Add @need before Deletion node.
[bpt/emacs.git] / man / killing.texi
1 @c This is part of the Emacs manual.
2 @c Copyright (C) 1985,86,87,93,94,95,97,00,2001 Free Software Foundation, Inc.
3 @c See file emacs.texi for copying conditions.
4 @iftex
5 @chapter Killing and Moving Text
6
7 @dfn{Killing} means erasing text and copying it into the @dfn{kill
8 ring}, from which it can be retrieved by @dfn{yanking} it. Some systems
9 use the terms ``cutting'' and ``pasting'' for these operations.
10
11 The commonest way of moving or copying text within Emacs is to kill it
12 and later yank it elsewhere in one or more places. This is very safe
13 because Emacs remembers several recent kills, not just the last one. It
14 is versatile, because the many commands for killing syntactic units can
15 also be used for moving those units. But there are other ways of
16 copying text for special purposes.
17
18 Emacs has only one kill ring for all buffers, so you can kill text in
19 one buffer and yank it in another buffer.
20
21 @end iftex
22
23 @node Killing, Yanking, Mark, Top
24 @section Deletion and Killing
25
26 @cindex killing text
27 @cindex cutting text
28 @cindex deletion
29 Most commands which erase text from the buffer save it in the kill
30 ring so that you can move or copy it to other parts of the buffer.
31 These commands are known as @dfn{kill} commands. The rest of the
32 commands that erase text do not save it in the kill ring; they are known
33 as @dfn{delete} commands. (This distinction is made only for erasure of
34 text in the buffer.) If you do a kill or delete command by mistake, you
35 can use the @kbd{C-x u} (@code{undo}) command to undo it
36 (@pxref{Undo}).
37
38 @vindex kill-read-only-ok
39 @cindex read-only text, killing
40 You cannot kill read-only text, since such text does not allow any
41 kind of modification. But some users like to use the kill commands to
42 copy read-only text into the kill ring, without actually changing it.
43 If you set the variable @code{kill-read-only-ok} to a non-@code{nil}
44 value, the kill commands work specially in a read-only buffer: they
45 move over text, and copy it to the kill ring, without actually
46 deleting it from the buffer. When this happens, a message in the echo
47 area tells you what is happening.
48
49 The delete commands include @kbd{C-d} (@code{delete-char}) and
50 @key{DEL} (@code{delete-backward-char}), which delete only one character at
51 a time, and those commands that delete only spaces or newlines. Commands
52 that can destroy significant amounts of nontrivial data generally kill.
53 The commands' names and individual descriptions use the words @samp{kill}
54 and @samp{delete} to say which they do.
55
56 @cindex Delete Selection mode
57 @cindex mode, Delete Selection
58 @findex delete-selection-mode
59 Many window systems follow the convention that insertion while text
60 is selected deletes the selected text. You can make Emacs behave this
61 way by enabling Delete Selection mode, with @kbd{M-x
62 delete-selection-mode}, or using Custom. Another effect of this mode
63 is that @key{DEL}, @kbd{C-d} and some other keys, when a selection
64 exists, will kill the whole selection. It also enables Transient Mark
65 mode (@pxref{Transient Mark}).
66
67 @menu
68 * Deletion:: Commands for deleting small amounts of text and
69 blank areas.
70 * Killing by Lines:: How to kill entire lines of text at one time.
71 * Other Kill Commands:: Commands to kill large regions of text and
72 syntactic units such as words and sentences.
73 @end menu
74
75 @need 1500
76 @node Deletion
77 @subsection Deletion
78 @findex delete-backward-char
79 @findex delete-char
80
81 @table @kbd
82 @item C-d
83 @itemx @key{Delete}
84 Delete next character (@code{delete-char}). If your keyboard has a
85 @key{Delete} function key (usually located in the edit keypad), Emacs
86 binds it to @code{delete-char} as well.
87 @item @key{DEL}
88 @itemx @key{BS}
89 Delete previous character (@code{delete-backward-char}). Some keyboards
90 refer to this key as a ``backspace key'' and label it with a left arrow.
