gives the character @kbd{C-@@}. This key is also bound to | |
79 | @code{set-mark-command}, so unless you are unlucky enough to have an | |
80 | text terminal that behaves differently, you might as well think of | |
81 | @kbd{C-@@} as @kbd{C-@key{SPC}}.}. You can then move point away, | |
82 | leaving the mark behind. | |
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83 | |
84 | For example, suppose you wish to convert part of the buffer to upper | |
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85 | case. To accomplish this, go to the beginning of the desired text, |
86 | type @kbd{C-@key{SPC}}, and move point until the desired portion of | |
87 | text is highlighted. Now type @kbd{C-x C-u} (@code{upcase-region}). | |
88 | This converts the text in the region to upper case, and then | |
89 | deactivates the mark. | |
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90 | |
91 | @kindex C-x C-x | |
92 | @findex exchange-point-and-mark | |
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93 | The command @kbd{C-x C-x} (@code{exchange-point-and-mark}) exchanges |
94 | the positions of point and the mark, keeping the region unchanged. If | |
95 | no mark is active, Emacs first reactivates the mark wherever it was | |
96 | last set. @kbd{C-x C-x} is useful when you are satisfied with the | |
97 | position of point but want to move the other end of the region (where | |
98 | the mark is). Using @kbd{C-x C-x} a second time, if necessary, puts | |
99 | the mark at the new position with point back at its original position. | |
100 | ||
101 | You can also set the mark with the mouse (@pxref{Mouse Commands}). | |
102 | If you press the left mouse button (@kbd{down-mouse-1}) and drag the | |
103 | mouse across a range of text while holding down this button, this sets | |
104 | the mark where you first pressed the mouse button and puts point where | |
105 | you release it. Alternatively, clicking the right mouse button | |
106 | (@kbd{mouse-3}) sets the mark at point and then moves point to where | |
107 | you clicked. Using the mouse to mark a region also copies the region | |
108 | into the kill ring (@pxref{Kill Ring}). | |
109 | ||
110 | @cindex shift-selection | |
111 | Finally, you can set the mark by holding down the shift key while | |
112 | typing certain cursor motion commands (such as @kbd{S-@key{right}}, | |
113 | @kbd{S-C-f}, @kbd{S-C-n}, etc.) This is referred to as | |
114 | @dfn{shift-selection}. This sets the mark at point before moving | |
115 | point, but only if there is no active mark set via shift-selection. | |
116 | The mark set by mouse commands and by shift-selection behaves slightly | |
117 | differently from the usual mark: any subsequent unshifted cursor | |
118 | motion command deactivates it automatically. For details, @xref{Shift | |
119 | selection}. | |
6bf7aab6 | 120 | |
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121 | Whenever the mark is active, you can deactivate it by typing |
122 | @kbd{C-g} (@pxref{Quitting}). The mark is also automatically | |
123 | deactivated after certain non-motion commands. | |
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124 | |
125 | @node Marking Objects | |
126 | @section Commands to Mark Textual Objects | |
127 | ||
128 | @cindex marking sections of text | |
129 | Here are the commands for placing point and the mark around a textual | |
a8a31aae | 130 | object such as a word, list, paragraph or page: |
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131 | |
132 | @table @kbd | |
133 | @item M-@@ | |
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134 | Set mark after end of next word (@code{mark-word}). This does not |
135 | move point. | |
6bf7aab6 | 136 | @item C-M-@@ |
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137 | Set mark after end of following balanced expression |
138 | (@code{mark-sexp}). This does not move point. | |
6bf7aab6 | 139 | @item M-h |
