The character class in your second example doesn't include ':' among the permitted characters, and this stops it being able to match the original duplicated substring. As a result it walks through the string looking for a duplicate that it can match, and 'd: d' is the first one it finds.

To match the initial duplicate with the character class, add the colon to the character class:

  s/([:()\w\s-]+): \1/$1/;

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Hugo

In reply to Re: Understanding regex by hv
in thread Understanding regex by Hena

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