Storm's Free Software Collection

cua.el - CUA mode

CUA-mode is a complete replacement for the pc-select, delete-selection, and s-region packages, with one important improvement: it (almost) transparently allows you to use the C-z, C-x, C-c, and C-v keys as you are accustomed to on systems like Windows.

Release 2 adds integrated rectangle and register support, as well as a global mark feature - all using C-x, C-c and C-v rather than the normal plethora of obscure key sequences! Read on...

You can also use the CUA enhancements without rebinding the C-z, C-x, C-c, and C-v keys if you activate it using (CUA-mode 'emacs).

Release 2.x of CUA-mode currently works with GNU Emacs 20.x and 21.1 only.
You can get the older release 1.7 for GNU emacs here.
Xemacs is supported by this older version (1.3).

As of release 2.4, the file name for CUA-mode has been changed from cua-mode.el to simply cua.el. If you are already using CUA-mode, you may either continue using the file name cua-mode.el, or you must change your .emacs file to specify (require 'cua).


This is the CUA-mode package which provides a complete emulatation of the standard CUA key bindings (Motif/Windows/Mac GUI) for selecting and manipulating the region where S-<movement> is used to highlight & extend the region.

This package allow the C-z, C-x, C-c, and C-v keys to be bound appropriately according to the Motif/Windows GUI, i.e.
Emacs KeyCUA KeyFunction

The tricky part is the handling of the C-x and C-c keys which are normally used as prefix keys for most of emacs' built-in commands.
With CUA-mode they still do!!!

Only when the region is currently active (and highlighted since transient-mark-mode is used), the C-x and C-c keys will work as CUA keys, i.e. cut and copy, but when the region is not active, C-x and C-c works as ordinary emacs prefix keys!

This probably sounds strange and difficult to get used to - but based on my own experience and the feedback from many users of CUA-mode, it actually works very well and users adapt to it instantly - or at least very quickly. So give it a try!
... and in the few cases where you make a mistake and accidentally delete the region - you just undo the mistake (with C-z).

If you really need to perform a command which starts with one of the prefix keys even when the region is active, you have three options:

  • Press the prefix key twice very quickly (within 0.2 seconds),
  • press the prefix key and the following key within 0.2 seconds), or
  • use the SHIFT key with the prefix key, i.e. C-X or C-C

In addition to using the shifted movement keys, you can also use [C-space] to start the region and use unshifted movement keys to extend it. To cancel the region, use [C-space] or [C-g].


Place the cua.el file somewhere on your load path, byte compile it, and insert the following lines in your .emacs file:
  (require 'cua)
  (CUA-mode t)

If you don't want to modify the bindings of C-z C-x C-c C-v, but still want the CUA enhanced functionality for the standard emacs bindings of undo, kill, copy, and yank, use the following lines instead:

  (require 'cua)
  (CUA-mode 'emacs)

New features

With release 2 of the CUA-mode package, the CUA commands have been extended to handle both rectangles and registers in a homogeneous manner, as well as adding the concept of a "global mark" as described below.

CUA rectangle support

Emacs' normal rectangle support is based on interpreting the region between the mark and point as a "virtual rectangle", and using a completely separate set of "rectangle commands" [C-x r ...] on the region to copy, kill, fill a.s.o. the virtual rectangle.

CUA-mode's superior rectangle support is based on using a true visual representation of the selected rectangle. To start a rectangle, use [S-return] and extend it using the normal movement keys (up, down, left, right, home, end, C-home, C-end). Once the rectangle has the desired size, you can cut or copy it using C-x and C-c, and you can subsequently insert it - as a rectangle - using C-v. So the only new command you need to know to work with CUA-mode rectangles is S-return!

Furthermore, CUA-mode's rectangles are not limited to the actual contents of the buffer, so if the cursor is currently at the end of a short line, you can still extend the rectangle to include more columns of longer lines in the same rectangle. Sounds strange? Try it!

You can enable padding for just this rectangle by pressing [M-p]; this works like entering 'picture mode' where the tabs and spaces are automatically converted/inserted to make the rectangle truly rectangular. Or you can do it for all rectangles by setting the CUA-mode-auto-expand-rectangles variable to 'yes.

And there's more: If you want to extend or reduce the size of the rectangle in one of the other corners of the rectangle, just use [return] to move the cursor to the "next" corner. Or you can use the [M-up], [M-down], [M-left], and [M-right] keys to move the entire rectangle overlay (but not the contents) in the given direction.

