How can I display tabs as characters?

Question

When I work on files in python, I sometimes mistake tabs for spaces and vice versa. Is there a way I can get Vim to display a character for a tab instead of a tab?

Answer 1

Yes, use listchars:

set list
set listchars=tab:>-

If you put these two lines in your .vimrc, tabs will be shown as > for the start position and - through the rest of the tab.

(Sidenote: listchars can also show trailing spaces with trail:x (replace x with the character you want to use for a trailing space), which can be useful as well.)

Answer 2

The basic answer is :set list, which causes tabs to display as ^I.

However, I recommend going beyond that. Just :set list is problematic in that it fails to preserve visual alignment on screen. For example:

%.o: %.cpp
^Ig++ -c $<

doesn't look good, especially when you expect the g of g++ to appear under the first p of cpp (assuming tabstop=8).

Therefore, I suggest that in your .vimrc you put something like :set listchars=tab:␉· (To be clear, that's Unicode character U+2409 SYMBOL FOR HORIZONTAL TABULATION followed by U+00B7 MIDDLE DOT.)

As explained in :help listchars, a two-character setting for tab:xy causes visual alignment to be preserved:

tab:xy        Two characters to be used to show a tab.  The first
              char is used once.  The second char is repeated to
              fill the space that the tab normally occupies.
              "tab:>-" will show a tab that takes four spaces as
              ">---".  When omitted, a tab is show as ^I.

The example above would appear on screen as:

%.o: %.cpp
␉·······g++ -c $<

---

Personally, I go all-out with my listchars:

:set listchars=eol:⏎,tab:␉·,trail:␠,nbsp:⎵

• For eol, I use U+23CE RETURN SYMBOL
• For trail, I use U+2420 SYMBOL FOR SPACE
• For nbsp, I use U+23B5 BOTTOM SQUARE BRACKET

These characters are distinctive enough that they rarely appear literally in document text.

To type these special characters into your vimrc, type Ctrl-vu23CE while in Insert Mode, as explained in :help utf-8-typing.

Answer 3

Highlighting tabs

Temporary Tab highlighting

For occasional use, one can simply highlight all tabs in a document using the following search / command:

/\t

To remove the highlighting, simply type :noh which is short for :nohlsearch —no high lighting.

Permanent Tab highlighting

" Highlight tabs as errors.
" https://vi.stackexchange.com/a/9353/3168
match Error /\t/

More highlighting

For more of these useful highlighting commands —including combined with trailing whitespace and making this permanent— see the Vim wiki.

Answer 4

I personally like the use of the plugin indentLine, which displays a vertical line at indentation levels.

It is of great help especially in python, where the indentation is important.

Among other things, it provides a toggle command, that can be mapped to a key combination, so that you can turn it off, when you don't need it.

Answer 5

Easiest method is to do :set list, which will show tabs as ^I and end of line as $.

I like to use a mapping that calls

:set invlist 

to toggle between regular display and list display.

For example:

:nmap <leader>l :set invlist<cr>

This allows me to quickly check if there are tab vs space problems and then go back to a regular display.

Answer 6

You may want to show tabs differently in a regular terminal and gvim.

set list!
if has('gui_running')
    set listchars=tab:▶\ ,trail:·,extends:\#,nbsp:.
else
    set listchars=tab:>.,trail:.,extends:\#,nbsp:.
endif

(Adding for completeness, in case others find it useful).

Answer 7

This can be easily achieved using listchars by specifying the tab as: ,tab:\ \ ┊,

By providing two escaped spaces in front of your tab declaration, vim will repeat the spaces. This is opposed to the default, where vim prefers the second character as the repeating character.

This achieves a similar effect to using a plugin like IndentLine without the overhead. Here's an example of what it might look like using the following complete listchars config:

set listchars=eol:↓,tab:\ \ ┊,trail:●,extends:…,precedes:…,space:·

Answer 8

I combined @john-om approach with this character Unicode Character 'ZERO WIDTH SPACE' (U+200B) and indentLine plugin. So, if I use spaces, plugin show nice formated indents, if I use tabs, pipes are the only visible mark and that is what I want. I can also toggle tab's marks.

" indicate tabs
:nmap <leader>l :set invlist<cr>
set list listchars=tab:❘⠀,trail:·,extends:»,precedes:«,nbsp:×

Answer 9

I like VSCode's "render whitespace" display

I customize vim's space and tab chars like vscode, i.e. use dark gray color dot for space char, use arrow char for tab.

My vim configuration

"\u21A6 is ⇥
"set listchars=eol:$,tab:⇥¬¬,trail:·,extends:>,precedes:<,space:·
" 0x1F862 is 🡢
" https://vi.stackexchange.com/questions/422/displaying-tabs-as-characters
set listchars=tab:🡢\ ,trail:·,extends:>,precedes:<,space:·
" Set the list char color
" https://vi.stackexchange.com/questions/6136/how-to-dim-characters-from-set-list/6140#6140
" :hi SpecialKey ctermfg=grey guifg=grey50
" https://gist.github.com/morumo/9405368
:hi SpecialKey ctermfg=darkgray guifg=gray70

My emacs configuration

Btw, I also tried to configure the render display in my emacs configuration:

;; https://github.com/jameshintaro/.emacs/
;;http://ergoemacs.org/emacs/whitespace-mode.html
(require 'whitespace)
(setq whitespace-style
      '(face tabs tab-mark spaces space-mark))

(setq whitespace-display-mappings
      '(
        (space-mark ?\u3000 [?□])  ; 全角スペース
        (space-mark ?\u0020 [?\xB7])  ; 半角スペース
        (newline-mark ?\n   [?$ ?\n]) ; 改行記号
        ;(tab-mark   ?\t   [?\x2192 ?\t]) ; tab
    (tab-mark   ?\t   [?\x1F862 ?\t]) ; tab
        ) )

(setq whitespace-space-regexp "\\([\x0020\x3000]+\\)" )

;(set-face-foreground 'whitespace-space "Goldenrod1")
(set-face-foreground 'whitespace-space "Azure4")
(set-face-background 'whitespace-space 'nil)
(set-face-bold-p 'whitespace-space t)

;;(set-face-foreground 'whitespace-tab "DarkOliveGreen1")
(set-face-foreground 'whitespace-tab "Azure4")
(set-face-background 'whitespace-tab nil)
(set-face-underline  'whitespace-tab t)

;;(set-face-foreground 'whitespace-newline  "DimGray")
;;(set-face-background 'whitespace-newline 'nil)

Which looks like the following: