emacs.md

title	date	icon	background	tags	categories	intro
Emacs	2020-12-17 08:21:49 -0800	icon-emacs	bg-[#7752a9]	editor text shortcut	Toolkit	[Emacs](https://www.gnu.org/software/emacs) is the extensible, customizable, self-documenting real time display text editor. This reference was made for Emacs 27.

Getting started {.cols-3}

Starting Emacs

To enter Emacs, just type its name:

$ emacs

---

-	-
C-z	Suspend Emacs
C-x C-c	Exit Emacs permanently
{.shortcuts}

Global Description {.secondary}

-	-
C-<key>	Means hold the control, and press <key>
M-<key>	Means press the Esc once, and press <key>
{.shortcuts}

NOTICE: This cheatsheet follows the above rules.

Motion {.row-span-2}

Backward	Forward	Entity to move over
C-b	C-f	Haracter
M-b	M-f	Word
C-p	C-n	Line
C-a	C-e	Line beginning (or end)
M-a	M-e	Sentence
M-{	M-}	Paragraph
C-x [	C-x ]	Page
C-M-b	C-M-f	Sexp
C-M-a	C-M-e	Function
M-<	M->	Buffer beginning (or end)
{.shortcuts .show-header}

Case Change

-	-
M-u	Uppercase word
M-l	Lowercase word
M-c	Capitalize word
C-x C-u	Uppercase region
C-x C-l	Lowercase region
{.shortcuts}

Files

-	-
C-x C-f	Read a file into Emacs
C-x C-s	Save a file back to disk
C-x s	Save all files
C-x i	Insert contents of another file into this buffer
C-x C-v	Replace this file with your file
C-x C-w	Write buffer to a specified file
C-x C-q	Toggle read-only status of buffer
{.shortcuts}

Error Recovery

-	-
C-g	Abort partially typed or executing command
M-x recover-session	Recover files lost by a system crash
C-x u C-_ C-/	Undo an unwanted change
M-x revert-buffer	Restore a buffer to its original contents
C-l	Redraw garbaged screen
{.shortcuts}

Transposing {.row-span-2}

-	-
C-t	Transpose characters
M-t	Transpose words
C-x C-t	Transpose lines
C-M-t	Transpose sexps
{.shortcuts}

Scroll

-	-
C-v	Scroll to next screen
M-v	Scroll to previous screen
C-x <	Scroll left
C-x >	Scroll right
C-l	Scroll current line to center, top, bottom
{.shortcuts}

Goto

-	-
M-g g	Goto line
M-g c	Goto char
M-m	Back to indentation
{.shortcuts}

Marking

-	-
C-@ C-SPC	Uet mark here
C-x C-x	Exchange point and mark
M-@	Set mark arg words away
M-h	Mark paragraph
C-x C-p	Mark page
C-M-@	Mark sexp
C-M-h	Mark function
C-x h	Mark entire buffer
{.shortcuts}

Killing and Deleting {.row-span-2}

Backward	Forward	Entity to kill
DEL	C-d	Character (delete)
M-DEL	M-d	Word
M-0 C-k	C-k	Line (to end of)
C-x DEL	M-k	Sentence
M-- C-M-k	C-M-k	Sexp
{.shortcuts .show-header}

Killing

-	-
C-W	Kill region C-w
M-w	Copy region to kill ring
M-z char	Kill through next occurrence of char
C-y	Yank back last thing killed
M-y	Replace last yank with previous kill
{.shortcuts}

Getting Help

-	-
C-x 1	Remove help window
C-M-v	Scroll help window
C-h a	Apropos: show commands matching a string
C-h k	Describe the function a key runs
C-h f	Describe a function
C-h m	Get mode-specific information
{.shortcuts}

The help system is simple. Type C-h (or F1) and follow the directions. If you are a first-time user, type C-h t for a tutorial.

