/var/log/syslog

rsyslog

cat /etc/rsyslog.conf

ls /etc/rsyslog.d/

20-ufw.conf  21-cloudinit.conf  50-default.conf

logger

ls /etc/logrotate.d/

alternatives  apport  apt  dpkg  lxd  rsyslog  ufw  unattended-upgrades

cat /etc/logrotate.conf

cat /etc/cron.daily/logrotate

journalctl

journalctl –dmesg

journalctl -u unit

journalctl -u crond –since yesterday –until 9:00 -p info

cat /etc/systemd/journald.conf

systemctl start systemd-journald