I have two CSV lists of email addresses (List A and B). Our marketing guys accidentally sent an email to people in List A instead of combining both lists before sending.
An email needs to be sent to people in List B that were not in List A.
How can I find out which email is in list B that's not in list A? I wrote a PHP script but for educational and when the marketing guys do the same accident again I would like know if there's linux commands to do this instead of running a PHP script. (I know I could just run the script but I'm sure there's a better way).
I found the following solution but it combines the lists rather than showing which email is in List B and not in List A: How to join two CSV files?