I managed to display the current buffer and complete file path in the title bar with the following snippet

(setq frame-title-format
                            '(buffer-file-name "%b - %f" ; File buffer

But the line-number-at-pos does not work, i.e. the current line number is not displayed. What am I doing wrong here?

Also, is there an efficient way to display the lines of code in the currently visited file as well?

1 Answer 1


Interesting that the %l is indeed ignored for the frame-title-format. But you can wrap line-number-at-pos in an eval form and return a string:

(setq frame-title-format
      '("%b - %f " (:eval (number-to-string (line-number-at-pos)))))

;; To have it working on line change you have to add this to post-command-hook:
(add-hook 'post-command-hook
          #'(lambda () (setq frame-title-format
      '("%b - %f " (:eval (number-to-string (line-number-at-pos)))))))

;; To add total line count, use this instead (remove above hook first)
(add-hook 'post-command-hook
          #'(lambda () (setq frame-title-format
      '("%b - %f " (:eval (number-to-string (line-number-at-pos))) ":"
        (:eval (number-to-string (count-lines (point-min) (point-max))))))))

To display lines of code you can activate display-line-numbers-mode.

  • thanks. Unfortunately this does not update dynamically but only upon certain actions like e.g. isearch
    – CD86
    Jun 23 at 15:14
  • as for the total number of lines per file, I dont want to have visual noise in the form of a large column with line numbers but rather one integer which specifies the total line numbers
    – CD86
    Jun 23 at 15:20
  • see a working example now. Since changing the line numbers dynamically requires a refresh, you have to somehow add the the expression to a hook
    – dangom
    Jun 23 at 17:11
  • many thanks good sir!
    – CD86
    Jun 23 at 19:24
  • still does not update upon using c-n and c-p oO
    – CD86
    Jun 27 at 7:25

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