17 emacs snippets

emacs calendar functions

Open the calendar:

M-x calendar

(You can close the calendar with q, which invokes (calendar-exit).

Movement:

  • C-f or arrow-right is (calendar-forward-day) and C-b or arrow-left is (calendar-backward-day).
  • C-n or arrow-down is (calendar-forward-week) and C-p or arrow-up is (calendar-backward-week).
  • M-} or > is (calendar-forward-month) and M-{ or < is (calendar-backward-month)
  • C-x ] is (calendar-forward-year) and C-x [ is (calendar-backward-year)
  • Use the M-<n> prefix to move a multiple of the above. E.g. M-90 C-f (or M-90 <right-arrow>) moves forward 90 days. (In calendar mode, the meta key is optional, simply 90 <right-arrow> will move forward 90 days, 16 <down-arrow> will move forward 16 weeks, etc.)
  • o will let you interactively select a date.
  • . will return to today

Other:

  • (Right-click on the calendar will generally open up a context-menu about these.)
  • p d is (calendar-print-day-of-year)
  • TypeC-<space>, move to another date and type M-= to invoke (calendar-count-days-region) (show the number of days between the dates (including the endpoints).
  • Type H m or H y to generate an html-format calendar (month and year, respectively). (t <something> generates a number of interesting calendars in TeX, if you are so inclined.)
  • Type h to see known holidays for the selected date, or a to see all holidays for the three month period that is displayed. Use M-x list-holidays for even more. Use M to see a list of lunar phases. Use S to see sunrise/sunset information.

Also see the emacs manual.

Published 15 Apr 2013
Tagged emacs.

 

emacs cursor movement shortcuts

  • M-g g <N> or M-g M-g <N> -- go to line (goto-line)
  • M-g c <N> -- go to character (goto-char)
  • M-g <TAB> <N> -- go to column in the current line

  • M-< -- beginning-of-buffer

  • M-> -- end-of-buffer

  • C-a or <home> -- move-beginning-of-line

  • C-e or <end> -- move-end-of-line

  • C-f or <right> -- forward one char (forward-char) or right one char (right-char). (Note right-char moves backward when editing right-to-left text.)

  • M-f or M-<right> or C-<right> -- forward one word (forward-word) or right one word (right-word).
  • C-b or <left> -- backward one char (backward-char) or left one char (left-char). (Note left-char moves forward when editing right-to-left text.)
  • M-b or M-<left> or C-<left> -- back one word (backward-word) or left one word (left-word).

  • C-n or <down> -- down one line (next-line)

  • C-v or <PageDown> -- down one page (scroll-up-command)
  • C-p or <up> -- up one line (previous-line)
  • M-v or <PageUp> -- up one page (scroll-down-command)

  • C-x C-n -- set current column as "goal" column for up/down movement

  • C-u C-x C-n -- cancel current goal column
Published 15 Mar 2013
Tagged emacs and cheatsheet.

 

Searching in Emacs

  • C-s / C-r -- search / search backward in current buffer
  • M-s o / M-x occur / M-x ioccur -- list lines in current buffer matching regexp
  • M-x rgrep -- recursive grep (find in files)
Published 23 Mar 2013
Tagged emacs and cheatsheet.

 

C-x C-x to toggle between positions

For example: Use C-s foo to search for something. Maybe use C-s again to step thru. Now use C-x C-x to flip back to the point where you started (and C-x C-x again to return).

Published 23 Mar 2013
Tagged emacs.

 

Change font size in emacs

To change the font size in the current buffer:

  • C-x C-+ - increase font size

  • C-x C-- - decrease font size

Follow either with +, - or 0 for continued adjustment.

To change the font size in all buffers:

(set-face-attribute 'default nil :height 120) ;; where `height` is 10x point size
Published 23 Mar 2013
Tagged emacs and elisp.

 

Use M-y to yank (paste) into the emacs i-search prompt

C-s M-y
Published 21 Mar 2013
Tagged emacs.

 

Change Text Case in Emacs

To change the letter case in Emacs:

  • M-u - (upcase-word) - will convert following word to UPPER case (or the rest of the current word).