91 @item M-\
92 Delete spaces and tabs around point (@code{delete-horizontal-space}).
93 @item M-@key{SPC}
94 Delete spaces and tabs around point, leaving one space
95 (@code{just-one-space}).
96 @item C-x C-o
97 Delete blank lines around the current line (@code{delete-blank-lines}).
98 @item M-^
99 Join two lines by deleting the intervening newline, along with any
100 indentation following it (@code{delete-indentation}).
101 @end table
102
103 @kindex DEL
104 @kindex C-d
105 The most basic delete commands are @kbd{C-d} (@code{delete-char}) and
106 @key{DEL} (@code{delete-backward-char}). @kbd{C-d} deletes the
107 character after point, the one the cursor is ``on top of.'' This
108 doesn't move point. @key{DEL} deletes the character before the cursor,
109 and moves point back. You can delete newlines like any other characters
110 in the buffer; deleting a newline joins two lines. Actually, @kbd{C-d}
111 and @key{DEL} aren't always delete commands; when given arguments, they
112 kill instead, since they can erase more than one character this way.
113
114 @kindex BACKSPACE
115 @kindex BS
116 @kindex DELETE
117 Every keyboard has a large key, labeled @key{DEL}, @key{BACKSPACE},
118 @key{BS} or @key{DELETE}, which is a short distance above the
119 @key{RET} or @key{ENTER} key and is normally used for erasing what you
120 have typed. Regardless of the actual name on the key, in Emacs it is
121 equivalent to @key{DEL}---or it should be.
122
123 Many keyboards (including standard PC keyboards) have a
124 @key{BACKSPACE} key a short ways above @key{RET} or @key{ENTER}, and a
125 @key{DELETE} key elsewhere. In that case, the @key{BACKSPACE} key is
126 @key{DEL}, and the @key{DELETE} key is equivalent to @kbd{C-d}---or it
127 should be.
128
129 Why do we say ``or it should be''? When Emacs starts up using a
130 window system, it determines automatically which key or keys should be
131 equivalent to @key{DEL}. So the @key{BACKSPACE} and/or @key{DELETE}
132 keys normally do the right things. But in some unusual cases Emacs
133 gets the wrong information from the system. If these keys don't do
134 what they ought to do, you need to tell Emacs which key to use for
135 @key{DEL}. @xref{DEL Gets Help}, for how to do this.
136
137 @findex normal-erase-is-backspace-mode
138 On most text-only terminals, Emacs cannot tell which keys the
139 keyboard really has, so it follows a uniform plan which may or may not
140 fit your keyboard. The uniform plan is that the ASCII @key{DEL}
141 character deletes, and the ASCII @key{BS} (backspace) character asks
142 for help (it is the same as @kbd{C-h}). If this is not right for your
143 keyboard, if you find that the key which ought to delete backwards
144 enters Help instead, see @ref{DEL Gets Help}.
145
146 @kindex M-\
147 @findex delete-horizontal-space
148 @kindex M-SPC
149 @findex just-one-space
150 The other delete commands are those which delete only whitespace
151 characters: spaces, tabs and newlines. @kbd{M-\}
152 (@code{delete-horizontal-space}) deletes all the spaces and tab
153 characters before and after point. @kbd{M-@key{SPC}}
154 (@code{just-one-space}) does likewise but leaves a single space after
155 point, regardless of the number of spaces that existed previously (even
156 zero).
157
158 @kbd{C-x C-o} (@code{delete-blank-lines}) deletes all blank lines
159 after the current line. If the current line is blank, it deletes all
160 blank lines preceding the current line as well (leaving one blank line,
161 the current line).
162
163 @kbd{M-^} (@code{delete-indentation}) joins the current line and the
164 previous line, by deleting a newline and all surrounding spaces, usually
165 leaving a single space. @xref{Indentation,M-^}.
166
167 @node Killing by Lines
168 @subsection Killing by Lines
169
170 @table @kbd
171 @item C-k
172 Kill rest of line or one or more lines (@code{kill-line}).
173 @end table
174
175 @kindex C-k
176 @findex kill-line
177 The simplest kill command is @kbd{C-k}. If given at the beginning of
178 a line, it kills all the text on the line, leaving it blank. When used
179 on a blank line, it kills the whole line including its newline. To kill
180 an entire non-blank line, go to the beginning and type @kbd{C-k} twice.
