Try the pattern below.
A lot of keys: a posix, the space that separates the letters, etc.
Really, thanks a lot.
You're welcome. I'm glad I could help.
But I'd like to make a little correction to my previous pattern, to avoid unwanted matches like "sing an anthem", "thinking of offices" and "apples or oranges".
Please use this Find pattern instead:
This one will require at least one letter before the duplicated pair.
If you want a detailed explanation of the pattern, feel free to ask.
Yes, it improves the first formulae!
This grep requires a visual control as the frequency of unusual casual concordances of two identical letters are real although scarce:
Your formulae is easily read because you cleared the problem.
Is like seeing a sudoku already filled... seems easy, after.
In the second formulae is very good the +lookbehind that I also missed.
You're definitely right, Camilo: with so much legimate cases of duplicate pairs, this is a scenario where "Replace All" is absolutely forbidden. The conservative "Find->Change/Find" approach is a much safer bet :-)