Holymacs

Here's I share my most used configuration files across systems by simply usiung a shared directory.

(if (file-exists-p "~/Dropbox/emacs/")
    (setq bookmark-file "~/Dropbox/emacs/bookmarks"
            eshell-aliases-file "~/Dropbox/emacs/eshell-aliases"
            custom-file "~/.emacs.d/custom.el"
            org-agenda-files '("~/Dropbox/org/")
            org-roam-directory "~/Dropbox/org-roam/"))
(load custom-file 'noerror)

Just press C-h o to get help on those symbols.

• add-file-local-variable (append at bottom of the file) and add-file-local-variable-prop-line (prepend in the first line)
• align-regexp
• auto-mode-alist
• browse-url-of-buffer
• command-switch-alist
• completions-max-height
• completion-auto-help
• compilation-scroll-output
• current-time-string
• format-time-string
• describe-text-properties
• face-remap-add-relative and face-remap-remove-relative to easily modify faces in current buffer
• find-name-dired
• image-crop
• imenu-generic-expression
• json-pretty-print-buffer
• mm-discouraged-alternatives
• org-agenda-include-diary
• org-agenda-custom-commands
• org-archive-subtree-default
• org-babel-load-file
• org-todo-keywords
• pp-eval-expression
• proced
• shr-inhibit-images
• string-match
• C-x @

#+BEGIN_SRC sh :var filename=(buffer-file-name) :exports both
  wc -w $filename
#+END_SRC

Get an element from a vector

;; get a element from vector
(aref ["a" "b" "c"] 0) ; ⇒ "a"
;; get a element from vector
(elt ["a" "b" "c"] 0) ; ⇒ "a"

What's the difference between aref and elt? elt is more general. It works on vector and list. But if you know it's vector, you should use aref, because it's precise and faster.

To find an element

• member
• contains
• seq-find

(seq-find (lambda (val) (= 3 val)) '(1 2 3))

Refs to this SO post try elisp:(completing-read%20%22Prompt:%20%22%20'(i1%20i2%20i3)) and this post; try elisp:(read-from-minibuffer%20%22Prompt:%20%22%20%22initial%22). Take a look at minemacs/demo-function, it can help if you want to write functions with bit more complex interactive prompts.

(defun minemacs/demo-function (url &optional handler)
  "Example function."
  (interactive (list
		  (read-from-minibuffer "URL: ")
		  (completing-read "handler: " '(browse-url-firefox browse-url-chrome))))
   (message (format "url: %s, handler: %s" url handler )))

You can use the wonderful tool regexp-builder. Use string-match to run a regexp and match-string to extract the captures (remember to specify the 2nd arugment as the matched string itself). Example:

(let ((match-data (string-match "\\(\\ca\\{11\\}\\)\$" "https://www.youtube.com/watch?v=JvBfP62HTAM")))
  (match-string 1 "https://www.youtube.com/watch?v=JvBfP62HTAM"))

Here is the syntax used by Emacs for regular expressions. Any character matches itself, except for the list below.

The following characters are special : . * + ? ^ $ \ [

Between brackets [], the following are special : ] - ^

Many characters are special when they follow a backslash – see below.

. any character (but newline)

• previous character or group, repeated 0 or more time
• previous character or group, repeated 1 or more time

? previous character or group, repeated 0 or 1 time ^ start of line $ end of line […] any character between brackets [^..] any character not in the brackets [a-z] any character between a and z \ prevents interpretation of following special char \| or \w word constituent \b word boundary \sc character with c syntax (e.g. \s- for whitespace char) \( \) start\end of group \< \> start\end of word \_< \_> start\end of symbol \` \' start\end of buffer\string \1 string matched by the first group \n string matched by the nth group \{3\} previous character or group, repeated 3 times \{3,\} previous character or group, repeated 3 or more times \{3,6\} previous character or group, repeated 3 to 6 times \= match succeeds if it is located at point *?, +?, and ?? are non-greedy versions of *, +, and ? – see NonGreedyRegexp. Also, \W, \B, and \Sc match any character that does not match \w, \b, and \sc.

Characters are organized by category. Use C-u C-x = to display the category of the character under the cursor.

\ca ascii character \Ca non-ascii character (newline included) \cl latin character \cg greek character Here are some syntax classes that can be used between brackets, e.g. [[:upper:]\|[:digit:]\.].

[:digit:] a digit, same as [0-9] [:alpha:] a letter (an alphabetic character) [:alnum:] a letter or adigit (an alphanumeric character () [:upper:] a letter in uppercase [:space:] a whitespace character, as defined by the syntax table [:xdigit:] an hexadecimal digit [:cntrl:] a control character [:ascii:] an ascii character Syntax classes:

\s- whitespace character \s/ character quote character \sw word constituent \s$ paired delimiter \s_ symbol constituent \s' expression prefix \s. punctuation character \s< comment starter \s( open delimiter character \s> comment ender \s) close delimiter character \s! generic comment delimiter \s" string quote character \s| generic string delimiter \s\ escape character

You can run specified function at specified time and with a specific timeout. Check out the doc for more information.

(run-at-time "11 min" t #'elfeed-update)
(run-at-time "5 hours" t (lambda () (load-theme (seq-random-elt custom-known-themes))))

The list-timers command lists all the currently active timers. There’s only one command available in the buffer displayed: c (timer-list-cancel) that will cancel the timer on the line under point.

(insert (propertize "Red Text" 'font-lock-face '(:foreground "red")))

Code stolen from stackoverflow.

(defun minemacs-clear-buffer ()
  "clear whole buffer add contents to the kill ring"
  (interactive)
  (kill-region (point-min) (point-max)))

(defun minemacs-clear-buffer-permenantly ()
  "clear whole buffer, contents is not added to the kill ring"
  (interactive)
  (delete-region (point-min) (point-max)))

If you'd like to have a smaller font on compialtion buffers

(add-hook 'compilation-mode-hook (lambda () (text-scale-decrease 1)))

Useful function if you want to quick inspect the face under cursor

(defun what-face (pos)
  (interactive "d")
  (let ((face (or (get-char-property pos 'read-face-name)
                  (get-char-property pos 'face))))
    (if face (message "Face: %s" face) (message "No face at %d" pos))))

Get the list of font families (font-family-list); here's the code to set a random font family in the current frame.

(set-face-font 'default (seq-random-elt (font-family-list)))

• request.el

• Results of Evaluation

• 5 ways to get text from an Emacs buffer

  (let ((start (point-min))
  	  (end (point-max)))
    (buffer-substring start end))