In Emacs, killing means erasing text and copying it into the kill ring. Yanking means bringing text from the kill ring back into the buffer. (Some applications use the terms “cutting” and “pasting” for similar operations.) The kill ring is so-named because it can be visualized as a set of blocks of text arranged in a ring, which you can access in cyclic order. See The Kill Ring.
Killing and yanking are the most common way to move or copy text within Emacs. It is very versatile, because there are commands for killing many different types of syntactic units.
Most commands which erase text from the buffer save it in the kill
ring (see The Kill Ring). These are known as kill commands, and
their names normally contain the word ‘kill’ (e.g.,
kill-line). The kill ring stores several recent kills, not
just the last one, so killing is a very safe operation: you don’t have
to worry much about losing text that you previously killed. The kill
ring is shared by all buffers, so text that is killed in one buffer
can be yanked into another buffer.
When you use C-/ (undo) to undo a kill command
(see Undo), that brings the killed text back into the buffer, but
does not remove it from the kill ring.
On graphical displays, killing text also copies it to the system clipboard. See “Cut and Paste” Operations on Graphical Displays.
Commands that erase text but do not save it in the kill ring are
known as delete commands; their names usually contain the word
‘delete’. These include C-d (delete-char) and
DEL (delete-backward-char), which delete only one
character at a time, and those commands that delete only spaces or
newlines. Commands that can erase significant amounts of nontrivial
data generally do a kill operation instead.
You can also use the mouse to kill and yank. See “Cut and Paste” Operations on Graphical Displays.
Deletion means erasing text and not saving it in the kill ring. For the most part, the Emacs commands that delete text are those that erase just one character or only whitespace.
Delete the previous character, or the text in the region if it is
active (delete-backward-char).
Delete the next character, or the text in the region if it is active
(delete-forward-char).
Delete the next character (delete-char).
Delete spaces and tabs around point (delete-horizontal-space).
Delete spaces and tabs around point, leaving one space.
Delete spaces and tabs around point in flexible ways
(cycle-spacing).
Delete blank lines around the current line (delete-blank-lines).
Join two lines by deleting the intervening newline, along with any
indentation following it (delete-indentation).
We have already described the basic deletion commands DEL
(delete-backward-char), delete
(delete-forward-char), and C-d (delete-char).
See Erasing Text. With a numeric argument, they delete the specified
number of characters. If the numeric argument is omitted or one,
DEL and delete delete all the text in the region if it is
active (see Operating on the Region).
The other delete commands are those that delete only whitespace
characters: spaces, tabs and newlines. M-\
(delete-horizontal-space) deletes all the spaces and tab
characters before and after point. With a prefix argument, this only
deletes spaces and tab characters before point.
M-x just-one-space deletes tabs and spaces around point, but leaves a single space before point, regardless of the number of spaces that existed previously (even if there were none before). With a numeric argument n, it leaves n spaces before point if n is positive; if n is negative, it deletes newlines in addition to spaces and tabs, leaving −n spaces before point.
The command cycle-spacing (M-SPC) acts like a more
flexible version of just-one-space. It performs different
space cleanup actions defined by cycle-spacing-actions, in a
cyclic manner, if you call it repeatedly in succession. By default,
the first invocation does the same as just-one-space, the
second deletes all whitespace characters around point like
delete-horizontal-space, and the third restores the original
whitespace characters; then it cycles. If invoked with a prefix
argument, each action is given that value of the argument. The user
option cycle-spacing-actions can include other members; see the
doc string of that option for the details.
C-x C-o (delete-blank-lines) deletes all blank lines
after the current line. If the current line is blank, it deletes all
blank lines preceding the current line as well (leaving one blank line,
the current line). On a solitary blank line, it deletes that line.
M-^ (delete-indentation) joins the current line and the
previous line, by deleting a newline and all surrounding spaces, usually
leaving a single space. See M-^.
