Simple Log Watcher, or Swatch.pl, started out as the "simple watchdog" for activly monitoring log files produced by UNIX's syslog facility. It has since been evolving into a utility that can monitor just about any type of log. Stephen E. Hansen and Todd Atkins. Automated system monitoring and notification with Swatch.
In Proceedings of the USENIX Systems Administration (LISA VII) Conference, pages 145-155, November 1993.