I have a specific problem that when I run "grep", my default grep command contains the -i option, and sometimes I wish to repeat the last search but case-sensitive. So I press M-p (previous command),

grep <some-options> -i lastSearchWord

then a number of M-b (backward-word) to get to the -i option, but this puts me between "-" and "i": so then I have to switch to C-b M-d to delete the option. And it's annoying to switch from Meta to Control here (and the need for this extra command at all): it would be more helpful to get the cursor to before the "-".

I know it's possible to redefine the categorization of characters per mode, but I am out of touch with Emacs terminology so don't know what to search for. How do I redefine "-" to be a "word character" in the Minibuffer only?

  • If you use lgrep you can just customize option grep-template to be what you want, i.e., to not include -i.
    – Drew
    Apr 1, 2022 at 17:32
  • The question title seems to be off-target, and you can probably come up with better tags...
    – Drew
    Apr 2, 2022 at 15:53
  • The original question's title is How to define "-" as a word character in minibuffer? You cannot get better than that, and I hate it when people who think they're doing something for the improvement actually make stuff worse. Such a waste.
    – Alexander
    Apr 4, 2022 at 7:14
  • I rolled back @ideasman42's edit.
    – Drew
    Apr 4, 2022 at 15:31
  • The reason to make this question more general is the delimiter character isn't important, someone else may ask "How to define "." as a word character in minibuffer in macOS?" and "How to define "?" as a word character in minibuffer for the German language?" - there is no need to be spesific about which delimiter exactly you want to change. That you want to change a delimiter is enough information.
    – ideasman42
    Apr 4, 2022 at 21:20

2 Answers 2


On my system, backward-kill-sexp (which I have on C-M-backspace) is the thing to execute after backward-word. That eliminates both the "i" and its preceding "-".

If you need to do this often, you might consider writing your own command:

(defun my-case-insensitive-grep ()
  "Call `grep' without the "-i" switch."
  (grep (s-replace " -i " " " (grep-default-command))))

Starting with Emacs 28.1, this can be done much like any other mode using a mode hook & modify-syntax-entry.

(add-hook 'minibuffer-mode-hook
  (lambda ()
    ;; Treat '-' as a word.
    (modify-syntax-entry ?- "w")))
  • 2
    Does minibuffer-mode-hook really exist? Seems to not be defined for me (26.1)
    – JeanPierre
    Apr 1, 2022 at 11:42
  • Yes, it does in emacs 29 (and probably in 28 as well: I haven't checked). It does not exist in 27.2 AFAICT and presumably not in anything earlier either.
    – NickD
    Apr 1, 2022 at 12:54
  • It went in to 28.1 with this commit: "commit 55db25b2579e5d84dfcf3a15957fc7a827abf25f Author: Alan Mackenzie <[email protected]> Date: Tue Apr 20 10:14:40 2021 +0000 Introduce and use minibuffer-mode. This fixes bug #47150 ...`
    – NickD
    Apr 1, 2022 at 12:57
  • This is a future answer, presumably. Neither Emacs 28 nor Emacs 29 have been released. The latest release is 27.2.
    – Drew
    Apr 1, 2022 at 17:27
  • Emacs 28.1 has now been released.
    – ideasman42
    Apr 4, 2022 at 21:17

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.