The command delete-duplicate-lines searches the region for
identical lines, and removes all but one copy of each. Normally it
keeps the first instance of each repeated line, but with a C-u
prefix argument it keeps the last. With a C-u C-u prefix
argument, it only searches for adjacent identical lines. This is a
more efficient mode of operation, useful when the lines have already
been sorted. With a C-u C-u C-u prefix argument, it retains
repeated blank lines.
Kill rest of line or one or more lines (kill-line).
Kill an entire line at once (kill-whole-line)
The simplest kill command is C-k (kill-line). If used
at the end of a line, it kills the line-ending newline character,
merging the next line into the current one (thus, a blank line is
entirely removed). Otherwise, C-k kills all the text from point
up to the end of the line; if point was originally at the beginning of
the line, this leaves the line blank.
Spaces and tabs at the end of the line are ignored when deciding which case applies. As long as point is after the last non-whitespace character in the line, you can be sure that C-k will kill the newline. To kill an entire non-blank line, go to the beginning and type C-k twice.
In this context, “line” means a logical text line, not a screen line (see Continuation Lines).
When C-k is given a positive argument n, it kills n lines and the newlines that follow them (text on the current line before point is not killed). With a negative argument −n, it kills n lines preceding the current line, together with the text on the current line before point. C-k with an argument of zero kills the text before point on the current line.
If the variable kill-whole-line is non-nil, C-k at
the very beginning of a line kills the entire line including the
following newline. This variable is normally nil.
C-S-backspace (kill-whole-line) kills a whole line
including its newline, regardless of the position of point within the
line. Note that many text terminals will prevent you from typing the
key sequence C-S-backspace.
Kill the region (kill-region).
Copy the region into the kill ring (kill-ring-save).
Kill the next word (kill-word). See Words.
Kill one word backwards (backward-kill-word).
Kill back to beginning of sentence (backward-kill-sentence).
See Sentences.
Kill to the end of the sentence (kill-sentence).
Kill the following balanced expression (kill-sexp). See Expressions with Balanced Parentheses.
Kill through the next occurrence of char (zap-to-char).
Kill up to, but not including, the next occurrence of char.
One of the commonly-used kill commands is C-w
(kill-region), which kills the text in the region
(see The Mark and the Region). Similarly, M-w (kill-ring-save) copies
the text in the region into the kill ring without removing it from the
buffer. If the mark is inactive when you type C-w or M-w,
the command acts on the text between point and where you last set the
mark (see Operating on the Region).
Emacs also provides commands to kill specific syntactic units: words, with M-DEL and M-d (see Words); balanced expressions, with C-M-k (see Expressions with Balanced Parentheses); and sentences, with C-x DEL and M-k (see Sentences).
The command M-z (zap-to-char) combines killing with
searching: it reads a character and kills from point up to (and
including) the next occurrence of that character in the buffer. A
numeric argument acts as a repeat count; a negative argument means to
search backward and kill text before point. A history of previously
used characters is maintained and can be accessed via the
M-p/M-n keystrokes. This is mainly useful if the
character to be used has to be entered via a complicated input method.
A similar command zap-up-to-char kills from point up to, but
not including the next occurrence of a character, with numeric
argument acting as a repeat count.
Some specialized buffers contain read-only text, which cannot
be modified and therefore cannot be killed. The kill commands work
specially in a read-only buffer: they move over text and copy it to
the kill ring, without actually deleting it from the buffer.
Normally, they also beep and display an error message when this
happens. But if you set the variable kill-read-only-ok to a
non-nil value, they just print a message in the echo area to
explain why the text has not been erased.
Before saving the kill to the kill ring, you can transform the
string using kill-transform-function. It’s called with the
string to be killed, and it should return the string you want to be
saved. It can also return nil, in which case the string won’t
be saved to the kill ring. For instance, if you never want to save
a pure white space string to the kill ring, you can say:
(setq kill-transform-function
(lambda (string)
(and (not (string-blank-p string))
string)))
If you change the variable kill-do-not-save-duplicates to a
non-nil value, identical subsequent kills yield a single
kill-ring entry, without duplication.
