Since he is comparing line by line instead of the whole doc all at once, it doesn't matter that the next regex starts at the begging even if the last one matched. I know that often my problem isn't getting perl to do what i want, it is thinking i want perl to do one thing when realy there is a better solution. That's why it is good you provide your actual problem because someone might see a solution you are missing, or at very least the insight into the problem will allow people to agree you are doing it the best way, either way you get good information!