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140 | Move point to the beginning of the current paragraph, and set mark at |
141 | the end (@code{mark-paragraph}). | |
6bf7aab6 | 142 | @item C-M-h |
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143 | Move point to the beginning of the current defun, and set mark at the |
144 | end (@code{mark-defun}). | |
6bf7aab6 | 145 | @item C-x C-p |
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146 | Move point to the beginning of the current page, and set mark at the |
147 | end (@code{mark-page}). | |
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148 | @item C-x h |
149 | Move point to the beginning of the buffer, and set mark at the end | |
150 | (@code{mark-whole-buffer}). | |
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151 | @end table |
152 | ||
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153 | @findex mark-word |
154 | @findex mark-sexp | |
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155 | @kbd{M-@@} (@code{mark-word}) puts the mark at the end of the next |
156 | word, while @kbd{C-M-@@} (@code{mark-sexp}) puts it at the end of the | |
157 | next balanced expression (@pxref{Expressions}). These commands handle | |
a8a31aae | 158 | arguments just like @kbd{M-f} and @kbd{C-M-f}. |
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159 | |
160 | @kindex C-x h | |
161 | @findex mark-whole-buffer | |
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162 | The other commands in the above list set both point and mark, so as |
163 | to delimit an object in the buffer. @kbd{M-h} (@code{mark-paragraph}) | |
164 | moves point to the beginning of the paragraph that surrounds or | |
165 | follows point, and sets the mark at the end of that paragraph | |
166 | (@pxref{Paragraphs}). As a special exception, repeated invocations of | |
167 | @kbd{M-h} extend the region to subsequent paragraphs. This is | |
168 | convenient for indenting, case-converting, or killing entire | |
169 | paragraphs. | |
170 | ||
171 | The @kbd{M-h} command accepts prefix arguments. If the argument's | |
172 | value is positive, @kbd{M-h} marks that many paragraphs starting with | |
173 | the one surrounding point; therefore, @kbd{C-u M-h} is equivalent to | |
174 | @kbd{M-h M-h M-h M-h}. If the prefix argument is @minus{}@var{n}, | |
175 | @kbd{M-h} marks @var{n} paragraphs running back from the one | |
176 | surrounding point; in this case, point moves forward to the end of | |
177 | that paragraph, and the mark goes at the start of the region. | |
178 | ||
179 | Similarly, @kbd{C-M-h} (@code{mark-defun}) sets mark and point | |
180 | around major top-level definitions (@pxref{Moving by Defuns}), and | |
181 | @kbd{C-x C-p} (@code{mark-page}) does the same for pages | |
182 | (@pxref{Pages}). These treat repeated invokations and prefix | |
183 | arguments similarly to @code{mark-paragraph}. | |
a8a31aae | 184 | |
6bf7aab6 | 185 | Finally, @kbd{C-x h} (@code{mark-whole-buffer}) sets up the entire |
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186 | buffer as the region, by putting point at the beginning and the mark |
187 | at the end. (In some programs this is called ``select all.'') | |
6bf7aab6 | 188 | |
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189 | @node Using Region |
190 | @section Operating on the Region | |
191 | ||
192 | @cindex operations on a marked region | |
193 | Once you have a region, here are some of the ways you can operate on | |
194 | it: | |
195 | ||
196 | @itemize @bullet | |
197 | @item | |
198 | Kill it with @kbd{C-w} (@pxref{Killing}). | |
199 | @item | |
200 | Copy it to the kill ring with @kbd{M-w} (@pxref{Yanking}). | |
201 | @item | |
202 | Convert case with @kbd{C-x C-l} or @kbd{C-x C-u} (@pxref{Case}). | |
203 | @item | |
204 | Undo changes within it using @kbd{C-u C-/} (@pxref{Undo}). | |
205 | @item | |
206 | Replace text within it using @kbd{M-%} (@pxref{Query Replace}). | |
207 | @item | |