If you enable the minor mode kill-ring-deindent-mode, text
saved to the kill-ring will have its indentation decreased by the amount
of indentation of the first saved line. That is, if the first line of
the saved text was indented n columns, this mode will remove that
number of columns from the indentation of each saved line.
Yanking means reinserting text previously killed. The usual way to move or copy text is to kill it and then yank it elsewhere.
Yank the last kill into the buffer, at point (yank).
Either replace the text just yanked with an earlier batch of killed
text (yank-pop), or allow selecting from the list of
previously-killed batches of text. See Yanking Earlier Kills.
Cause the following command, if it is a kill command, to append to the
previous kill (append-next-kill). See Appending Kills.
The basic yanking command is C-y (yank). It inserts
the most recent kill, leaving the cursor at the end of the inserted
text. It also sets the mark at the beginning of the inserted text,
without activating the mark; this lets you jump easily to that
position, if you wish, with C-u C-SPC (see The Mark Ring).
With a plain prefix argument (C-u C-y), the command instead leaves the cursor in front of the inserted text, and sets the mark at the end. Using any other prefix argument specifies an earlier kill; e.g., C-u 4 C-y reinserts the fourth most recent kill. See Yanking Earlier Kills.
On graphical displays and on capable text-mode displays, C-y first checks if another application has placed any text in the system clipboard more recently than the last Emacs kill. If so, it inserts the clipboard’s text instead. Thus, Emacs effectively treats “cut” or “copy” clipboard operations performed in other applications like Emacs kills, except that they are not recorded in the kill ring. See “Cut and Paste” Operations on Graphical Displays, for details.
The kill ring is a list of blocks of text that were previously killed. There is only one kill ring, shared by all buffers, so you can kill text in one buffer and yank it in another buffer. This is the usual way to move text from one buffer to another. (There are several other methods: for instance, you could store the text in a register; see Registers. See Accumulating Text, for some other ways to move text around.)
The maximum number of entries in the kill ring is controlled by the
variable kill-ring-max. The default is 120. If you make a new
kill when this limit has been reached, Emacs makes room by deleting
the oldest entry in the kill ring.
The actual contents of the kill ring are stored in a variable named
kill-ring; you can view the entire contents of the kill ring
with C-h v kill-ring.
As explained in Yanking, you can use a numeric argument to
C-y to yank text that is no longer the most recent kill. This
is useful if you remember which kill ring entry you want. If you
don’t, you can use the M-y (yank-pop) command to cycle
through the possibilities or to select one of the earlier kills.
If the previous command was a yank command, M-y takes the text that was yanked and replaces it with the text from an earlier kill. So, to recover the text of the next-to-the-last kill, first use C-y to yank the last kill, and then use M-y to replace it with the previous kill. This works only after a C-y or another M-y. (If M-y is invoked after some other command, it works differently, see below.)
You can understand this operation mode of M-y in terms of a last-yank pointer which points at an entry in the kill ring. Each time you kill, the last-yank pointer moves to the newly made entry at the front of the ring. C-y yanks the entry which the last-yank pointer points to. M-y after a C-y or another M-y moves the last-yank pointer to the previous entry, and the text in the buffer changes to match. Enough M-y commands one after another can move the pointer to any entry in the ring, so you can get any entry into the buffer. Eventually the pointer reaches the end of the ring; the next M-y loops back around to the first entry again.
M-y moves the last-yank pointer around the ring, but it does not change the order of the entries in the ring, which always runs from the most recent kill at the front to the oldest one still remembered.
When used after C-y or M-y, M-y can take a numeric argument, which tells it how many entries to advance the last-yank pointer by. A negative argument moves the pointer toward the front of the ring; from the front of the ring, it moves around to the last entry and continues forward from there.
