I've only recently started using emacs, for professional reasons. I'm trying to replace all double spaces in a text file by single ones using regex. In C-M-s the expression \s-\{2\} matches two spaces all right but also more which I don't want. And in a search and replace query the same expression doesn't match anything.

1 Answer 1


What you want to use interactively is this: \s-\{2\}, not this: \s-\\{2\\}.

That works for me, for both C-M-s (isearch-forward-regexp) and C-M-% (query-replace-regexp).

You edited your question, changing \s-\\{2\\} to \s-\{2\}. But I don't see a problem with the latter. It does not match more than two consecutive space chars, for me. And it does match two for query-replace also, for me.

(It can be confusing to go back and forth between entering a regexp interactively and using a regexp in Lisp code. Interactively you typically do not use \\.)

  • Sorry, I made a mystake in my post. I actually used \s-\{2\}
    – prof
    Mar 30, 2019 at 17:14
  • Then I think you'll need to give a more detailed recipe to repro the problem - step-by-step, starting from emacs -Q. I don't see a problem when I do that.
    – Drew
    Mar 30, 2019 at 17:15
  • It works when I do C-x h and then add the regex. So I guess it did not work because I was not selecting the whole text. Is that it?
    – prof
    Mar 30, 2019 at 17:50
  • You should not need to select any text. It's not clear to me what you're trying. Please edit the question to provide a step-by-step recipe of what you're doing - what keys you hit etc. You should be able to just use C-M-s or C-M-% directly, providing the regexp \s-\{2\}. (For the replacement text for C-M-% just type a single space char.)
    – Drew
    Mar 30, 2019 at 17:59
  • I am bit confused as well. I am new at this. But if I put the cursor at the beginning of the buffer or before the pattern I'm looking for, it works. Thank you for your help.
    – prof
    Mar 30, 2019 at 18:15

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