Flags:

-A Append
-I Insert

Example using the append flag:

sudo iptables -t nat -A POSTROUTING -o eth0 -d 1.2.3.4 -j SNAT –to-source 5.6.7.8
!
sudo iptables -t nat -I hml -s 172.20.6.99 -j SNAT –to-source 10.94.43.10

Example using the insert flag:

iptables -t nat -I POSTROUTING 17 -o eth0 -d 1.2.3.4 -j SNAT –to-source 5.6.7.8

Delete a Rule:
sudo iptables -t nat -D hml
sudo iptables -t nat -D POSTROUTING
sudo iptables -t nat -D PREROUTING