208 | Indent it with @kbd{C-x @key{TAB}} or @kbd{C-M-\} (@pxref{Indentation}). | |
209 | @item | |
210 | Fill it as text with @kbd{M-x fill-region} (@pxref{Filling}). | |
211 | @item | |
212 | Print hardcopy with @kbd{M-x print-region} (@pxref{Printing}). | |
213 | @item | |
214 | Evaluate it as Lisp code with @kbd{M-x eval-region} (@pxref{Lisp Eval}). | |
215 | @item | |
216 | Save it in a register with @kbd{C-x r s} (@pxref{Registers}). | |
217 | @item | |
218 | Save it in a buffer or a file (@pxref{Accumulating Text}). | |
219 | @end itemize | |
220 | ||
221 | Most commands that operate on the text in the region have the word | |
222 | @code{region} in their names. | |
223 | ||
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224 | If Delete Selection mode is enabled, some commands delete the region |
225 | when used while the mark is active. @xref{Mouse Commands}. | |
226 | ||
227 | @node Mark Ring | |
228 | @section The Mark Ring | |
229 | ||
230 | @cindex mark ring | |
231 | Aside from delimiting the region, the mark is also useful for | |
232 | remembering spots that you may want to go back to. Each buffer | |
233 | remembers 16 previous locations of the mark, in the @dfn{mark ring}. | |
234 | Commands that set the mark also push the old mark onto this ring. | |
235 | ||
236 | @table @kbd | |
237 | @item C-@key{SPC} C-@key{SPC} | |
238 | Set the mark, pushing it onto the mark ring, without activating it. | |
239 | @item C-u C-@key{SPC} | |
240 | Move point to where the mark was, and restore the mark from the ring | |
241 | of former marks. | |
242 | @end table | |
243 | ||
244 | @kindex C-SPC C-SPC | |
245 | The command C-@key{SPC} C-@key{SPC} is handy when you want to use | |
246 | the mark to remember a position to which you may wish to return. It | |
247 | pushes the current point onto the mark ring, without activating the | |
248 | mark (which would cause Emacs to highlight the region). This is | |
249 | actually two consecutive invocations of @kbd{C-@key{SPC}} | |
250 | (@code{set-mark-command}); the first @kbd{C-@key{SPC}} sets the mark, | |
251 | and the second @kbd{C-@key{SPC}} deactivates it. (When Transient Mark | |
252 | mode is off, C-@key{SPC} C-@key{SPC} instead activates Transient Mark | |
253 | mode temporarily. @xref{Persistent Mark}.) | |
254 | ||
255 | @kindex C-u C-SPC | |
256 | To return to a marked position, use @code{set-mark-command} with a | |
257 | prefix argument: @kbd{C-u C-@key{SPC}}. This moves point to where the | |
258 | mark was, and deactivates the mark if it was active. Each subsequent | |
259 | @kbd{C-u C-@key{SPC}} jumps to a prior position stored in the mark | |
260 | ring. The positions you move through in this way are not lost; they | |
261 | go to the end of the ring. | |
262 | ||
263 | @vindex set-mark-command-repeat-pop | |
264 | If you set @code{set-mark-command-repeat-pop} to non-@code{nil}, | |
265 | then immediately after you type @kbd{C-u C-@key{SPC}}, you can type | |
266 | @kbd{C-@key{SPC}} instead of @kbd{C-u C-@key{SPC}} to cycle through | |
267 | the mark ring. By default, @code{set-mark-command-repeat-pop} is | |
268 | @code{nil}. | |
269 | ||
270 | Each buffer has its own mark ring. All editing commands use the | |
271 | current buffer's mark ring. In particular, @kbd{C-u C-@key{SPC}} | |
272 | always stays in the same buffer. | |
273 | ||
274 | @vindex mark-ring-max | |
275 | The variable @code{mark-ring-max} specifies the maximum number of | |
276 | entries to keep in the mark ring. If that many entries exist and | |
277 | another one is pushed, the earliest one in the list is discarded. Repeating | |
278 | @kbd{C-u C-@key{SPC}} cycles through the positions currently in the | |
279 | ring. | |
280 | ||
281 | @vindex mark-even-if-inactive | |
282 | If the variable @code{mark-even-if-inactive} is @code{nil}, commands | |
283 | can only use the mark and the region when it is active. This variable | |
284 | is non-@code{nil} by default. | |
285 | ||