Multiple Windows {.col-span-2}

When two commands are shown, the second is a similar command for a frame instead of a window. | - | - | - | |---------------|-----------|-------------------------------| | C-x 5 1 | C-x 1 | Delete all other windows | | C-x 5 2 | C-x 2 | Split window, above and below | | C-x 5 0 | C-x 0 | Delete this window |

| C-x 3 || Split window, side by side | | C-M-v || Scroll other window |

| C-x 5 o | C-x o | Switch cursor to another window | | C-x 5 b | C-x 4 b | Select buffer in other window | | C-x 5 C-o | C-x 4 C-o | Display buffer in other window | | C-x 5 f | C-x 4 f | Find file in other window | | C-x 5 r | C-x 4 r | Find file read-only in other window | | C-x 5 d | C-x 4 d | Run Dired in other window | | C-x 5 . | C-x 4 . | Find tag in other window |

| C-x ^ || Grow window taller | | C-x { || Shrink window narrower | | C-x } || Grow window wider | {.shortcuts}

Formatting

-	-
TAB	Indent current line (mode-dependent)
C-M-\	Indent region (mode-dependent)
C-M-q	Indent sexp (mode-dependent)
C-x TAB	Indent region rigidly arg columns
M-;	Indent for comment
C-o	Insert newline after point
C-M-o	Move rest of line vertically down
C-x C-o	Delete blank lines around point
M-^	Join line with previous (with arg, next)
M-\	Delete all white space around point
M-SPC	Put exactly one space at point
M-q	Fill paragraph
C-x f	Set fill column to arg
C-x .	Set prefix each line starts with
M-o	Set face
{.shortcuts}

Info {.row-span-2}

-	-
C-h i	Enter the Info documentation reader
C-h S	Find specified function or variable in Info
{.shortcuts}

Moving within a node

-	-
SPC	Scroll forward
DEL	Scroll reverse
b	Beginning of node
{.shortcuts}

Moving between nodes

-	-
n	Next node
p	Previous node
u	Move up
m	Select menu item by name
n	Select nth menu item by number (1–9)
f	Follow cross reference (return with l)
l	Return to last node you saw
d	Return to directory node
t	Go to top node of Info file
g	Go to any node by name
{.shortcuts}

Other

-	-
h	Run Info tutorial
i	Look up a subject in the indices
s	Search nodes for regexp
q	Quit Info
{.shortcuts}

Minibuffer

The following keys are defined in the minibuffer. | - | - | |-------|-----------------------------------------| | TAB | Complete as much as possible | | SPC | Complete up to one word | | RET | Complete and execute | | ? | Show possible completions | | M-p | Fetch previous minibuffer input | | M-n | Fetch later minibuffer input or default | | M-r | Regexp search backward through history | | M-s | Regexp search forward through history | | C-g | Abort command | {.shortcuts}

Type C-x ESC ESC to edit and repeat the last command that used the minibuffer. Type F10 to activate menu bar items on text terminals.

Tags

-	-
M-.	Find a tag (a definition)
C-u M-.	Find next occurrence of tag
M-x visit-tags-table	Specify a new tags file
M-x tags-search	Regexp search on all files in tags table
M-x tags-query-replace	Run query-replace on all the files
M-,	Continue last tags search or query-replace
{.shortcuts}

Rectangles

-	-
C-x r r	Copy rectangle to register
C-x r k	Kill rectangle
C-x r y	Yank rectangle
C-x r o	Open rectangle, shifting text right
C-x r c	Blank out rectangle
C-x r t	Prefix each line with a string
{.shortcuts}

Keyboard Macros

-	-
C-x (	Start defining a keyboard macro
C-x )	End keyboard macro definition
C-x e	Execute last-defined keyboard macro
C-u C-x (	Append to last keyboard macro
M-x name-last-kbd-macro	Name last keyboard macro
M-x insert-kbd-macro	Insert Lisp definition in buffer
{.shortcuts}

Buffers

-	-
C-x b	Select another buffer
C-x C-b	List all buffers
C-x k	Kill a buffer
{.shortcuts}