  [S-return] cancels the rectangle
  [C-space]  activate region bounded by rectangle
If you type a normal (self-inserting) character when the rectangle is active, the character is inserted on the "current side" of every line of the rectangle. The "current side" is the side on which the cursor is currently located. If the rectangle is only 1 column wide, insertion will be performed to the left when the cursor is at the bottom of the rectangle. So, for example, to comment out an entire paragraph like this one, just place the cursor on the first character of the first line, and enter the following:
    [S-return] [down].... [;; ] [S-return]
CUA-mode's rectangle support also includes all the normal rectangle functions with easy access:
[M-a]aligns all words at the left edge of the rectangle
[M-b]fills the rectangle with blanks (tabs and spaces)
[M-c]closes the rectangle by removing all blanks at the left edge of the rectangle
[M-f]fills the rectangle with a single character (prompt)
[M-F]performs text filling on the rectangle
[M-i]increases the first number found on each line of the rectangle by the amount given by the numeric prefix argument (default 1) It recognizes 0x... as hexadecimal numbers
[M-k]kills the rectangle as a normal multi-line text (for paste)
[M-l]downcases the rectangle
[M-m]kills the rectangle as a normal multi-line text (for paste)
[M-n]fills each line of the rectangle with increasing numbers using a supplied format string (prompt)
[M-o]opens the rectangle by moving the highlighted text to the right of the rectangle and filling the rectangle with blanks.
[M-p]toggles rectangle padding, i.e. insert tabs and spaces to make rectangles truly rectangular
[M-r]replaces REGEXP (prompt) by STRING (prompt) in rectangle
[M-R]reverse the lines in the rectangle
[M-s]fills each line of the rectangle with the same STRING (prompt)
[M-t]performs text fill of the rectangle with TEXT (prompt)
[M-u]upcases the rectangle
[M-|]runs shell command on rectangle
[M-']restricts rectangle to lines with CHAR (prompt) at left column
[M-/]restricts rectangle to lines matching REGEXP (prompt)
[C-?]Shows a brief list of the above commands.
scrolls the lines INSIDE the rectangle up and down; lines scrolled outside the top or bottom of the rectangle are lost, but can be recovered using [C-z].

CUA register support

Emacs' standard register support is also based on a separate set of "register commands".

CUA-mode's register support is activated by providing a numeric prefix argument to the C-x, C-c, and C-v commands. For example, to copy the selected region to register 2, enter [M-2 C-c]. Or if you have activated the keypad prefix mode, enter [kp-2 C-c].

And CUA-mode will copy and paste normal region as well as rectangles into the registers, i.e. you use exactly the same command for both.

In addition, the last highlighted text that is deleted (not copied), e.g. by typing text over a highlighted region, is automatically saved in register 0, so you can insert it using [kp-0 C-v].

CUA Global Mark

The final feature provided by CUA-mode is the "global mark", which makes it very easy to copy bits and pieces from the same and other files into the current text. To enable and cancel the global mark, use [S-C-space]. The cursor will blink when the global mark is active. The following commands behave differently when the global mark is set:
<ch> All characters (including returns) you type are inserted at the global mark!
[C-x]If you cut a region or rectangle, it is automatically inserted at the global mark, and the global mark is advanced.
[C-c]If you copy a region or rectangle, it is immediately inserted at the global mark, and the global mark is advanced.
[C-v]Copies a single character to the global mark.
[C-d]Moves (i.e. deletes and inserts) a single character to the global mark.
[backspace]deletes the character before the global mark
[delete]deltes the character after the global mark
[S-C-space]Jumps to and cancels the global mark.
[C-u S-C-space]Cancels the global mark (stays in current buffer).

CUA mode indications

As mentioned above, the cursor will blink when the global mark is active. In addition, you can choose to let CUA-mode use different cursor colors to indicate overwrite mode and read-only buffers. For example, the following setting will use a RED cursor in normal (insertion) mode in read-write buffers, a YELLOW cursor in overwrite mode in read-write buffers, and a GREEN cursor read-only buffers:
 (setq CUA-mode-normal-cursor-color "red")
 (setq CUA-mode-overwrite-cursor-color "yellow")
 (setq CUA-mode-read-only-cursor-color "green")

Additional information

When the region is highlighted, TAB and S-TAB will indent the entire region by the normal tab-width (or the given prefix argument).

C-x C-x (exchange point and mark) no longer activates the mark (i.e. highlights the region). I found that to be confusing since the sequence C-x C-x (exchange once) followed by C-x C-x (change back) would then cut the region! To activate the region in this way, use C-u C-x C-x.

[delete] will delete (not copy) the highlighted region.

The highlighted region is automatically deleted if other text is typed or inserted. The previously highlighted text is saved in register 0 (if CUA-mode-delete-to-register-0 is non-nil).

You may choose to use M-r as a prefix for the register commands instead of C-x r by setting CUA-mode-register-commands-prefix. The original binding of M-r (move-to-window-line) is then moved to M-r M-r.

