1 Emacs CheatSheet

• PDF Link: cheatsheet-emacs-A4.pdf, Category: languages
• Blog URL: https://cheatsheet.dennyzhang.com/cheatsheet-emacs-A4
• Related posts: Vim CheatSheet, #denny-cheatsheets

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 _____________________________________________
|                                             |
|          Sequence                           |
|  ______   ________________________________  |
| |      | |                                | |
| | List | |             Array              | |
| |      | |    ________       ________     | |
| |______| |   |        |     |        |    | |
|          |   | Vector |     | String |    | |
|          |   |________|     |________|    | |
|          |  ____________   _____________  | |
|          | |            | |             | | |
|          | | Char-table | | Bool-vector | | |
|          | |____________| |_____________| | |
|          |________________________________| |
|_____________________________________________|

1.1 Features

1.1.1 View In Emacs

Name	Comment
Move forward across one balanced expression	forward-sexp C-M-f
Move backward across one balanced expression	backward-sexp C-M-b

1.1.2 Org-mode export Latex

Name	Comment
Make page size bigger	#+LATEX_HEADER: \usepackage[margin=0.5in]{geometry} Link: stackexchange
Change document class	#+LaTeX_CLASS_OPTIONS: [a4paper] Link: stackexchange
Add the date of today	#+LATEX_HEADER: \rhead{Updated: \today} Link: stackexchange
Add page number with total pages	#+LATEX_HEADER: \rfoot{\thepage\ of \pageref{LastPage}}

1.1.3 Buffer Operations

Name	Comment
Move to top	(goto-char (point-min))
Replace string by regexp	buffer-replace.el
Delete region	(delete-region start-pos end-pos)
Buffer string with plain text	(buffer-substring-no-properties start-pos end-pos)
	(get-buffer-create BUFFER-OR-NAME)
	(current-buffer)
	(set-buffer BUFFER-OR-NAME)
	(kill-buffer)
	(set-buffer-modified-p nil)

1.1.4 GNUS - Mail In Emacs

Name	Comment
Create delayed email	gnus-delay-article C-c C-j
Save mail’s attachment	gnus-summary-save-parts
Forward mail	gnus-summary-mail-forward
Send gnus drafts	gnus-draft-send-message
Send all the sendable drafts	gnus-draft-send-all-messages
Add attachment	mml-attach-file(C-c C-m f)
Create group	gnus-group-make-group (G m)

1.1.5 Table in Org-mode

#+NAME: supplies
| Date       | Category         | Amount |
|------------+------------------+--------|
| 2014/01/14 | Supplies         |  43.97 |
| 2014/02/15 | Supplies         |  56.48 |
| 2014/02/11 | Book             |  17.99 |
| 2014/06/10 | Kinesis Keyboard | 289.16 |
| 2014/08/23 | Printer          |  99.96 |
| 2014/08/30 | Supplies         |  58.26 |
| 2014/08/22 | Books            |  18.99 |
| 2014/08/25 | Books            |   7.50 |
| 2014/09/15 | Books            |  21.49 |
| 2014/12/31 | Toner Service    | :=24.95*4 |
|------------+------------------+--------|
|            | Total:           |        |
#+TBLFM: @>$3=vsum(@2..@-1);%.2f

1.2 Data Structures

1.2.1 Debug

Name	Comment
Debug a function	edebug-defun
Change function via advice	defadvice ;; Super inspiring feature!
Set default value	(setq-default indent-tabs-mode nil)

1.2.2 String

Name	Comment
string1 contains string2	(string-match ".*README.org" buffer-file-truename)
Replace by regexp	(setq ret (replace-regexp-in-string "<hr/>" "" ret))
Format string	(format "%s/%s" mywordpress-server-url blog-uri)
String replace	(replace-string from-string to-string &optional start end)
Replace by regexp	(replace-regexp REGEXP TO-STRING &optional DELIMITED START END)
replace-match	(while (search-forward-regexp "myRegexPattern" nil t) (replace-match "myRepStr"))
The second captured string	(match-string 2)
Get the position of the 2nd captured string	(match-beginning 2) (match-end 2)
List matched count	(setq myStr (replace-regexp-in-string "myRegex1" "myRep1" myStr)) (count-matches "\n")
Grab the start and end positions of a word	(setq myBoundaries (bounds-of-thing-at-point 'word))
	(setq myStr (buffer-substring myStartPos myEndPos))
	(setq myStr (buffer-substring-no-properties myStartPos myEndPos))

