Emacs 24.4 (date 2014-10)

By Xah Lee. Date: 2014-03-08. Last updated: 2023-09-16.

This page is a on-going list of tips and tricks about Emacs 24.4. (released in 2014-10)

If you are on linux and need to build it, see: Emacs: How to Build Emacs on Linux

Editing Features

snake_case superword-mode

Move cursor by jumping over _. For example: “snake_case”

See: Emacs init: Move Cursor by camelCase, snake_case (subword-mode)

isearch-forward-symbol-at-point

new isearch-forward-symbol-at-point

Emacs: Search Text

Auto Indentation

electric-indent-mode is on by default. Now, pressing Return also does indentation. To insert line-break without indent, press Ctrl+j.

Or, turn off:

(electric-indent-mode 0) ; make return key not auto indent

indent-rigidly 【Ctrl+x Tab】 changed. Call it, then press {←, →} to adjust indentation, or press {Shift+←, Shift+→} to adjust indentation by tab width.

By default, the selection is the beginning of current block up to current line.

Type any other key to exit.

Delete Duplicate Lines

delete-duplicate-lines will delete duplicated lines in current text selection. The lines need not be sorted. You can try it on this:

aaa
bb
cc
aaa
bb
aaa
bb

You can use linux shell tool to do the same. [see Emacs: shell in emacs]. However, shell command have problems with Unicode, and does not work well on Microsoft Windows. [see Unix Shell Util uniq Unicode Bug]

[see Emacs: List Matching Lines]

rectangle-mark-mode

emacs 24.4 has a rectangle-mark-mode 【Ctrl+x Space】.

Alt+x rectangle-mark-mode, then move cursor to highlight a rectangular area. Press Delete ⌦ will delete text in that rectangle area.

This feature was part of cua-mode in emacs before.

Emacs: Edit Column Text, Rectangle

Display “lambda” as λ

emacs pretty lambda 2021-09-25 g9TW — emacs pretty lambda

emacs init: Display Lambda as λ

cycle-spacing

New command cycle-spacing. It's like a smart just-one-space. When called repeatedly, it cycles between: one space, no space, original spacing. (this is useless)

[see Emacs: Delete Whitespace around Cursor 📜]

Bi-direction Text Arrow Key Direction

new variable: visual-order-cursor-movement. When true (t), ← always moves to the left, → always moves to the right, disregarding the surrounding bidirectional context.

File Features

Unique Buffer Names

emacs 24.4, by default, buffer names are unique. This is done by:

;; uniquify buffer names
(require 'uniquify) ; bundled with GNU emacs 23.2.1 or before. On in 24.4
(setq uniquify-buffer-name-style 'post-forward-angle-brackets) ; emacs 24.4 style, for example: cat.png<dirName>

Alt+x describe-variable then type uniquify-buffer-name-style to see examples of different style.

desktop-save-mode auto Save/Restore

With desktop-save-mode on, now it automatically save/restore opened files, windows config (number of windows, size, position), when quit and restart emacs.

new variable desktop-save. Default is t. When t, desktop are automatically saved when you quit.

new variable desktop-auto-save-timeout. Default value is 30 (seconds). It specifies the time interval to periodically save “desktop”. Before, it saves only when you quit emacs.

New variable desktop-restore-frames. Default value is t. When t, save and restore the frame and window configuration.

emacs init: Restore Opened Files (desktop-save-mode)