Emacs Search{.cols-3}

Regex (common) {.row-span-2}

-	-
. (dot)	Any single character except a newline
*	Zero or more repeats
+	One or more repeats
?	Zero or one repeat
\	Quote special characters
\c	Quote regular expression special character c
|	Alternative (“or”)
\(...\)	Grouping
\(:?...\)	Shy grouping
\(:NUM...\)	Explicit numbered grouping
\n	Same text as nth group
\b	At word break
\B	Not at word break

Regex (entry)

Start	End	Entity
^	$	Line
\<	\>	Word
\_<	\_>	Symbol
\‘	\’	Buffer
{.show-header}

Regex (conflict)

These	Others	class
[...]	[^...]	Explicit set
\w	\W	Word-syntax character
\sc	\Sc	Character with syntax c
\cc	\Cc	Character with category c
{.show-header}

Incremental Search

-	-
C-s	Search forward
C-r	Search backward
C-M-s	Regular expression search
C-M-r	Reverse regular expression search
M-p	Select previous search string
M-n	Select next later search string
RET	Exit incremental search
DEL	Undo effect of last character
C-g	Abort current search
{.shortcuts}

Use C-s or C-r again to repeat the search in either direction. If Emacs is still searching, C-g cancels only the part not matched.

Query Replace

-	-
M-%	Interactively replace a text string
M-x regexp	Using regular expressions
SPC / y	Replace this one, go on to next
,	Replace this one, don’t move
DEL / n	Skip to next without replacing
!	Replace all remaining matches
^	Back up to the previous match
RET	Exit query-replace
C-r	Enter recursive edit (C-M-c to exit)
{.shortcuts}

Misc {.cols-3}

Shells

-	-
M-!	Execute a shell command
M-&	Execute a shell command asynchronously
M-	Run a shell command on the region
C-u M-	Filter region through a shell command
M-x shell	Start a shell in window shell
{.shortcuts}

International Character Sets {.col-span-2}

-	-
C-x RET l	specify principal language
M-x list-input-methods	show all input methods
C-\	enable or disable input method
C-x RET c	set coding system for next command
M-x list-coding-systems	show all coding systems
M-x prefer-coding-system	choose preferred coding system
{.shortcuts}

Registers

-	-
C-x r s	Save region in register
C-x r i	Insert register contents into buffer
C-x r SPC	Save value of point in register
C-x r j	Jump to point saved in register
{.shortcuts}

Miscellaneous

-	-
C-u num	Numeric argument
M--	Negative argument
C-q char	Quoted insert
{.shortcuts}

Commands Dealing with Emacs Lisp

-	-
C-x C-e	Eval sexp before point
C-M-x	Eval current defun
M-x eval-region	Eval region
M-:	Read and eval minibuffer
M-x load-library	Load a Lisp library from load-path
{.shortcuts}

Simple Customization

-	-
M-x customize	customize variables and faces

Making global key bindings in Emacs Lisp:

(global-set-key (kbd "C-c g") ’search-forward)
(global-set-key (kbd "M-#") ’query-replace-regexp)

Abbrevs

-	-
C-x a g	Add global abbrev
C-x a l	Add mode-local abbrev
C-x a i g	Add global expansion for this abbrev
C-x a i l	Add mode-local expansion for this abbrev
C-x a e	Explicitly expand abbrev
M-/	Expand previous word dynamically
{.shortcuts}

Spelling Check

-	-
M-$	Check spelling of current word
M-x ispell-region	Check spelling of all words in region
M-x ispell-buffer	Check spelling of entire buffer
M-x flyspell-mode	Toggle on-the-fly spell checking
{.shortcuts}

Writing Commands {.col-span-2}

Syntax

(defun command-name (args)
"documentation" (interactive "template")
body)

Example

(defun this-line-to-top-of-window (line)
    "Reposition current line to top of window.
With prefix argument LINE, put point on LINE."
    (interactive "P")
    (recenter (if (null line)
                  0
              (prefix-numeric-value line))))

The interactive spec says how to read arguments interactively. Type C-h f interactive RET for more details.