Once the text you are looking for is brought into the buffer, you can stop doing M-y commands and the last yanked text will stay there. It’s just a copy of the kill ring entry, so editing it in the buffer does not change what’s in the ring. As long as no new killing is done, the last-yank pointer remains at the same place in the kill ring, so repeating C-y will yank another copy of the same previous kill.
When you call C-y with a numeric argument, that also sets the last-yank pointer to the entry that it yanks.
You can also invoke M-y after a command that is not a yank command. In that case, M-y prompts you in the minibuffer for one of the previous kills. You can use the minibuffer history commands (see Minibuffer History) to navigate or search through the entries in the kill ring until you find the one you want to reinsert. Or you can use completion commands (see Completion Commands) to complete on an entry from the list of entries in the kill ring or pop up the *Completions* buffer with the candidate entries from which you can choose. After selecting the kill-ring entry, you can optionally edit it in the minibuffer. Finally, type RET to exit the minibuffer and insert the text of the selected kill-ring entry. Like in case of M-y after another yank command, the last-yank pointer is left pointing at the text you just yanked, whether it is one of the previous kills or an entry from the kill-ring that you edited before inserting it. (In the latter case, the edited entry is added to the front of the kill-ring.) So here, too, typing C-y will yank another copy of the text just inserted.
When invoked with a plain prefix argument (C-u M-y) after a command that is not a yank command, M-y leaves the cursor in front of the inserted text, and sets the mark at the end, like C-y does.
Normally, each kill command pushes a new entry onto the kill ring. However, two or more kill commands in a row combine their text into a single entry, so that a single C-y yanks all the text as a unit, just as it was before it was killed.
Thus, if you want to yank text as a unit, you need not kill all of it with one command; you can keep killing line after line, or word after word, until you have killed it all, and you can still get it all back at once.
Commands that kill forward from point add onto the end of the previous killed text. Commands that kill backward from point add text onto the beginning. This way, any sequence of mixed forward and backward kill commands puts all the killed text into one entry without rearrangement. Numeric arguments do not break the sequence of appending kills. For example, suppose the buffer contains this text:
This is a line ∗of sample text.
with point shown by ∗. If you type M-d M-DEL M-d M-DEL, killing alternately forward and backward, you end up with ‘a line of sample’ as one entry in the kill ring, and ‘This is text.’ in the buffer. (Note the double space between ‘is’ and ‘text’, which you can clean up with M-SPC or M-q.)
Another way to kill the same text is to move back two words with M-b M-b, then kill all four words forward with C-u M-d. This produces exactly the same results in the buffer and in the kill ring. M-f M-f C-u M-DEL kills the same text, all going backward; once again, the result is the same. The text in the kill ring entry always has the same order that it had in the buffer before you killed it.
If a kill command is separated from the last kill command by other
commands (not just numeric arguments), it starts a new entry on the
kill ring. But you can force it to combine with the last killed text,
by typing C-M-w (append-next-kill) right beforehand. The
C-M-w tells its following command, if it is a kill command, to
treat the kill as part of the sequence of previous kills. As usual,
the kill is appended to the previous killed text if the command kills
forward, and prepended if the command kills backward. In this way,
you can kill several separated pieces of text and accumulate them to
be yanked back in one place.
A kill command following M-w (kill-ring-save) does not
append to the text that M-w copied into the kill ring.
In most graphical desktop environments, you can transfer data (usually text) between different applications using a system facility called the clipboard. On X, two other similar facilities are available: the primary selection and the secondary selection. When Emacs is run on a graphical display, its kill and yank commands integrate with these facilities, so that you can easily transfer text between Emacs and other graphical applications.
By default, Emacs uses UTF-8 as the coding system for inter-program
text transfers. If you find that the pasted text is not what you
expected, you can specify another coding system by typing C-x
RET x or C-x RET X. You can also request a
different data type by customizing x-select-request-type.
See Coding Systems for Interprocess Communication.
The clipboard is the facility that most graphical applications use for “cutting and pasting”. When the clipboard exists, the kill and yank commands in Emacs make use of it.
