Document keys for switching display modes and sorting on 'sent' or 'received'

numbers - thanks to Bobly for the trigger

nethogs.8

@@ -16,19 +16,39 @@ nethogs \- Net top tool grouping bandwidth per process
 NetHogs is a small 'net top' tool. Instead of breaking the traffic down per protocol or per subnet, like most such tools do, it groups bandwidth by process - and does not rely on a special kernel module to be loaded. So if there's suddenly a lot of network traffic, you can fire up NetHogs and immediately see which PID is causing this, and if it's some kind of spinning process, kill it. 
 
 .SS Options
-The \fB-d\fP switch delay for refresh rate.
-.PP
-The \fB-h\fP switch display available commands usage.
-.PP
-The \fB-p\fP switch sniff in promiscious mode (not recommended).
-.PP
-The \fB-t\fP switch tracemode.
-.PP
-The \fB-V\fP switch prints Version info.
+.TP
+\fB-d\fP
+delay for refresh rate.
+.TP
+\fB-h\fP
+display available commands usage.
+.TP
+\fB-p\fP
+sniff in promiscious mode (not recommended).
+.TP
+\fB-t\fP
+tracemode.
+.TP
+\fB-V\fP
+prints Version info.
 .PP
 .I device(s)
 to monitor. By default eth0 is being used.
 
+.SH "INTERACTIVE CONTROL"
+.TP
+m
+cycle between display modes (kb/s, kb, b, mb)
+.TP
+r
+sort by 'received' 
+.TP
+s
+sort by 'sent'
+.TP
+q
+quit
+.RE
 .SH "SEE ALSO"
 .I netstat(8) tcpdump(1) pcap(3)
 .SH AUTHOR