I have:

(setq mode-line-end-spaces "string")

That displays string in the mode-line.
How can I get string in red there?

2 Answers 2


You need to create a string with the appropriate face. You do that by attaching a face text property to the string, giving it value of some face (predefined or defined for the specific purpose - you can look at all the predefined faces with M-x list-faces-display and pick one from there, or you can define your own face). E.g. here's a snippet to use a predefined face:

(setq s (copy-sequence "sring"))
(put-text-property 0 6 'face 'custom-invalid s)
(setq mode-line-end-spaces s)

@NickD provided a good answer: use a face.

OP's comment to Nick's answer says that he'll try to write a function that, given a string, returns a propertized string. Such functions already exist: propertize does that, and so does add-face-text-property.

For example:

(setq ss  (propertize "abcde" 'face '(:foreground "red")))


(setq ss  "abcde")
(add-face-text-property 0 (length ss) '(:foreground "red") nil ss)
  • That's good to know. Thanks.
    – Gabriele
    Commented Jul 23, 2020 at 21:08
  • You should not try to modify a literal string: (setq ss (copy-sequence "abcde")).
    – user19761
    Commented Jul 25, 2020 at 11:42
  • @Fólkvangr: Depends on what behavior you want. Do you want to modify a copy of the original string or the original string? The example of using a literal string here is also for brevity - who knows where the actual original string comes from? But if the intention is to modify the original string, then you don't want to use copy-sequence.
    – Drew
    Commented Jul 25, 2020 at 16:15
  • @Drew: copy-sequence allows to create a mutable string (c.f. Elisp manual version 27, section 2.9 Mutability). In your sample code, add-face-text-property modifies a literal string.
    – user19761
    Commented Jul 25, 2020 at 17:19
  • @Fólkvangr: Yes, I know. And? If you can modify something then it's mutable. But all of this is extraneous. If you prefer, read "Suppose that the value of ss is a string", instead of the setq. The point of the answer is that you can use add-face-text-property to add color to a string.
    – Drew
    Commented Jul 25, 2020 at 18:15

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