When you kill some text with a command such as C-w
(kill-region), or copy it to the kill ring with a command such
as M-w (kill-ring-save), that text is also put in the
clipboard.
When an Emacs kill command puts text in the clipboard, the existing
clipboard contents are normally lost. Optionally, Emacs can save the
existing clipboard contents to the kill ring, preventing you from
losing the old clipboard data. If
save-interprogram-paste-before-kill has been set to a number,
then the data is copied over if it’s smaller (in characters) than
this number. If this variable is any other non-nil value, the
data is always copied over—at the risk of high memory consumption if
that data turns out to be large.
Yank commands, such as C-y (yank), also use the
clipboard. If another application “owns” the clipboard—i.e., if
you cut or copied text there more recently than your last kill command
in Emacs—then Emacs yanks from the clipboard instead of the kill
ring.
Normally, rotating the kill ring with M-y (yank-pop)
does not alter the clipboard. However, if you change
yank-pop-change-selection to t, then M-y saves the
new yank to the clipboard.
To prevent kill and yank commands from accessing the clipboard,
change the variable select-enable-clipboard to nil.
Programs can put other things than plain text on the clipboard. For
instance, a web browser will usually let you choose “Copy Image” on
images, and this image will be put on the clipboard. On capable
platforms, Emacs can yank these objects with the yank-media
command—but only in modes that have support for it. By default, it
auto-selects the preferred media type available in the clipboard but
this can be overridden by giving the prefix argument to the command
(see Yanking Media in The Emacs Lisp Reference Manual).
Many X desktop environments support a feature called the
clipboard manager. If you exit Emacs while it is the current
“owner” of the clipboard data, and there is a clipboard manager
running, Emacs transfers the clipboard data to the clipboard manager
so that it is not lost. In some circumstances, this may cause a delay
when exiting Emacs; if you wish to prevent Emacs from transferring
data to the clipboard manager, change the variable
x-select-enable-clipboard-manager to nil.
Since strings containing NUL bytes are usually truncated when passed through the clipboard, Emacs replaces such characters with “\0” before transferring them to the system’s clipboard.
Prior to Emacs 24, the kill and yank commands used the primary
selection (see Cut and Paste with Other Window Applications), not the clipboard. If you
prefer this behavior, change select-enable-clipboard to
nil, select-enable-primary to t, and
mouse-drag-copy-region to t. In this case, you can use
the following commands to act explicitly on the clipboard:
clipboard-kill-region kills the region and saves it to the
clipboard; clipboard-kill-ring-save copies the region to the
kill ring and saves it to the clipboard; and clipboard-yank
yanks the contents of the clipboard at point.
Under the X Window System, PGTK and Haiku, there exists a primary selection containing the last stretch of text selected in an X application (usually by dragging the mouse). Typically, this text can be inserted into other X applications by mouse-2 clicks. The primary selection is separate from the clipboard. Its contents are more fragile; they are overwritten each time you select text with the mouse, whereas the clipboard is only overwritten by explicit cut or copy commands.
Under X, whenever the region is active (see The Mark and the Region), the text in the region is saved in the primary selection. This applies regardless of whether the region was made by dragging or clicking the mouse (see Mouse Commands for Editing), or by keyboard commands (e.g., by typing C-SPC and moving point; see Setting the Mark).
If you change the variable select-active-regions to
only, Emacs saves only temporarily active regions to the
primary selection, i.e., those made with the mouse or with shift
selection (see Shift Selection). If you change
select-active-regions to nil, Emacs avoids saving active
regions to the primary selection entirely.
To insert the primary selection into an Emacs buffer, click
mouse-2 (mouse-yank-primary) where you want to insert it.
See Mouse Commands for Editing. You can also use the normal Emacs yank command
(C-y) to insert this text if select-enable-primary is set
(see Using the Clipboard).
By default, Emacs keeps the region active even after text is
selected in another program; this is contrary to typical X behavior.
To make Emacs deactivate the region after another program places data
in the primary selection, enable the global minor mode
lost-selection-mode.
MS-Windows provides no primary selection, but Emacs emulates it within a single Emacs session by storing the selected text internally. Therefore, all the features and commands related to the primary selection work on Windows as they do on X, for cutting and pasting within the same session, but not across Emacs sessions or with other applications.
In addition to the primary selection, the X Window System provides a second similar facility known as the secondary selection. Nowadays, few X applications make use of the secondary selection, but you can access it using the following Emacs commands:
Set the secondary selection, with one end at the place where you press
down the button, and the other end at the place where you release it
(mouse-set-secondary). The selected text is highlighted, using
the secondary-selection face, as you drag. The window scrolls
automatically if you drag the mouse off the top or bottom of the
window, just like mouse-set-region (see Mouse Commands for Editing).
This command does not alter the kill ring.
Set one endpoint for the secondary selection
(mouse-start-secondary); use M-mouse-3 to set the other
end and complete the selection. This command cancels any existing
secondary selection, when it starts a new one.
Set the secondary selection (mouse-secondary-save-then-kill),
with one end at the position you click M-mouse-3, and the other
at the position specified previously with M-mouse-1. This also
puts the selected text in the kill ring. A second M-mouse-3 at
the same place kills the text selected by the secondary selection just
made.
Insert the secondary selection where you click, placing point at the
end of the yanked text (mouse-yank-secondary).
Double or triple clicking of M-mouse-1 operates on words and lines, much like mouse-1.
If mouse-yank-at-point is non-nil, M-mouse-2 yanks
at point. Then it does not matter precisely where you click, or even
which of the frame’s windows you click on. See Mouse Commands for Editing.
This user option also effects interactive search: if it is
non-nil, yanking with the mouse anywhere in the frame will add
the text to the search string.
Usually we copy or move text by killing it and yanking it, but there are other convenient methods for copying one block of text in many places, or for copying many scattered blocks of text into one place. Here we describe the commands to accumulate scattered pieces of text into a buffer or into a file.
Append region to the contents of a specified buffer.
Prepend region to the contents of a specified buffer.
Copy region into a specified buffer, deleting that buffer’s old contents.
Insert the contents of a specified buffer into current buffer at point.
Append region to the contents of a specified file, at the end.
To accumulate text into a buffer, use M-x append-to-buffer.
This reads a buffer name, then inserts a copy of the region into the
buffer specified. If you specify a nonexistent buffer,
append-to-buffer creates the buffer. The text is inserted
wherever point is in that buffer. If you have been using the buffer for
editing, the copied text goes into the middle of the text of the buffer,
starting from wherever point happens to be at that moment.
Point in that buffer is left at the end of the copied text, so
successive uses of append-to-buffer accumulate the text in the
specified buffer in the same order as they were copied. Strictly
speaking, append-to-buffer does not always append to the text
already in the buffer—it appends only if point in that buffer is at
the end. However, if append-to-buffer is the only command you
use to alter a buffer, then point is always at the end.
M-x prepend-to-buffer is just like append-to-buffer
except that point in the other buffer is left before the copied text, so
successive uses of this command add text in reverse order. M-x
copy-to-buffer is similar, except that any existing text in the other
buffer is deleted, so the buffer is left containing just the text newly
copied into it.
The command C-x x i (insert-buffer) can be used to
retrieve the accumulated text from another buffer. This prompts for
the name of a buffer, and inserts a copy of all the text in that
buffer into the current buffer at point, leaving point at the
beginning of the inserted text. It also adds the position of the end
of the inserted text to the mark ring, without activating the mark.
See Using Multiple Buffers, for background information on buffers.
Instead of accumulating text in a buffer, you can append text directly into a file with M-x append-to-file. This prompts for a filename, and adds the text of the region to the end of the specified file. The file is changed immediately on disk.
You should use append-to-file only with files that are
not being visited in Emacs. Using it on a file that you are
editing in Emacs would change the file behind Emacs’s back, which
can lead to losing some of your editing.
