Xah Lee, 2009-08-14, 2009-10-06, 2011-03-29
This pages tells you how to setup emacs's whitespace-mode, and how to use it.
Emacs 23 has this whitespace-mode feature. It renders spaces, tabs, newlines characters with a visible glyph.
This feature is useful for working with “tab separated values” (aka CSV, TSV) that's a common format for importing/exporting address books or spreadsheets. It's also important in whitespace-significant langs such as Python.
To use it, call “whitespace-mode”. (you can call a command by typing 【Alt+x】) The command will toggle it on and off, for current file. Call “global-whitespace-mode” to toggle it globally for current emacs session. There is also “whitespace-newline-mode” and “global-whitespace-newline-mode”. They only show newline chars.
The default rendering of whitespace-mode. Different placement and mix of whitespaces are rendered with different colors. Also, long lines are colored dark purple. (download whitespace_sample_file.txt)
A clean setup for whitespace-mode.
How to reduce colors in whitespace-mode?
Put the following in your emacs init file:
; make whitespace-mode use just basic coloring (setq whitespace-style (quote ( spaces tabs newline space-mark tab-mark newline-mark)))
How to make whitespace-mode use the pilcrow sign “¶” for newline instead of the dollar sign?
Put the following in your emacs init file:
;; make whitespace-mode use “¶” for newline and “▷” for tab. ;; together with the rest of its defaults (setq whitespace-display-mappings '( (space-mark 32 [183] [46]) ; normal space, · (space-mark 160 [164] [95]) (space-mark 2208 [2212] [95]) (space-mark 2336 [2340] [95]) (space-mark 3616 [3620] [95]) (space-mark 3872 [3876] [95]) (newline-mark 10 [182 10]) ; newlne, ¶ (tab-mark 9 [9655 9] [92 9]) ; tab, ▷ ))
In the above, the numbers are unicode char code in decimal. Depending on your choice of font, some glyphs may not show up with your font. If so, you can try the following choices for your line return char or tab char.
| Glyph | Unicode Code Point (Decimal) | Unicode Char Name |
|---|---|---|
| · | 183 | MIDDLE DOT |
| ¶ | 182 | PILCROW SIGN |
| ↵ | 8629 | DOWNWARDS ARROW WITH CORNER LEFTWARDS |
| ↩ | 8617 | LEFTWARDS ARROW WITH HOOK |
| ⏎ | 9166 | RETURN SYMBOL |
| ▷ | 9655 | WHITE RIGHT POINTING TRIANGLE |
| ▶ | 9654 | BLACK RIGHT-POINTING TRIANGLE |
| → | 8594 | RIGHTWARDS ARROW |
| ↦ | 8614 | RIGHTWARDS ARROW FROM BAR |
| ⇥ | 8677 | RIGHTWARDS ARROW TO BAR |
| ⇨ | 8680 | RIGHTWARDS WHITE ARROW |
See also: Best Fonts for Unicode ◇ Computing Symbols in Unicode.
How to delete all whitespaces?
| Command Name | Area of Action | Action |
|---|---|---|
| whitespace-cleanup | text selection | delete whitespace in a smart way |
| delete-trailing-whitespace | buffer | delete all trailing whitespaces |
| delete-whitespace-rectangle | selection as rectangle | delete whitespace in text selection start/end points as a rectangle |
For more fine control of deleting whitespaces, you can use use “query-replace”, or “query-replace-regexp”. (See: Find ＆ Replace with Emacs.)
How to insert Tab or Newline char?
The following methods works everywhere, including when you are in minibuffer.
To insert a literal tab char, press 【Ctrl+q Tab】.
To type a newline char, type 【Ctrl+q Ctrl+j】.
You need to use the above method to insert these characters, because for example in minibuffer, pressing Tab does name completion and pressing Enter finishes the prompt. In most programing language modes, pressing Enter or Tab also does some auto indenting and formatting.
For detail, see: Emacs's Key Notations Explained (/r, ^M, C-m, RET, <return>, M-, meta).