How to find a list of ip addresses in another file

Question

I was given the task to see if we are advertising a list of ip addresses(3000). Not a good idea to do it manually, so I copied all the ip addresses that we are advertising i

Answer 1

If you sort the two files, you can use the comm command:

sort all_ip_addresses > all_ip_addresses_sorted
sort adverted_ip_address > advertised_ip_address_unsorted

comm -23 all_ip_addresses_sorted advertised_ip_addresses_sorted

will show the IP addresses that are not advertised, and:

comm -12 all_ip_addresses_sorted advertised_ip_addresses_sorted

will show the advertised IP addresses.

You can also avoid creating the separate sorted files by using process substitution:

comm -23 <(sort all_ip_addresses) <(sort advertised_ip_addresses)