Another way to move text around is to store it in a register. See Registers.
Rectangle commands operate on rectangular areas of the text: all the characters between a certain pair of columns, in a certain range of lines. Emacs has commands to kill rectangles, yank killed rectangles, clear them out, fill them with blanks or text, or delete them. Rectangle commands are useful with text in multicolumn formats, and for changing text into or out of such formats.
To specify a rectangle for a command to work on, set the mark at one corner and point at the opposite corner. The rectangle thus specified is called the region-rectangle. If point and the mark are in the same column, the region-rectangle is empty. If they are in the same line, the region-rectangle is one line high.
The region-rectangle is controlled in much the same way as the region is controlled. But remember that a given combination of point and mark values can be interpreted either as a region or as a rectangle, depending on the command that uses them.
A rectangular region can also be marked using the mouse: click and drag C-M-mouse-1 from one corner of the rectangle to the opposite.
Kill the text of the region-rectangle, saving its contents as the
last killed rectangle (kill-rectangle).
Save the text of the region-rectangle as the last killed rectangle
(copy-rectangle-as-kill).
Delete the text of the region-rectangle (delete-rectangle).
Yank the last killed rectangle with its upper left corner at point
(yank-rectangle).
Insert blank space to fill the space of the region-rectangle
(open-rectangle). This pushes the previous contents of the
region-rectangle to the right.
Insert line numbers along the left edge of the region-rectangle
(rectangle-number-lines). This pushes the previous contents of
the region-rectangle to the right.
Clear the region-rectangle by replacing all of its contents with spaces
(clear-rectangle).
Delete whitespace in each of the lines on the specified rectangle, starting from the left edge column of the rectangle.
Replace rectangle contents with string on each line
(string-rectangle).
Insert string on each line of the rectangle.
Toggle Rectangle Mark mode (rectangle-mark-mode).
When this mode is active, the region-rectangle is highlighted and can
be shrunk/grown, and the standard kill and yank commands operate on it.
The rectangle operations fall into two classes: commands to erase or insert rectangles, and commands to make blank rectangles.
There are two ways to erase the text in a rectangle: C-x r d
(delete-rectangle) to delete the text outright, or C-x r
k (kill-rectangle) to remove the text and save it as the
last killed rectangle. In both cases, erasing the
region-rectangle is like erasing the specified text on each line of
the rectangle; if there is any following text on the line, it moves
backwards to fill the gap.
Killing a rectangle is not killing in the usual sense; the rectangle is not stored in the kill ring, but in a special place that only records the most recent rectangle killed. This is because yanking a rectangle is so different from yanking linear text that different yank commands have to be used. Yank-popping is not defined for rectangles.
C-x r M-w (copy-rectangle-as-kill) is the equivalent of
M-w for rectangles: it records the rectangle as the last
killed rectangle, without deleting the text from the buffer.
To yank the last killed rectangle, type C-x r y
(yank-rectangle). The rectangle’s first line is inserted at
point, the rectangle’s second line is inserted at the same horizontal
position one line vertically below, and so on. The number of lines
affected is determined by the height of the saved rectangle.
For example, you can convert two single-column lists into a double-column list by killing one of the single-column lists as a rectangle, and then yanking it beside the other list.
You can also copy rectangles into and out of registers with C-x r r r and C-x r i r. See Saving Rectangles in Registers.
There are two commands you can use for making blank rectangles:
C-x r c (clear-rectangle) blanks out existing text in the
region-rectangle, and C-x r o (open-rectangle) inserts a
blank rectangle.
M-x delete-whitespace-rectangle deletes horizontal whitespace starting from a particular column. This applies to each of the lines in the rectangle, and the column is specified by the left edge of the rectangle. The right edge of the rectangle does not make any difference to this command.
The command C-x r N (rectangle-number-lines) inserts
line numbers along the left edge of the region-rectangle. Normally,
the numbering begins from 1 (for the first line of the rectangle).
