Metalog is a modern replacement for syslogd and klogd. The logged messages can be dispatched according to their facility, urgency, program name and/or Perl-compatible regular expressions.
Log files can be automatically rotated when they exceed a certain size or age. External shell scripts (ex: mail) can be launched when specific patterns are found. Metalog is easier to configure than syslogd and syslog-ng, accepts unlimited number of rules and has (switchable) memory bufferisation for maximal performance.