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

A better script :

while read ip  
do  
    grep "$ip"  "$ips" > /dev/null 2>&1 && echo "$ip" >> ip.found || echo "$ip" >> ip.notfound  
done    

Name the script "searchip.sh"
Assume your input file is "iplist" ,set up variable and call like this:

ips=ips
cat iplist | sh searchip.sh

or

sh searchip.sh < iplist  

Then you get two files , one is ip found, other one is ip not found.
What you need is shell I/O redirection.

Answer 2

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)

Answer 3

$ script < list_of_ip_addresses

That's all you need.