181
182 More generally, @kbd{C-k} kills from point up to the end of the line,
183 unless it is at the end of a line. In that case it kills the newline
184 following point, thus merging the next line into the current one.
185 Spaces and tabs that you can't see at the end of the line are ignored
186 when deciding which case applies, so if point appears to be at the end
187 of the line, you can be sure @kbd{C-k} will kill the newline.
188
189 When @kbd{C-k} is given a positive argument, it kills that many lines
190 and the newlines that follow them (however, text on the current line
191 before point is spared). With a negative argument @minus{}@var{n}, it
192 kills @var{n} lines preceding the current line (together with the text
193 on the current line before point). Thus, @kbd{C-u - 2 C-k} at the front
194 of a line kills the two previous lines.
195
196 @kbd{C-k} with an argument of zero kills the text before point on the
197 current line.
198
199 @vindex kill-whole-line
200 If the variable @code{kill-whole-line} is non-@code{nil}, @kbd{C-k} at
201 the very beginning of a line kills the entire line including the
202 following newline. This variable is normally @code{nil}.
203
204 @node Other Kill Commands
205 @subsection Other Kill Commands
206 @findex kill-region
207 @kindex C-w
208
209 @c DoubleWideCommands
210 @table @kbd
211 @item C-w
212 Kill region (from point to the mark) (@code{kill-region}).
213 @item M-d
214 Kill word (@code{kill-word}). @xref{Words}.
215 @item M-@key{DEL}
216 Kill word backwards (@code{backward-kill-word}).
217 @item C-x @key{DEL}
218 Kill back to beginning of sentence (@code{backward-kill-sentence}).
219 @xref{Sentences}.
220 @item M-k
221 Kill to end of sentence (@code{kill-sentence}).
222 @item C-M-k
223 Kill sexp (@code{kill-sexp}). @xref{Lists}.
224 @item M-z @var{char}
225 Kill through the next occurrence of @var{char} (@code{zap-to-char}).
226 @end table
227
228 A kill command which is very general is @kbd{C-w}
229 (@code{kill-region}), which kills everything between point and the
230 mark. With this command, you can kill any contiguous sequence of
231 characters, if you first set the region around them.
232
233 @kindex M-z
234 @findex zap-to-char
235 A convenient way of killing is combined with searching: @kbd{M-z}
236 (@code{zap-to-char}) reads a character and kills from point up to (and
237 including) the next occurrence of that character in the buffer. A
238 numeric argument acts as a repeat count. A negative argument means to
239 search backward and kill text before point.
240
241 Other syntactic units can be killed: words, with @kbd{M-@key{DEL}} and
242 @kbd{M-d} (@pxref{Words}); sexps, with @kbd{C-M-k} (@pxref{Lists}); and
243 sentences, with @kbd{C-x @key{DEL}} and @kbd{M-k}
244 (@pxref{Sentences}).@refill
245
246 You can use kill commands in read-only buffers. They don't actually
247 change the buffer, and they beep to warn you of that, but they do copy
248 the text you tried to kill into the kill ring, so you can yank it into
249 other buffers. Most of the kill commands move point across the text
250 they copy in this way, so that successive kill commands build up a
251 single kill ring entry as usual.
252
253 @node Yanking, Accumulating Text, Killing, Top
254 @section Yanking
255 @cindex moving text
256 @cindex copying text
257 @cindex kill ring
258 @cindex yanking
259 @cindex pasting
260
261 @dfn{Yanking} means reinserting text previously killed. This is what
262 some systems call ``pasting.'' The usual way to move or copy text is to
263 kill it and then yank it elsewhere one or more times.
264
265 @table @kbd
266 @item C-y
267 Yank last killed text (@code{yank}).
268 @item M-y
269 Replace text just yanked with an earlier batch of killed text
270 (@code{yank-pop}).
