# clean lines with words in
$text =~ s/.*?             # anything
           (?:             # don't remember me
            (\w.*\w)       # everything from first to last word character
                           # on the line - remember this
            |              # or
            [^\w\s]{6,}    # at least 6 characters that aren't words or
                           # spaces (in a row) - forget me
           )
           .*              # the rest of the line
           /$1/gx;         # replace whole line with (\w.*\w) match,
                           # if made.