destination        The destination host or network (with or
                       without the optional Classless Inter-Domain
                       Routing (CIDR) mask (/bitmask)).

    gateway            The next hop and gateway to which packets
                       should be addressed. Routes to a particular
                       host are distinguished from those to a
                       network by interpreting the Internet address
                       associated with destination.

    [-net | -host]     Forces the destination to be interpreted
                       as a network addres or as a host address,
                       respectively. Otherwise, if the destination
                       has a local address part of INADDR_ANY, or
                       if the destination is the symbolic name of a
                       network, then the route is assumed to be to
                       a network; otherwise, it is presumed to be a
                       route to a host.

                       For example, 128.32 is interpreted as -host
                       128.0.0.32, 128.32.130 is interpreted as -host
                       128.32.0.130; -net 128.32 is interpreted as
                       128.32.0.0, and -net 128.32.130 is interpreted
                       as 128.32.130.0.

    [family]           Specifies the optional address family of the
                       destination and gateway parameters. Possible
                       values are: -inet (the default) and -inet6.
                       If the -link parameter is not specified,
                       this also specifies the address family of
                       the gateway parameter.

    [-link]            Specifies that the gateway is a link layer
                       address. If the -link parameter is not
                       specified, the address family of the gateway
                       parameter is the same as the destination.

    The optional modifiers -rtt, -rttvar, -sendpipe, -recvpipe, -
    mtu, -hopcount, -expire, and -ssthresh provide initial values
    to metrics maintained in the routing entry. These may be
    individually locked by preceding each such modifier to be locked
    by the -lock meta-modifier, or one can specify that all ensuing
    metrics may be locked by the -lockrest meta-modifier.

    The optional modifiers -reject and -blackhole specify route
    behavior different from a normal route. A normal route allows
    packets to be forwarded out on it. Packets sent to reject routes
    are dropped and messages designating the route as unreachable
    are sent to the packet originators. Packets sent to blackhole
    routes are also dropped, but no notification is sent to the
    packet originators. In both cases, you must specify 127.0.0.1
    (localhost) as the gateway argument.

    The -netmask mask option specifies the subnet mask to use for
    the routing entry. Networks that use a nonstandard subnet must
    include this option. Specify this option after any optional
    modifiers. Do not specify this option if you specify a CIDR
    bitmask (/bitmask).

    If the flush command is specified, route will flush the routing
    tables of all gateway entries. One can choose to flush only
    those routes whose destinations are of a given address family by
    specifying an optional keyword describing which address family.