LINE: for each line of the file {
    PATTERN: for each exclude string {
      if it matches the exclude string
        skip to the next PATTERN
      else
        print the line
        skip to the next LINE
    }
  }

##</code><code>##

  LINE: for each line of the file {
    PATTERN: for each exclude string {
      if we must exclude this line
        skip to the next LINE
    }
    we weren't excluded by any pattern, so print the line
  }

##</code><code>##

  LINE: foreach my $line (@file1only) {
    foreach my $exclude (@strings) {
      chomp $exclude;
      next LINE if $line =~ $exclude;
    }
    # we weren't excluded by any of the patterns
    print OUT $line;
  }