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I'm using emacs 24.

How can I replace all occurrences of the non-printable Unicode bidi character RTL, whose hexadecimal number is 202e? I want to replace it with the non-printable Unicode bidi character LTR, whose hexadecimal number is 202d?

Could someone give me some guidance?

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migrated from stackoverflow.com Nov 12 '12 at 22:31

This question came from our site for professional and enthusiast programmers.

This requires enable-recursive-minibuffers is set to non-nil:

M-x replace-regexp RET C-x 8 RET 202e RET RET C-x 8 RET 202d RET RET

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I didn't know about C-x 8 RET! – user4815162342 Nov 12 '12 at 20:54
    
Thanks, but unfortunately this solution doesn't work. I still get the message "Replaced 0 occurrences". – Evan Aad Nov 13 '12 at 6:45
1  
@EvanAad: Is it possible the point was after the character to be replaced? – npostavs Nov 18 '12 at 5:09
    
I've retried and it works! Thanks! – Evan Aad Nov 21 '12 at 14:53
up vote 2 down vote accepted
  1. Add the following piece of emacs Lisp code at the beginning of the buffer:

    (while (re-search-forward "\u202e" nil t)
            (replace-match     "\u202d"))

  2. Place the cursor just after the last parenthesis and type C-xC-e to execute the code.

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M-x replace-regexp RET \u202e RET \u202d
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You'd think, wouldn't you!? Unfortunately, running this command on a file that consists of a single unicode character, whose hex number is 202e, yields the following message: "Replaced 0 occurrences" – Evan Aad Nov 12 '12 at 18:55
    
This one doesn't work for me either, and I don't see why it should be expected to work. – npostavs Nov 18 '12 at 5:15

Type the following:

M-% C-q 20056 RET RET C-q 20055 RET RET

C-q followed by an octal number and RET will insert the character represented by the octal number and discard the RET. To quickly convert hex to octal, type #x202e in a M-: prompt, which will print the resulting number in decimal, octal, and hex.

To enable easier input of decimal numbers, a la GTK's C-S-u binding, I use this in my .emacs:

(global-set-key [(control shift u)]
                (lambda ()
                  (interactive)
                  (let ((read-quoted-char-radix 16))
                    (call-interactively 'quoted-insert))))
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Thanks, but i still get "Replaced 0 occurrences". – Evan Aad Nov 13 '12 at 6:47
    
This does work for me. But I wonder why not just have read-quoted-char-radix always be 16? – npostavs Nov 18 '12 at 5:14
    
@npostavs I've retried and it still doesn't work for me. – Evan Aad Nov 21 '12 at 14:56

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