271 @item M-w
272 Save region as last killed text without actually killing it
273 (@code{kill-ring-save}).
274 @item C-M-w
275 Append next kill to last batch of killed text (@code{append-next-kill}).
276 @end table
277
278 @menu
279 * Kill Ring:: Where killed text is stored. Basic yanking.
280 * Appending Kills:: Several kills in a row all yank together.
281 * Earlier Kills:: Yanking something killed some time ago.
282 @end menu
283
284 @node Kill Ring
285 @subsection The Kill Ring
286
287 All killed text is recorded in the @dfn{kill ring}, a list of blocks of
288 text that have been killed. There is only one kill ring, shared by all
289 buffers, so you can kill text in one buffer and yank it in another buffer.
290 This is the usual way to move text from one file to another.
291 (@xref{Accumulating Text}, for some other ways.)
292
293 @kindex C-y
294 @findex yank
295 The command @kbd{C-y} (@code{yank}) reinserts the text of the most recent
296 kill. It leaves the cursor at the end of the text. It sets the mark at
297 the beginning of the text. @xref{Mark}.
298
299 @kbd{C-u C-y} leaves the cursor in front of the text, and sets the
300 mark after it. This happens only if the argument is specified with just
301 a @kbd{C-u}, precisely. Any other sort of argument, including @kbd{C-u}
302 and digits, specifies an earlier kill to yank (@pxref{Earlier Kills}).
303
304 @kindex M-w
305 @findex kill-ring-save
306 To copy a block of text, you can use @kbd{M-w}
307 (@code{kill-ring-save}), which copies the region into the kill ring
308 without removing it from the buffer. This is approximately equivalent
309 to @kbd{C-w} followed by @kbd{C-x u}, except that @kbd{M-w} does not
310 alter the undo history and does not temporarily change the screen.
311
312 @node Appending Kills
313 @subsection Appending Kills
314
315 @cindex appending kills in the ring
316 @cindex television
317 Normally, each kill command pushes a new entry onto the kill ring.
318 However, two or more kill commands in a row combine their text into a
319 single entry, so that a single @kbd{C-y} yanks all the text as a unit,
320 just as it was before it was killed.
321
322 Thus, if you want to yank text as a unit, you need not kill all of it
323 with one command; you can keep killing line after line, or word after
324 word, until you have killed it all, and you can still get it all back at
325 once.
326
327 Commands that kill forward from point add onto the end of the previous
328 killed text. Commands that kill backward from point add text onto the
329 beginning. This way, any sequence of mixed forward and backward kill
330 commands puts all the killed text into one entry without rearrangement.
331 Numeric arguments do not break the sequence of appending kills. For
332 example, suppose the buffer contains this text:
333
334 @example
335 This is a line @point{}of sample text.
336 @end example
337
338 @noindent
339 with point shown by @point{}. If you type @kbd{M-d M-@key{DEL} M-d
340 M-@key{DEL}}, killing alternately forward and backward, you end up with
341 @samp{a line of sample} as one entry in the kill ring, and @samp{This
342 is@ @ text.} in the buffer. (Note the double space, which you can clean
343 up with @kbd{M-@key{SPC}} or @kbd{M-q}.)
344
345 Another way to kill the same text is to move back two words with
346 @kbd{M-b M-b}, then kill all four words forward with @kbd{C-u M-d}.
347 This produces exactly the same results in the buffer and in the kill
348 ring. @kbd{M-f M-f C-u M-@key{DEL}} kills the same text, all going
349 backward; once again, the result is the same. The text in the kill ring
350 entry always has the same order that it had in the buffer before you
351 killed it.
352
353 @kindex C-M-w
354 @findex append-next-kill
355 If a kill command is separated from the last kill command by other
356 commands (not just numeric arguments), it starts a new entry on the kill
357 ring. But you can force it to append by first typing the command
358 @kbd{C-M-w} (@code{append-next-kill}) right before it. The @kbd{C-M-w}
359 tells the following command, if it is a kill command, to append the text
360 it kills to the last killed text, instead of starting a new entry. With
361 @kbd{C-M-w}, you can kill several separated pieces of text and
362 accumulate them to be yanked back in one place.@refill
363
364 A kill command following @kbd{M-w} does not append to the text that
365 @kbd{M-w} copied into the kill ring.
