Dmesg

grep -Ei -B 1 -A 1 "crit|err[^u]|warn|fail[^2]|alert|unknown|unable|miss|except|disable|invalid|cannot|denied|broken|exceed|unsafe|unsolicited" \
   /var/log/dmesg

See also

• Linux Logging: logger systemd-cat journalctl, syslog, rsyslogd logrotate, sshd logs, Logwatch, logcheck, Container logging, Journalctl logs, journald.conf, Docker logs, ts