--open (Show only open (or possibly open) ports)

Sometimes you only care about ports you can actually connect to (open ones), and don't want results cluttered with closed, filtered, and closed|filtered ports. Output customization is normally done after the scan using tools such asgrep, awk, and Perl, but this feature was added due to overwhelming requests. Specify --open to only see hosts with at least one open, open|filtered, or unfiltered port, and only see ports in those states. These three states are treated just as they normally are, which means that open|filtered and unfiltered may be condensed into counts if there are an overwhelming number of them.