How can you remove one email database from another in macOS?

Question

macOS

I have a base of subscribers and a base of those who unsubscribed, how can I quickly remove one base from another? I used to have a program for windows that did it in a fraction of a second, but now I'm working on mac and it no longer fits here

Answer 1

sort -u sub.txt > sub.tmp
sort -u unsub.txt > unsub.tmp
comm -2 -3 sub.tmp unsub.tmp > result.txt
rm *.tmp