What to look at when there is an OS Error in Linux
/var/log folder contains overall system notifications and messages recorded at system boot. The file /var/log/messages contain a variety of messages, such as mail, kern, auth, cron, daemon, and so on. Among the logs under /var/log the /var/log/messages is the most common one as the kernel / core system logs are held there. The kernel modules generally dumps there too. So, for problem diagnosis / monitoring the /var/log/messages is the primary log file to examine. The Ubuntu 20.04 system doesn’t record its log in /var/log/messages folder. However, it saves the record in the/var/log/syslog file. Red Hat family distributions (including CentOS and Fedora) use /var/log/messages and /var/log/secure where Debian-family distributions use /var/log/syslog and /var/log/auth.log.