How to parse an IP address in bash?

Question

linux

I am raising DNS and at the same time gaining experience in linux and bash. Unloaded a large zone from the windows-dns-server, which contains A-records on 2 subnets.
Actually, for future convenience, I want to write a script that would parse this unloaded zone and convert it into a PTR-readable file
Actually, you need to parse 192.168.20.10 and bring it to the result 10.20.168.192. Tell me how to do it?

Answer 1

something like this:

% echo "192.168.20.10" |awk -F. '{print $4"."$3"."$2"."$1}'
10.20.168.192