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