286 | If you want to move back to the same place over and over, the mark | |
287 | ring may not be convenient enough. If so, you can record the position | |
288 | in a register for later retrieval (@pxref{RegPos,, Saving Positions in | |
289 | Registers}). | |
290 | ||
291 | @node Global Mark Ring | |
292 | @section The Global Mark Ring | |
293 | @cindex global mark ring | |
294 | ||
295 | In addition to the ordinary mark ring that belongs to each buffer, | |
296 | Emacs has a single @dfn{global mark ring}. Each time you set a mark, | |
297 | in any buffer, this is recorded in the global mark ring in addition to | |
298 | the current buffer's own mark ring. | |
299 | ||
300 | @kindex C-x C-@key{SPC} | |
301 | @findex pop-global-mark | |
302 | The command @kbd{C-x C-@key{SPC}} (@code{pop-global-mark}) jumps to | |
303 | the buffer and position of the latest entry in the global ring. It also | |
304 | rotates the ring, so that successive uses of @kbd{C-x C-@key{SPC}} take | |
305 | you to earlier buffers and mark positions. | |
306 | ||
307 | @node Shift selection | |
308 | @section Shift selection | |
309 | @cindex shift-selection | |
310 | ||
311 | If you hold down the shift key while typing a cursor motion command, | |
312 | this sets the mark before moving point, so that the region extends | |
313 | from the original position of point to its new position. This | |
314 | feature, newly introduced in Emacs 23, is referred to as | |
315 | @dfn{shift-selection}. It is similar to the way text is selected in | |
316 | other editors. | |
317 | ||
318 | The mark set via shift-selection behaves a little differently from | |
319 | what we have described above. Firstly, in addition to the usual ways | |
320 | of deactivating the mark (such as changing the buffer text or typing | |
321 | @kbd{C-g}), the mark is deactivated by any @emph{unshifted} cursor | |
322 | motion command. Secondly, any subsequent @emph{shifted} cursor motion | |
323 | command avoids setting the mark anew. Therefore, a series of shifted | |
324 | cursor motion commands will continuously extend the region. | |
325 | ||
326 | Shift-selection only works if the shifted cursor motion key is not | |
327 | already bound to a separate command (@pxref{Customization}). For | |
328 | example, if you bind @kbd{S-C-f} to another command, typing | |
329 | @kbd{S-C-f} runs that command instead of performing a shift-selected | |
330 | version of @kbd{C-f} (@code{forward-char}). | |
331 | ||
332 | A mark set via mouse commands behaves the same as a mark set via | |
333 | shift-selection (@pxref{Setting Mark}). For example, if you specify a | |
334 | region by dragging the mouse, you can continue to extend the region | |
335 | using shifted cursor motion commands. In either case, any unshifted | |
336 | cursor motion command deactivates the mark. | |
337 | ||
338 | To turn off shift-selection, set @code{shift-select-mode} to | |
339 | @code{nil}. Doing this does not disable setting the mark via mouse | |
340 | commands. | |
341 | ||
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342 | @node Persistent Mark |
343 | @section Persistent Marks | |
344 | @cindex mode, Transient Mark | |
345 | @cindex Transient Mark mode | |
346 | @cindex highlighting region | |
347 | @cindex region highlighting | |
348 | @cindex Zmacs mode | |
349 | ||
0665a8b0 | 350 | By default, the region is highlighted whenever it exists, and |
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351 | disappears once you use it or explicitly deactivate the mark. This |
352 | behavior is called Transient Mark mode@footnote{It is also sometimes | |
353 | called @dfn{Zmacs mode}, because the Zmacs editor on the MIT Lisp | |
354 | Machine handled the mark in a similar way.}. | |
355 | ||
356 | @findex transient-mark-mode | |
357 | Turning off Transient Mark mode switches Emacs to an alternative | |
358 | mode of operation, which was the default prior to Emacs 23. When | |
