I see, I was matching the minimum which was 0 \s's and 0 spaces.

Your example works, except in the case of: 

echo -e 'zero\none\ntwo    three' | perl -0777 -pe 's{\s*(one\ntwo)\s*
+^( *)}{\n\n<begin block>\n\n$1\n\n<end block>\n\n$2}m'
zero
one
two    three

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In reply to Re^2: matching and mysterious captures by Allasso
in thread matching and mysterious captures by Allasso

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