Can anyone explain how this regex works.
What i understand is
-It's a conditional regex that searches for words of the form "$x$x" or "$x$y$y$x": 
  % simple_grep '^(\w+)(\w+)?(?(2)\2\1|\1)$' /usr/dict/words
    output :
    beriberi
    coco
    couscous
    deed
    ...
    toot
    toto
    tutu

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1 -Is'nt the second \w+ useless as the first one would match all words
2-This is the conditional regex (?(2)\2\1|\1).
What is the the condition (2)? and secondly what is the ? before the condition .Is that to specify minimal match?
thanks
chimni

In reply to Conditional regex by chimni

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