359 | Transient Mark mode is off, the mark is persistent: it is @emph{never} | |
360 | deactivated, but can be set to different locations using commands such | |
361 | as @kbd{C-@key{SPC}}. After the first time you set the mark in a | |
362 | buffer, there is always a region in that buffer. Emacs will not | |
0665a8b0 | 363 | highlight the region, because that would be a nuisance. As a special |
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364 | exception, the region is temporarily highlighted after it is set with |
365 | the mouse. | |
366 | ||
367 | To turn off Transient Mark mode, type @kbd{M-x transient-mark-mode}. | |
368 | This command toggles the mode; you can use the same command to turn | |
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369 | Transient Mark mode on again. You can also turn off Transient Mark |
370 | mode using the menu bar: in the @samp{Options} menu, toggle the | |
371 | @samp{Active Region Highlighting} menu item. | |
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372 | |
373 | Here are the details of how Emacs behaves when Transient Mark mode | |
374 | is off: | |
375 | ||
376 | @itemize @bullet | |
377 | @item | |
378 | Emacs does not show where the mark is located---you have to remember. | |
379 | The usual solution to this problem is to set the mark and then use it | |
380 | soon, before you forget where it is. Alternatively, you can check the | |
381 | location of the mark by using @kbd{C-x C-x}, which exchanges the | |
382 | positions of the point and the mark (@pxref{Setting Mark}). | |
383 | ||
384 | @item | |
385 | Many commands that insert text, such as @kbd{C-y} (@code{yank}), | |
386 | position point and the mark at opposite ends of the inserted text, so | |
387 | that the region consists of the text just inserted. You can tell when | |
388 | a command sets the mark because it displays @samp{Mark set} in the | |
389 | echo area. | |
390 | ||
391 | @item | |
392 | Many commands that move point long distances, like @kbd{M-<} and | |
393 | @kbd{C-s}, first set the mark where point was. | |
394 | ||
395 | @item | |
396 | Some commands that ordinarily operate on the region, if one exists, | |
397 | act instead on the entire buffer. For instance, @kbd{C-x u} normally | |
398 | reverses changes within the region if one exists; when Transient Mark | |
399 | mode is off, it acts on the entire buffer. However, you can type | |
400 | @kbd{C-u C-x u} to make it operate on the region. @xref{Undo}. Other | |
401 | commands that act this way are identified in their own documentation. | |
402 | @end itemize | |
403 | ||
404 | While Transient Mark mode is off, you can activate it temporarily | |
405 | using @kbd{C-@key{SPC} C-@key{SPC}} or @kbd{C-u C-x C-x}. | |
406 | ||
407 | @table @kbd | |
408 | @item C-@key{SPC} C-@key{SPC} | |
409 | @kindex C-@key{SPC} C-@key{SPC} | |
410 | Set the mark at point (like plain @kbd{C-@key{SPC}}) and enable | |
411 | Transient Mark mode just once, until the mark is deactivated. (This | |
412 | is not really a separate command; you are using the @kbd{C-@key{SPC}} | |
413 | command twice.) | |
414 | ||
415 | @item C-u C-x C-x | |
416 | @kindex C-u C-x C-x | |
417 | Activate the mark without changing it; enable Transient Mark mode just | |
418 | once, until the mark is deactivated. (This is the @kbd{C-x C-x} | |
419 | command, @code{exchange-point-and-mark}, with a prefix argument.) | |
420 | @end table | |
421 | ||
422 | These commands set or activate the mark, and enable Transient Mark | |
423 | mode only until the mark is deactivated. One reason you may want to | |
424 | use them is that some commands operate on the entire buffer instead of | |
425 | the region when Transient Mark mode is off. Enabling Transient Mark | |
426 | mode momentarily gives you a way to use these commands on the region. | |
6bf7aab6 | 427 | |
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428 | @ignore |
429 | arch-tag: f35e4d82-911b-4cfc-a3d7-3c87b2abba20 | |
430 | @end ignore |