1. add : Add a route.
2. flush :Remove all routes.
3. delete : Delete a specific route.
4. change : Change aspects of a route (such as its gateway).
5. get : Lookup and display the route for a destination.
6. monitor : Continuously report any changes to the routing information base, routing lookup misses, or suspected network partitionings.

Task: View / Display FreeBSD Routing Table

Use the netstat command with -r option as follows:
$ netstat -r
$ netstat -rn
Sample outputs:

Routing tables
 
Internet:
Destination        Gateway            Flags    Refs      Use  Netif Expire
default            61.221.xx.yy       UGS         0      247    em1
10                 10.10.110.5        UGS         0       50    em0
10.10.110/26       link#1             UC          0        0    em0
10.10.110.5        00:1b:0d:e6:58:40  UHLW        2        0    em0   1145
61.221.xx.yy/29    link#2             UC          0        0    em1
61.221.xx.yy       00:1b:0d:e6:57:c0  UHLW        2        0    em1   1055
61.221.xx/24       link#2             UC          0        0    em1
127.0.0.1          127.0.0.1          UH          0        0    lo0

The first two line displays default routes. To just print IPv4 routing table, enter:
# netstat -4 -r -n
Sample outputs:

Task: FreeBSD Set a default route

All network packets that cannot be sent according to the previous entries of the routing table are sent through the following default gateway:
# route add default 192.168.1.254

How do I save routing information to a configuration file?

If you reboot FreeBSD box, the routing configuration will be lost i.e. the routing information will not persist. You need to edit /etc/rc.conf file to set defaultroute:
# vi /etc/rc.conf
Set default route by editing defaultrouter variable:
defaultrouter="192.168.1.254"
Save and close the file.

Task: Start and Stop FreeBSD Configured Interfaces

To apply changes to a configuration file, you need to stop and restart the corresponding FreeBSD networking interface. The following command will also update routing information:
# /etc/rc.d/netif restart
# /etc/rc.d/routing restart
OR
# service netif restart
# service routing restart

How can I change or the default gateway from the FreeBSD CLI?

Use the following commands:
### [ delete the default route/gateway ] ###
# route del default
### [ now setup 192.168.1.254 as the default gateway for my FreeBSD box ] ###
route add default 192.168.1.254
Verify it:
# netstat -r -n

Further readings:

• Read man pages netstat, route, rc.conf, service