1.2.3 Regexp

Name	Comment
Regexp In Emacs	regexp-string-match.el
Change a given string using regex	(replace-regexp-in-string "^ +" "" url)
Seach regexp in some string	(string-match myRegex myStr)
Get captured match	(match-string 1 myStr)
Escape special characters	(regexp-quote "^")
	(regexp-opt '=("hello" "world"))=

1.2.4 Intger

Name	Comment
String to int	(string-to-number STRING &optional BASE)
Check whether it’s int	(integerp 23)
decimal to hex	(format "%x" 10)
hex to decimal	(format "%d" #xa)

1.2.5 Array & List

Name	Comment
Get the first element	(car mylist)
Get the nth element	(nth n mylist)
Get the last element	(car (last mylist))
Get the 2nd to the last elements	(cdr mylist)
Get the nth to the last elements	(nthcdr n mylist)
Similar to (car (car value))	(caar value)
Similar to (cdr (car value))	(cdar value)
Return the cdr of the cdr of X.	(cddr X)

1.2.6 Array & List - More

Name	Comment
Create a list	(defvar my-list (list "item1, item2"))
Add item to list	(add-to-list 'my-list "item3")
Head of a list	(car '(a b c))
Tail of a list	(cdr '(a b c))
Loop a list	(dolist (item my-list) (message item))
Concat two lists	(nconc '("a" "b" "c") '("d" "e" "f")) link
Return a newly created list	(list x)
Append x to the head of a list	(cons x mylist)
Append without duplication	(add-to-list 'auto-mode-alist '("\\.gp$" . gnuplot-mode))
Add ELEMENT if missing	(add-to-list LIST-VAR ELEMENT &optional APPEND COMPARE-FN)

1.2.7 Position

Name	Comment
Return character at position	(char-after (point))
Return character preceding position	(char-before (point))
	(setq myStr (thing-at-point 'word))
	(setq myStr (thing-at-point 'symbol))
	(setq myStr (thing-at-point 'line))

1.2.8 Insert text

Name	Comment
Insert string	(insert "hello world")
	(insert-buffer-substring buffer &optional start end)
	(insert-buffer-substring-no-properties buffer &optional start end)
	(insert-file-contents myPath)
	(insert-file-contents-literally filename &optional visit beg end replace)

1.2.9 Delete text

Name	Comment
	(delete-char 9)
	(delete-region myStartPos myEndPos)
	(erase-buffer)
	(upcase obj)
	(upcase-word n)
	(upcase-region beg end)
	(upcase-initials obj)
	(upcase-initials-region beg end)
	(capitalize obj)
	(capitalize-word n)
	(capitalize-region beg end)
	(downcase)
	(downcase-word n)
	(downcase-region beg end)

1.2.10 DateTime

Name	Comment
Convert time to string	(format-time-string "<%Y-%m-%d %H:%M UTC +8>" (current-time))
Get current time	(current-time)
Add some offset for a time	(time-add time (seconds-to-time seconds))
Subtract two time values	(time-subtract after-init-time before-init-time)
Get second count	(float-time (time-subtract after-init-time before-init-time))
Return date as a list (mm/dd/yyyy)	calendar-current-date
	(calendar-extract-month date)
m1 will be changed	(calendar-increment-month m1 y1 -1)
	(calendar-date-compare '((12 27 2012)) '((12 26 2012)))
	(calendar-holiday-list)

1.2.11 Hook

Name	Comment
Add hook	(add-hook 'myhook '(lambda () (insert "fun1 was called ")))
Run each hook in myhook	(run-hooks 'myhook)

1.2.12 Files

Name	Comment
Open file	(find-file html-file)
Save file	(write-file html-file nil)
Get short filename	(file-name-nondirectory somefilename)
Get the directory name from filename	(file-name-directory FILENAME)
Check file/directories existence	(file-exists-p bfilename)
Insert contents of file FILENAME after point	(insert-file-contents somefilename)
Return FILENAME’s final “extension”	(file-name-extension "test.erl")
Return FILENAME sans final “extension”	(file-name-sans-extension "test.erl")
Return a list of names of files in DIRECTORY	(directory-files DIRECTORY &optional FULL MATCH NOSORT)
Insert contents of file FILENAME after point	(insert-file-contents FILENAME &optional VISIT BEG END REPLACE)
Confirm directory exists	(file-directory-p FILENAME)
Create directory	(make-directory "~/.emacs.d/autosaves/" t)
Find files by name	(find-dired "../" "-name defined.hrl")
read file content into a string	(setq dddstring (with-temp-buffer (insert-file-contents "dd.txt")=(buffer-string)))

1.3 More Resources

License: Code is licensed under MIT License.