Skip to content


Switch branches/tags

Latest commit


Git stats


Failed to load latest commit information.
Latest commit message
Commit time
Aug 11, 2021

License GPL 3 MELPA MELPA Stable


A Collection of Ridiculously Useful eXtensions for Emacs. crux bundles many useful interactive commands to enhance your overall Emacs experience.

Most of the crux commands are related to the editing experience, but there are also a bunch of utility commands that are just very useful to have (e.g. crux-open-with and crux-reopen-as-root).

Origins of crux

Many of the functions in crux started life as blog posts on Emacs Redux, then were included in Emacs Prelude, before finally being extracted to crux. You can see a full list of blog posts on functions in crux on the tags page.


Available on all major package.el community maintained repos - MELPA Stable and MELPA repos.

MELPA Stable is recommended as it has the latest stable version. MELPA has a development snapshot for users who don't mind breakage but don't want to run from a git checkout.

You can install crux using the following command:

M-x package-install [RET] crux [RET]

If the installation doesn't work try refreshing the package list:

M-x package-refresh-contents

Alternatively, you can add the following code to your Emacs config:

(unless (package-installed-p 'crux)
  (package-install 'crux))


crux doesn't setup any keybindings for its commands out-of-the-box. There are several reasons for this:

  • Most users probably won't need all the commands, so it'd be an overkill to define a minor mode consuming a lot of valuable keybindings
  • Many of the optimal keybindings are in the user space anyways (e.g. C-c some-letter)
  • Everyone has their own preferences when it comes to keybindings

Here's the list of some suggested keybindings. Feel free to bind individual commands to whatever keybindings you prefer.

Command Suggested Keybinding(s) Description
crux-open-with C-c o Open the currently visited file with an external program.
crux-smart-kill-line C-k or Super-k First kill to end of line, then kill the whole line.
crux-smart-open-line-above C-S-RET or Super-o Insert an empty line above the current line and indent it properly.
crux-smart-open-line S-RET or M-o Insert an empty line and indent it properly (as in most IDEs).
crux-cleanup-buffer-or-region C-c n Fix indentation in buffer and strip whitespace.
crux-recentf-find-file C-c f or Super-r Open recently visited file.
crux-recentf-find-directory C-c F Open recently visited directory.
crux-view-url C-c u Open a new buffer containing the contents of URL.
crux-eval-and-replace C-c e Eval a bit of Emacs Lisp code and replace it with its result.
crux-transpose-windows C-x 4 t Transpose the buffers between two windows.
crux-delete-file-and-buffer C-c D Delete current file and buffer.
crux-copy-file-preserve-attributes C-c c Copy current file with file attributes preserved
crux-duplicate-current-line-or-region C-c d Duplicate the current line (or region).
crux-duplicate-and-comment-current-line-or-region C-c M-d Duplicate and comment the current line (or region).
crux-rename-file-and-buffer C-c r Rename the current buffer and its visiting file if any.
crux-visit-term-buffer C-c t Open a terminal emulator (ansi-term).
crux-kill-other-buffers C-c k Kill all open buffers except the one you're currently in.
crux-indent-defun C-M z Indent the definition at point.
crux-indent-rigidly-and-copy-to-clipboard C-c TAB Indent and copy region to clipboard
crux-find-user-init-file C-c I Open user's init file.
crux-find-user-custom-file C-c , Open user's custom file.
crux-find-shell-init-file C-c S Open shell's init file.
crux-top-join-line Super-j or C-^ Join lines
crux-kill-whole-line Super-k Kill whole line
crux-kill-line-backwards C-Backspace Kill line backwards
crux-kill-and-join-forward C-S-Backspace or C-k If at end of line, join with following; otherwise kill line.
crux-kill-buffer-truename C-c P Kill absolute path of file visited in current buffer.
crux-ispell-word-then-abbrev C-c i Fix word using ispell and then save to abbrev.
crux-upcase-region C-x C-u upcase-region when transient-mark-mode is on and region is active.
crux-downcase-region C-x C-l downcase-region when transient-mark-mode is on and region is active.
crux-capitalize-region C-x M-c capitalize-region when transient-mark-mode is on and region is active.
crux-other-window-or-switch-buffer M-o Select other window, or switch to most recent buffer if only one windows.

Here's how you'd bind some of the commands to keycombos:

(global-set-key [remap move-beginning-of-line] #'crux-move-beginning-of-line)
(global-set-key (kbd "C-c o") #'crux-open-with)
(global-set-key [(shift return)] #'crux-smart-open-line)
(global-set-key (kbd "s-r") #'crux-recentf-find-file)
(global-set-key (kbd "C-<backspace>") #'crux-kill-line-backwards)
(global-set-key [remap kill-whole-line] #'crux-kill-whole-line)

For crux-ispell-word-then-abbrev to be most effective you'll also need to add this to your config:

(setq save-abbrevs 'silently)
(setq-default abbrev-mode t)

Using the bundled advices

crux ships with some handy advises that can enhance the operation of existing commands.


You can use crux-with-region-or-buffer to make a command acting normally on a region to operate on the entire buffer in the absence of a region. Here are a few examples you can stuff in your config:

(crux-with-region-or-buffer indent-region)
(crux-with-region-or-buffer untabify)


Likewise, you can use crux-with-region-or-line to make a command alternately act on the current line if the mark is not active:

(crux-with-region-or-line comment-or-uncomment-region)


Sometimes you might want to act on the point until the end of the current line, rather than the whole line, in the absence of a region:

(crux-with-region-or-point-to-eol kill-ring-save)

Minor modes


Crux provides a crux-reopen-as-root command for reopening a file as root. This global minor mode changes find-file so all root files are automatically opened as root.


Copyright © 2015-2021 Bozhidar Batsov and contributors.

Distributed under the GNU General Public License; type C-h C-c to view it.