If at say 10:25, the situation at 10:20 is known, it obviously can't change five minutes later. Also if the log file is large, the File::Tail
will perform better than the implicit costs of closing, reopening and reading backwards every time anyway. The advantage of that one over the POE solution is that you can sleep for 300 seconds in between to minimise consumption of system resources, whereas POE will keep itself somewhat busier, though not as busy as reading backwards every time.
But it often helps in busier systems to divide very regular processing into small slots by design, so that the next daemon to be implemented has a slot available whose consumption by other processes can reasonably be predicted - that can't be done for the POE solution.