-ip route add 192.168.$SUB.160 via 192.168.$SUB.231 dev eth0
-ip route add 192.168.$SUB.231 via 192.168.$SUB.160 dev eth0
-ip route add 192.168.0.53 via 192.168.$SUB.160 dev eth0
+ip route add 192.168.$SUB.160 via 192.168.$SUB.231 dev $eth
+ip route add 192.168.$SUB.231 via 192.168.$SUB.160 dev $eth
+ip route add 192.168.0.53 via 192.168.$SUB.160 dev $eth