366
367 @node Earlier Kills
368 @subsection Yanking Earlier Kills
369
370 @cindex yanking previous kills
371 @kindex M-y
372 @findex yank-pop
373 To recover killed text that is no longer the most recent kill, use the
374 @kbd{M-y} command (@code{yank-pop}). It takes the text previously
375 yanked and replaces it with the text from an earlier kill. So, to
376 recover the text of the next-to-the-last kill, first use @kbd{C-y} to
377 yank the last kill, and then use @kbd{M-y} to replace it with the
378 previous kill. @kbd{M-y} is allowed only after a @kbd{C-y} or another
379 @kbd{M-y}.
380
381 You can understand @kbd{M-y} in terms of a ``last yank'' pointer which
382 points at an entry in the kill ring. Each time you kill, the ``last
383 yank'' pointer moves to the newly made entry at the front of the ring.
384 @kbd{C-y} yanks the entry which the ``last yank'' pointer points to.
385 @kbd{M-y} moves the ``last yank'' pointer to a different entry, and the
386 text in the buffer changes to match. Enough @kbd{M-y} commands can move
387 the pointer to any entry in the ring, so you can get any entry into the
388 buffer. Eventually the pointer reaches the end of the ring; the next
389 @kbd{M-y} moves it to the first entry again.
390
391 @kbd{M-y} moves the ``last yank'' pointer around the ring, but it does
392 not change the order of the entries in the ring, which always runs from
393 the most recent kill at the front to the oldest one still remembered.
394
395 @kbd{M-y} can take a numeric argument, which tells it how many entries
396 to advance the ``last yank'' pointer by. A negative argument moves the
397 pointer toward the front of the ring; from the front of the ring, it
398 moves ``around'' to the last entry and continues forward from there.
399
400 Once the text you are looking for is brought into the buffer, you can
401 stop doing @kbd{M-y} commands and it will stay there. It's just a copy
402 of the kill ring entry, so editing it in the buffer does not change
403 what's in the ring. As long as no new killing is done, the ``last
404 yank'' pointer remains at the same place in the kill ring, so repeating
405 @kbd{C-y} will yank another copy of the same previous kill.
406
407 If you know how many @kbd{M-y} commands it would take to find the text
408 you want, you can yank that text in one step using @kbd{C-y} with a
409 numeric argument. @kbd{C-y} with an argument restores the text the
410 specified number of entries back in the kill ring. Thus, @kbd{C-u 2
411 C-y} gets the next-to-the-last block of killed text. It is equivalent
412 to @kbd{C-y M-y}. @kbd{C-y} with a numeric argument starts counting
413 from the ``last yank'' pointer, and sets the ``last yank'' pointer to
414 the entry that it yanks.
415
416 @vindex kill-ring-max
417 The length of the kill ring is controlled by the variable
418 @code{kill-ring-max}; no more than that many blocks of killed text are
419 saved.
420
421 @vindex kill-ring
422 The actual contents of the kill ring are stored in a variable named
423 @code{kill-ring}; you can view the entire contents of the kill ring with
424 the command @kbd{C-h v kill-ring}.
425
426 @node Accumulating Text, Rectangles, Yanking, Top
427 @section Accumulating Text
428 @findex append-to-buffer
429 @findex prepend-to-buffer
430 @findex copy-to-buffer
431 @findex append-to-file
432
433 @cindex accumulating scattered text
434 Usually we copy or move text by killing it and yanking it, but there
435 are other methods convenient for copying one block of text in many
436 places, or for copying many scattered blocks of text into one place. To
437 copy one block to many places, store it in a register
438 (@pxref{Registers}). Here we describe the commands to accumulate
439 scattered pieces of text into a buffer or into a file.
