Removed the ambiguity in -s, -f, -p and -i flags handling.
Basically, there are four displays (except others):
1. PCB display.
2. Protocol statistics display. (-s)
3. Interface statistics display. (-i)
4. Per-interface protocol statistics display. (-i -s)
All of the above except 3) can be limited to a particular
protocol family (-f) or a single protocol (-p).
Some examples:
1. netstat -f inet -- show PCBs of all INET protocols
2. netstat -p udp -- show PCB of UDP protocol only (NEW!)
3. netstat -s -- show protocol statistics for all families
4. netstat -s -f inet -- show INET protocols statistics
5. netstat -s -p icmp -- show ICMP protocol statistics
This is a work in progress. Manpage has been fixed slightly,
but is still incomplete.
cf5e44f88e