If I understand what you're asking, each field -- each thing you're searching for -- will only appear once in the input, right? If that's the case, you can iterate over your hash of regexps for each line, BUT after you find a match, delete that particular key from the hash. When your hash is empty, you're done searching. Alternatively, you could iterate over the hash of regexps, but only try the match if $summary->{$key} wasn't set.