With a prefix argument, the command prompts for a number to begin
from, and for a format string with which to print the numbers
(see Formatting Strings in The Emacs Lisp Reference
Manual).
The command C-x r t (string-rectangle) replaces the
contents of a region-rectangle with a string on each line. The
string’s width need not be the same as the width of the rectangle. If
the string’s width is less, the text after the rectangle shifts left;
if the string is wider than the rectangle, the text after the
rectangle shifts right.
The command M-x string-insert-rectangle is similar to
string-rectangle, but inserts the string on each line,
shifting the original text to the right.
The command C-x SPC (rectangle-mark-mode) toggles
whether the region-rectangle or the standard region is highlighted
(first activating the region if necessary). When this mode is enabled,
commands that resize the region (C-f, C-n etc.) do
so in a rectangular fashion, and killing and yanking operate on the
rectangle. See Killing and Moving Text. The mode persists only as long as the
region is active.
The region-rectangle works only when the mark is active. In particular, when Transient Mark mode is off (see Disabling Transient Mark Mode), in addition to typing C-x SPC you will need to activate the mark.
Unlike the standard region, the region-rectangle can have its corners extended past the end of buffer, or inside stretches of white space that point normally cannot enter, like in the middle of a TAB character.
When the region is active (see The Mark and the Region) and in rectangle-mark-mode,
C-x C-x runs the command
rectangle-exchange-point-and-mark, which cycles between the
four corners of the region-rectangle. This comes in handy if you want
to modify the dimensions of the region-rectangle before invoking an
operation on the marked text.
The command M-x cua-mode sets up key bindings that are compatible with the Common User Access (CUA) system used in many other applications.
When CUA mode is enabled, the keys C-x, C-c, C-v,
and C-z invoke commands that cut (kill), copy, paste (yank), and
undo respectively. The C-x and C-c keys perform cut and
copy only if the region is active. Otherwise, they still act as
prefix keys, so that standard Emacs commands like C-x C-c still
work. Note that this means the variable mark-even-if-inactive
has no effect for C-x and C-c (see Operating on the Region).
To enter an Emacs command like C-x C-f while the mark is active, use one of the following methods: either hold Shift together with the prefix key, e.g., S-C-x C-f, or quickly type the prefix key twice, e.g., C-x C-x C-f.
To disable the overriding of standard Emacs binding by CUA mode,
while retaining the other features of CUA mode described below, set
the variable cua-enable-cua-keys to nil.
CUA mode by default activates Delete-Selection mode (see Mouse Commands for Editing)
so that typed text replaces the active region. To use CUA without this
behavior, set the variable cua-delete-selection to nil.
CUA mode provides enhanced rectangle support with visible rectangle highlighting. Use C-RET to start a rectangle, extend it using the movement commands, and cut or copy it using C-x or C-c. RET moves the cursor to the next (clockwise) corner of the rectangle, so you can easily expand it in any direction. Normal text you type is inserted to the left or right of each line in the rectangle (on the same side as the cursor).
You can use this rectangle support without activating CUA by calling the
cua-rectangle-mark-mode command. There’s also the standard command
rectangle-mark-mode, see Rectangles.
With CUA you can easily copy text and rectangles into and out of
registers by providing a one-digit numeric prefix to the kill, copy,
and yank commands, e.g., C-1 C-c copies the region into register
1, and C-2 C-v yanks the contents of register 2.
CUA mode also has a global mark feature which allows easy moving and copying of text between buffers. Use C-S-SPC to toggle the global mark on and off. When the global mark is on, all text that you kill or copy is automatically inserted at the global mark, and text you type is inserted at the global mark rather than at the current position.
For example, to copy words from various buffers into a word list in a given buffer, set the global mark in the target buffer, then navigate to each of the words you want in the list, mark it (e.g., with S-M-f), copy it to the list with C-c or M-w, and insert a newline after the word in the target list by pressing RET.