@Peilonrayz it looks nice and it works as far as I tested. But I can think of a problem with that. I also need to access the x and i in that main for loop
I'll post this here now that is working. I'll have to run it in an environment which does not have to much RAM and maybe the guys have some improvements when it comes to RAM usage
take line1/file1 and loop through all the lines of file2 to check if there's no matching line. If there's no line, print line1 from file1 and go to the next one