Emacs: Add Period to Line Ends 💠

This command add a period to each end of line in current text lock. This is a useful when you copy text from discord or twitter to your blog.

put this in your Emacs Init File:

(defun xah-add-period-to-line-end ()
  "Add a period to each end of line that does not have one.
Work on current paragraph if there is no selection.

URL `http://xahlee.info/emacs/emacs/emacs_period_to_line_end.html'
Created: 2020-11-25
Version: 2025-03-26"
  (interactive)
  (let (xbeg xend)
    (seq-setq (xbeg xend) (if (region-active-p) (list (region-beginning) (region-end)) (list (save-excursion (if (re-search-backward "\n[ \t]*\n" nil 1) (match-end 0) (point))) (save-excursion (if (re-search-forward "\n[ \t]*\n" nil 1) (match-beginning 0) (point))))))
    (save-restriction
      (narrow-to-region xbeg xend)
      (goto-char (point-max))
      (insert "\n")
      (goto-char (point-min))
      (while (search-forward "\n" nil 1)
        (backward-char)
        (let ((charX (char-before)))
          (if (or (eq charX ?\.) (eq charX ?!) (eq charX ??) (eq charX ?\n) (eq charX ?>))
              nil
            (insert ".")))
        (forward-char))
      (goto-char (point-max))
      (when (eq (char-before) ?\n) (delete-char -1)))))