99% of the time you can just use the local address to talk to yourself. This is just an example to show you how wrangle the ip address using awk. Rewrite the hosts file so the host itself can use it’s external address by name. Write out the basic stuff in hosts that doesn’t change then write out the current IP address.

The problem is, hexdump will give you 16 ascii characters surrounded by pipes and then a newline before printing the next 16. You can’t search for long strings that way…

Here’s a bunch of ways to get the ip addresses for all your network interfaces using ifconfig.