440
441 @table @kbd
442 @item M-x append-to-buffer
443 Append region to contents of specified buffer.
444 @item M-x prepend-to-buffer
445 Prepend region to contents of specified buffer.
446 @item M-x copy-to-buffer
447 Copy region into specified buffer, deleting that buffer's old contents.
448 @item M-x insert-buffer
449 Insert contents of specified buffer into current buffer at point.
450 @item M-x append-to-file
451 Append region to contents of specified file, at the end.
452 @end table
453
454 To accumulate text into a buffer, use @kbd{M-x append-to-buffer}.
455 This reads a buffer name, then inserts a copy of the region into the
456 buffer specified. If you specify a nonexistent buffer,
457 @code{append-to-buffer} creates the buffer. The text is inserted
458 wherever point is in that buffer. If you have been using the buffer for
459 editing, the copied text goes into the middle of the text of the buffer,
460 wherever point happens to be in it.
461
462 Point in that buffer is left at the end of the copied text, so
463 successive uses of @code{append-to-buffer} accumulate the text in the
464 specified buffer in the same order as they were copied. Strictly
465 speaking, @code{append-to-buffer} does not always append to the text
466 already in the buffer---it appends only if point in that buffer is at the end.
467 However, if @code{append-to-buffer} is the only command you use to alter
468 a buffer, then point is always at the end.
469
470 @kbd{M-x prepend-to-buffer} is just like @code{append-to-buffer}
471 except that point in the other buffer is left before the copied text, so
472 successive prependings add text in reverse order. @kbd{M-x
473 copy-to-buffer} is similar except that any existing text in the other
474 buffer is deleted, so the buffer is left containing just the text newly
475 copied into it.
476
477 To retrieve the accumulated text from another buffer, use the command
478 @kbd{M-x insert-buffer}; this too takes @var{buffername} as an argument.
479 It inserts a copy of the text in buffer @var{buffername} into the
480 selected buffer. You can alternatively select the other buffer for
481 editing, then optionally move text from it by killing. @xref{Buffers},
482 for background information on buffers.
483
484 Instead of accumulating text within Emacs, in a buffer, you can append
485 text directly into a file with @kbd{M-x append-to-file}, which takes
486 @var{filename} as an argument. It adds the text of the region to the end
487 of the specified file. The file is changed immediately on disk.
488
489 You should use @code{append-to-file} only with files that are
490 @emph{not} being visited in Emacs. Using it on a file that you are
491 editing in Emacs would change the file behind Emacs's back, which
492 can lead to losing some of your editing.
493
494 @node Rectangles, Registers, Accumulating Text, Top
495 @section Rectangles
496 @cindex rectangle
497 @cindex columns (and rectangles)
498 @cindex killing rectangular areas of text
499
500 The rectangle commands operate on rectangular areas of the text: all
501 the characters between a certain pair of columns, in a certain range of
502 lines. Commands are provided to kill rectangles, yank killed rectangles,
503 clear them out, fill them with blanks or text, or delete them. Rectangle
504 commands are useful with text in multicolumn formats, and for changing
505 text into or out of such formats.
506
507 When you must specify a rectangle for a command to work on, you do it
508 by putting the mark at one corner and point at the opposite corner. The
509 rectangle thus specified is called the @dfn{region-rectangle} because
510 you control it in about the same way the region is controlled. But
511 remember that a given combination of point and mark values can be
512 interpreted either as a region or as a rectangle, depending on the
513 command that uses them.
514
515 If point and the mark are in the same column, the rectangle they
516 delimit is empty. If they are in the same line, the rectangle is one
517 line high. This asymmetry between lines and columns comes about
518 because point (and likewise the mark) is between two columns, but within
519 a line.
520
521 @table @kbd
522 @item C-x r k
523 Kill the text of the region-rectangle, saving its contents as the
524 ``last killed rectangle'' (@code{kill-rectangle}).
525 @item C-x r d
526 Delete the text of the region-rectangle (@code{delete-rectangle}).
527 @item C-x r y
528 Yank the last killed rectangle with its upper left corner at point
529 (@code{yank-rectangle}).
530 @item C-x r o
531 Insert blank space to fill the space of the region-rectangle
532 (@code{open-rectangle}). This pushes the previous contents of the
533 region-rectangle rightward.