  • M-l - (downcase-word) - will convert following word to lower case (or the rest of the current word).

  • M-c - (capitalize-word) - will Capitalize the following word (or the rest of the current word).

For example, consider the text The quick brown fox jumped.

If you position the cursor on the q (fifth column), then M-u changes quick to QUICK, M-c changes quick to Quick, etc.

If you position the cursor on the u (sixth column), then M-u changes quick to qUICK, M-c changes quick to qUick, etc.

One could probably write an elisp function based on (capitalize-word) and some heuristics or dictionary look-ups to create a true title case function (e.g., not capitalize a, an, the in the middle of a phrase), but M-c is a quick and easy approximation.

Also, note that there is a version of upcase and downcase that work on the selection (region) instead of the next word.

  • C-x C-u - (upcase-region)

  • C-x C-l - (downcase-region)

Of course, if you're using "CUA Keys", you can't easily type C-x without invoking "cut".

Published 25 Mar 2013
Tagged emacs.

 

Working with R in emacs

1) Install R.

2) Install ESS:

sudo aptitude install ess=12.09-1

3) Require ess-site:

(add-to-list 'load-path "/usr/share/emacs/site-lisp/")
(require 'ess-site)

4) Load R within emacs via M-x R.

Published 26 Mar 2013
Tagged emacs, r-lang and elisp.

 

Default fonts with emacsclient/emacs --daemon

I've been using set-default-font in my .emacs file to configure emacs to use my favorite programming font.

(set-default-font "Droid Sans Mono Slashed-10") ;;; set default font

I use emacs --daemon to keep an instance of emacs running as a background process on my development machine so that I can run emacsclient to call up an emacs window (frame) instantaneously (and keep the same session running even after a close the emacs frame).

Suddenly (after an aptitude safe-upgrade, I think, but I'm not sure what triggered this change), emacs frames that are created by emacsclient connecting to the emacs --daemon instance no longer used my default font when initially opened. The default font worked properly for stand-alone emacs instances (opened with emacs), and for emacsclient, executing (set-default-font) after startup worked fine, but it no longer worked automatically.

To fix this, I had to set up a default-frame-alist, which I believe defines commands to execute whenever a new frame is opened.

(set-default-font "Droid Sans Mono Slashed-10") ;;; set default font
(setq default-frame-alist '((font . "Droid Sans Mono Slashed-10"))) ;;; set default font for emacs --daemon / emacsclient

By the way, I also discovered the describe-font elisp function while trying to diagnose this issue.

(describe-font "Droid Sans Mono Slashed-10")
;; or M-x describe-font <RETURN> Droid Sans Mono Slashed-10 <RETURN>

which opens a *Help* buffer containing:

name (opened by): -unknown-Droid Sans Mono Slashed-normal-normal-normal-*-13-*-*-*-m-0-iso10646-1
       full name: Droid Sans Mono Slashed:pixelsize=13:foundry=unknown:weight=normal:slant=normal:width=normal:spacing=100:scalable=true
            size: 13
          height: 17
 baseline-offset:  0
relative-compose:  0
Published 11 May 2013
Tagged emacs and elisp.

 

various emacs shortcuts

  • In org-mode, <s[tab] inserts a BEGIN_SRC/END_SRC block. (Think "insert source".)
  • Bookmarks
    • C-x r b - jump to bookmark
    • C-x r m - create (make) bookmark
  • M-o M-s / M-o M-S - center line / center paragraph
  • M-<Home>, M-<Page Up>, etc. - move in other window/frame (without losing focus on the current window/frame)
  • cursor movement

    • C-a / C-e - beginning of line / end of line
    • M-a / M-e - beginning of sentence / end of sentence
    • C-b / C-f - backward one character / forward one character
    • C-p / C-n - previous line / next line
  • C-l - recenter top/bottom

  • C-j - newline and indent
  • C-c h - hide lines matching
  • C-h e - show echo area messages
Published 12 May 2013

 

Numbering lines in emacs

A few ways to add line numbers in emacs:

  • M-x linum-mode <RET> will annotate the buffer with line numbers. (These numbers are decoration, in the "fringe" rather than part of the buffer text.) Also see Linum Plus.