Normally, when you paste a rectangle using C-v, each line of the rectangle is inserted into the existing lines in the buffer. However, if overwrite-mode is turned on, the lines of the rectangle are inserted as a single block of lines at point.

CUA-mode works in a very homogeneous way via a versatile pre-command-hook (like delsel.el). It does not rebind any of the cursor movement or scrolling keys; instead it puts different CUA properties on each of these commands which the pre-command hook reacts to. This has the added bonus of C-h k key returning the proper binding of key (rather than some obscure function which messes with the mark, as some of the other similar packages do).
It uses the transient-mark-mode to highlight the selected region.
The interpretation of C-x and C-c as either emacs prefix keys or CUA cut/copy keys is handled via emacs' key-translation-map feature.

Utilizing the numeric keypad

You can also bind the keys in the numeric keypad to work as numeric prefix keys using the CUA-keypad-mode function as follows:
  (CUA-keypad-mode 'prefix t)

This function provides a number of different standard bindings for the keypad:

  (CUA-keypad-mode mode &optional numlock decimal)
This sets the keypad bindings (in the function-key-map) according to MODE.
'prefix Command prefix argument, i.e. M-0 .. M-9 and M--
'cursor Bind keypad keys to the cursor movement keys.
'numericPlain numeric, i.e. 0 .. 9 and . (or DECIMAL arg)
'none Removes all bindings for keypad keys in function-key-map.

If the optional second argument NUMLOCK is non-nil, the NumLock On bindings are changed. Otherwise, the NumLock Off binding are changed.

If mode is 'numeric and the optional third argument DECIMAL is non-nil, the decimal key on the keypad is mapped to DECIMAL instead of [.]."


CUA-mode includes code and ideas from several related packages: pc-selection-mode by Michael Staats s-region by Morten Welinder delete-selection-mode by Matthieu Devin

The rectangle handling and display code borrows from the standard GNU emacs rect.el package and the the rect-mark.el package by Rick Sladkey .

Revision History

  • Revision 2.10, 2002-01-08
    Added CUA-mode-remap-cx-shift-only and CUA-mode-highlight-shift-only customization options to make CUA-mode less aggressive when the standard emacs bindings are used, i.e. when the region is started with C-SPC.
    Specifically, if these options are set, the special remapping of C-x and C-c and the use of transient-mark-mode will only be enabled if the region is marked with shifted movement keys.

  • Revision 2.9, 2002-01-04
    Rectangles can now be extended using any command which moves the point, including clicking with mouse-1. If rectangle padding is active, mouse-1 will set extend the rectangle to the exact window position clicked on.
    New CUA-cmd-do-rectangle-padding (H-P) to pad rectangle without turning on padding. Also used to pad rectangle after point has moved is padding is enabled.
    Fixed: The rectangle corners are now updated after padding rectangle.
    Fixed: yanking after a copy rectangle followed by a normal kill would paste the rectangle rather than the killed text.
    Fixed: yank-pop after yanking a rectangle didn't work correctly (it could fail to remove the yanked rectangle, and it would then insert the previous kill-ring element where the mark happened to be set. However, this still only works if undo is enabled in the buffer.
    Fixed: Bind \r rather than RET in keymaps.
    Fixed: Bind \d like backspace in keymaps.
    Added CUA-movement-key function for other packages to use.
    Added support for begendol.el commands.

  • Revision 2.8, 2001-12-09
    The C-x 8 prefix (iso-translation) now works with CUA.

  • Revision 2.7, 2001-10-31
    Handle commands from foreign packages by looking for a delete-selection property of commands without a CUA property.

  • Revision 2.6, 2001-10-15
    Handle kill-ring-save (M-w) as CUA-copy-region command.
    Do not rebind shifted and unshifted movement commands to keys if using emacs-bindings, i.e. (CUA-mode 'emacs).
    (CUA-mode-bindings 'zxcv) binds C-z C-x C-c and C-v.
    (CUA-mode-bindings 'shift) binds (un)shifted movement keys.

  • Revision 2.5, 2001-06-27
    Standard emacs binding for undo, kill, copy, and yank can now be used when activated by (CUA-mode 'emacs) .
    Alternatively, CUA-mode-emacs-bindings can be set prior to activating CUA-mode.
    Fixed: [return] didn't work in mini-buffer when Global Mark is active.

  • Revision 2.4, 2001-05-30
    Changed package location to
    Changed file name from cua-mode.el to cua.el
  • Revision 2.3, 2001-05-03
    Modified standard CUA keybindings:
    - [C-delete] now runs kill-word rather than kill-line.
    - [C-backspace] now runs backward-kill-word.
    - [delete] now runs delete-char.

  • Revision 2.2, 2001-03-20
    Various fixes to rectangle support.

  • Revision 2.1, 2000-11-22
    Major upgrade.
    Added rectangle support, global marker, and registers.