534 @item M-x clear-rectangle
535 Clear the region-rectangle by replacing its contents with spaces.
536 @item M-x delete-whitespace-rectangle
537 Delete whitespace in each of the lines on the specified rectangle,
538 starting from the left edge column of the rectangle.
539 @item C-x r t @var{string} @key{RET}
540 Replace rectangle contents with @var{string} on each line.
541 (@code{string-rectangle}).
542 @item M-x replace-rectangle @key{RET} @var{string} @key{RET}
543 Replaces each line of the region-rectangle with @var{string}
544 (@code{string-rectangle}).
545 @item M-x string-insert-rectangle @key{RET} @var{string} @key{RET}
546 Insert @var{STRING} on each line of the rectangle.
547 @end table
548
549 The rectangle operations fall into two classes: commands deleting and
550 inserting rectangles, and commands for blank rectangles.
551
552 @kindex C-x r k
553 @kindex C-x r d
554 @findex kill-rectangle
555 @findex delete-rectangle
556 There are two ways to get rid of the text in a rectangle: you can
557 discard the text (delete it) or save it as the ``last killed''
558 rectangle. The commands for these two ways are @kbd{C-x r d}
559 (@code{delete-rectangle}) and @kbd{C-x r k} (@code{kill-rectangle}). In
560 either case, the portion of each line that falls inside the rectangle's
561 boundaries is deleted, causing following text (if any) on the line to
562 move left into the gap.
563
564 Note that ``killing'' a rectangle is not killing in the usual sense; the
565 rectangle is not stored in the kill ring, but in a special place that
566 can only record the most recent rectangle killed. This is because yanking
567 a rectangle is so different from yanking linear text that different yank
568 commands have to be used and yank-popping is hard to make sense of.
569
570 @kindex C-x r y
571 @findex yank-rectangle
572 To yank the last killed rectangle, type @kbd{C-x r y}
573 (@code{yank-rectangle}). Yanking a rectangle is the opposite of killing
574 one. Point specifies where to put the rectangle's upper left corner.
575 The rectangle's first line is inserted there, the rectangle's second
576 line is inserted at a position one line vertically down, and so on. The
577 number of lines affected is determined by the height of the saved
578 rectangle.
579
580 You can convert single-column lists into double-column lists using
581 rectangle killing and yanking; kill the second half of the list as a
582 rectangle and then yank it beside the first line of the list.
583 @xref{Two-Column}, for another way to edit multi-column text.
584
585 You can also copy rectangles into and out of registers with @kbd{C-x r
586 r @var{r}} and @kbd{C-x r i @var{r}}. @xref{RegRect,,Rectangle
587 Registers}.
588
589 @kindex C-x r o
590 @findex open-rectangle
591 @findex clear-rectangle
592 There are two commands you can use for making blank rectangles:
593 @kbd{M-x clear-rectangle} which blanks out existing text, and @kbd{C-x r
594 o} (@code{open-rectangle}) which inserts a blank rectangle. Clearing a
595 rectangle is equivalent to deleting it and then inserting a blank
596 rectangle of the same size.
597
598 @findex delete-whitespace-rectangle
599 The command @kbd{M-x delete-whitespace-rectangle} deletes horizontal
600 whitespace starting from a particular column. This applies to each of
601 the lines in the rectangle, and the column is specified by the left
602 edge of the rectangle. The right edge of the rectangle does not make
603 any difference to this command.
604
605 @kindex C-x r t
606 @findex string-rectangle
607 @findex replace-rectangle
608 The command @kbd{C-x r t} (@code{M-x string-rectangle}) replaces the
609 contents of a region-rectangle with a string on each line. The
610 string's width need not be the same as the width of the rectangle. If
611 the string's width is less, the text after the rectangle shifts left;
612 if the string is wider than the rectangle, the text after the
613 rectangle shifts right.
614
615 @findex string-insert-rectangle
616 The command @kbd{M-x string-insert-rectangle} is similar to
617 @code{string-rectangle}, but inserts the string on each line,
618 shifting the original text to the right.