Examples:

The first example flushes all the gatewayed routes from the main table (f.e. after a routing daemon crash).

netadm@amber:~ # ip -4 ro flush scope global type unicast

This option deserves to be put into a scriptlet routef. 1cm NB. This option was described in the route(8) man page borrowed from BSD, but was never implemented in Linux.

The second example flushes all IPv6 cloned routes:

netadm@amber:~ # ip -6 -s -s ro flush cache
3ffe:2400::220:afff:fef4:c5d1 via 3ffe:2400::220:afff:fef4:c5d1 \
  dev eth0  metric 0 
    cache  used 2 age 12sec mtu 1500 rtt 300
3ffe:2400::280:adff:feb7:8034 via 3ffe:2400::280:adff:feb7:8034 \
  dev eth0  metric 0 
    cache  used 2 age 15sec mtu 1500 rtt 300
3ffe:2400::280:c8ff:fe59:5bcc via 3ffe:2400::280:c8ff:fe59:5bcc \
  dev eth0  metric 0 
    cache  users 1 used 1 age 23sec mtu 1500 rtt 300
3ffe:2400:0:1:2a0:ccff:fe66:1878 via 3ffe:2400:0:1:2a0:ccff:fe66:1878 \
  dev eth1  metric 0 
    cache  used 2 age 20sec mtu 1500 rtt 300
3ffe:2400:0:1:a00:20ff:fe71:fb30 via 3ffe:2400:0:1:a00:20ff:fe71:fb30 \
  dev eth1  metric 0 
    cache  used 2 age 33sec mtu 1500 rtt 300
ff02::1 via ff02::1 dev eth1  metric 0 
    cache  users 1 used 1 age 45sec mtu 1500 rtt 300

*** Round 1, deleting 6 entries ***
*** Flush is complete after 1 round ***
netadm@amber:~ # ip -6 -s -s ro flush cache
Nothing to flush.
netadm@amber:~ #

The third example flushes BGP routing tables after a gated death.

netadm@amber:~ # ip ro ls proto gated/bgp | wc
   1408    9856    78730
netadm@amber:~ # ip -s ro f proto gated/bgp

*** Round 1, deleting 1408 entries ***
*** Flush is complete after 1 round ***
netadm@amber:~ # ip ro f proto gated/bgp
Nothing to flush.
netadm@amber:~ # ip ro ls proto gated/bgp
netadm@amber:~ #