check the system log for unusual entries

 Logcheck analyses the system log for unuexpected entries that could
 indicate problems or security issues.
 .
 Log entries in the system log (produced by systemd-journald, rsyslog
 or another system-log-dameon) are checked against a customisable
 database of regular expressions (such as that provided by the
 logcheck-database package) to identify routine messages: anything
 that does not identified as routine is reported to the system
 administrator.
 .
 Logcheck was originally part of the Abacus Project of security tools,
 but has been rewritten.