Added "S" and "D" to turn port display on/off.

iftop.8

@@ -58,6 +58,9 @@ Don't do hostname lookups. This setting may be altered at run time.
 Run in promiscuous mode, so that traffic which does not pass directly through
 the specified interface is also counted.
 .TP
+\fB-P\fP
+Turn on port display.
+.TP
 \fB-b\fP
 Don't display bar graphs of traffic. This setting may be altered at run time.
 .TP
@@ -129,6 +132,11 @@ for each source or destination will be aggregated together.  This is most
 useful when \fBiftop\fP is run in promiscuous mode, or is run on a gateway
 machine.
 
+.SH PORT DISPLAY
+
+\fBS\fP or \fBD\fP toggle the display of source and destination ports
+respectively.
+
 .SH SEE ALSO
 .BR tcpdump (8),
 .BR pcap (3),