Add static routes on Mac OS X and BSD descendants

Add a static route:

# route -n add -net 192.168.122.0/24  192.168.0.117

This is equivalent to the Linux command:

# route add -net 192.168.122.0 netmask 255.255.255.0 gw 192.168.0.117

List routing tables:

# netstat -r