my $re = qr/
             <p>         # paragraph-open
             (           # Capture
              (?:         # group
               (?!<\/p>)    # Make sure we aren't at a paragraph-close
               (?!\[tab\])  # and we're not at [tab]
               .            # consume a char
              )*          # any number of times
              \[tab\]     # consume [tab] (hooray!)
              .*?        # anything up to paragraph-close
             )
             <\/p>               /x;
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Update: to not capture paragraph tags

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Caution: Contents may have been coded under pressure.

Comment on Re: Matching set of paragraph tags with string inside. Download Code