Update gravity-adv.sh

[dwin999]

This works much faster.

[jacobsalmela]

Could you explain--in detail--how your code works? It is definitely faster, but I want to understand how it works. Explain what each piece of code does. Thanks

[dwin999]

catting a file to stdin is much faster than looping over a file in bash.

cat /tmp/matter.txt | sort | uniq | sed '/^$/d' | I just copied your code.
awk -v "IP=$piholeIP" '{sub(/\r$/,""); print "address=/"$0"/"IP}' just formats the code to the dnsmasq format, removing any \r using awk regex.

[jacobsalmela]

I'm just not too familiar with all of the awk stuff. I have really only used the most basic to print a column.