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.

WWW: http://metalog.sourceforge.net/