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emacselisp

how to delete the repeat lines in emacs

I have a text with a lots of lines, my question is how to delete the repeat lines in emacs? using the command in emacs or elisp packages without external utils.

for example:

this is line a
this is line b
this is line a

to remove the 3rd line (same as 1st line)

this is line a
this is line b
Solution

  • Put this code to your .emacs:

    (defun uniq-lines (beg end)
  "Unique lines in region.
Called from a program, there are two arguments:
BEG and END (region to sort)."
  (interactive "r")
  (save-excursion
    (save-restriction
      (narrow-to-region beg end)
      (goto-char (point-min))
      (while (not (eobp))
        (kill-line 1)
        (yank)
        (let ((next-line (point)))
          (while
              (re-search-forward
               (format "^%s" (regexp-quote (car kill-ring))) nil t)
            (replace-match "" nil nil))
          (goto-char next-line))))))

    Usage:

    M-x uniq-lines