Re: [exim] bash or perl question

Marc Perkel wrote:
> There are probably people out there who just know how to do this in a
> simple way.
>
> I have two files. Both files are text files that have IP addresses on
> separate lines. Both are alphabetical. What I want to do is read file A
> and file B and create file C that has all the IP addresses in file A
> that do not match the addresses in file B.
>
> Trying a new spam processing trick creating a whitelist of every IP
> address where I got 10 or more hams and no spams. That way I can just
> have a host whitelist that I don't have to run through spamassassin.

Is file B a true sub-set of file A? That is it does not contain any
addresses that are not also in A? And does each address only appear
once in each file? If both of those are true, this will work:

cat fileA fileB | sort | uniq -u > fileC