  • C-x r N will insert line numbers into the selected region. (These numbers are content, they are added to the text of the buffer.)

  • M-x line-number-mode <RET> show the line number of the current line in the modeline.

  • C-x l will report (in the minibuffer) the total number of lines in the current buffer as well as the number of lines before and after the cursor

  • M-x what-line <RET> will report (in the minibuffer) the current line number

Also see emacswiki.org/LineNumbers.

Published 13 May 2013
Tagged emacs.

 

Simple emacs mode for .gitignore files.

Through the power of generic-mode, adding the following lines to your .emacs file will add syntax-coloring support for .gitignore, .svnignore, etc. files. And by "syntax-coloring" I mean that lines that start with a # will be marked as comments.

(require 'generic-x)
(add-to-list 'auto-mode-alist '("\\..*ignore$" . hosts-generic-mode))

Actually, any text after an un-escaped # will be marked as a comment, which isn't the way Git and SVN interpret those files. (TODO: it would be pretty simple to add a dot-ignore-generic-mode that handles this correctly.)

Published 13 May 2013
Tagged emacs, elisp and todo.

 

Spell checking cheat-sheet for emacs.

  • M-$ - ispell-word or ispell-region (depending on whether something is selected)
  • [SPACE] - Skip this word—continue to consider it incorrect, but don't change it here.
  • r newword [RETURN] - Replace the word, just this time, with new. (The replacement string will be rescanned for more spelling errors.)
  • R new [RETURN] - Replace the word with new, and do a query-replace so you can replace it elsewhere in the buffer if you wish. (The replacements will be rescanned for more spelling errors.)
  • a - Accept the incorrect word—treat it as correct, but only in this editing session.
  • A - Accept the incorrect word—treat it as correct, but only in this editing session and for this buffer.
  • i - Insert this word in your private dictionary file so that Aspell or Ispell or Hunspell will consider it correct from now on, even in future sessions.
  • m - Like i, but you can also specify dictionary completion information.
  • u - Insert the lower-case version of this word in your private dictionary file.
  • l word [RETURN] - Look in the dictionary for words that match word. These words become the new list of “near-misses”; you can select one of them as the replacement by typing a digit. You can use * in word as a wildcard.
  • C-g X - Quit interactive spell checking, leaving point at the word that was being checked. You can restart checking again afterward with C-u M-$.
  • x - Quit interactive spell checking and move point back to where it was when you started spell checking.
  • q - Quit interactive spell checking and kill the spell-checker subprocess.
  • ? - Help

Via the emacs FAQ.

Published 14 May 2013
Tagged emacs and cheatsheet.

 

Using (quoted-insert), or how to enter a newline character in the emacs minibuffer

To insert a newline character in the mini-buffer, use (quoted-insert)

C-q C-j

Via jwz.

Published 4 May 2013
Tagged emacs.

 

dos2unix in emacs

M-% C-q C-m [RETURN] [RETURN]

M-% is bound to (query-replace). C-q is bound to (quoted-insert), which allows C-m to insert the control character ^M.

Published 4 May 2013
Tagged emacs.

 

Case insensitive sort-lines in emacs.

M-x set-variable [RETURN] sort-fold-case [RETURN] t [RETURN]
M-x sort-lines
Published 7 May 2013
Tagged emacs.

 

Using js-mode's indent logic in js2-mode

Steve Yegge's js2-mode is a sweet major mode for working with JavaScript in Emacs, but its auto-indentation logic is notoriously frustrating.

Here's a somewhat hack-y workaround: switch to javascript-mode before calling indent-region and then switch back.

;; use js-mode's indent logic, by pressing C-M-| (C-M-S-\)
(defun rlw/js-indent-region () (interactive) (js-mode) (indent-region (region-beginning) (region-end)) (js2-mode) )
(define-key js2-mode-map (kbd "C-M-|") 'rlw/js-indent-region)

PS: I haven't yet had a chance to sort these out, but there are at least four or five JavaScript modes:

The first two are supposed to address js2-mode's indentation problems (among other enhancements).

Published 7 May 2013
Tagged emacs, elisp and javascript.

 

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