Varlogkernlog

Varlogkernlog is a shorthand used in Linux administration to refer to the kernel log, the collection of messages emitted by the kernel during operation. It is not a fixed file name; the actual location depends on the distribution and logging system. Kernel messages are generated by printk and include boot diagnostics, driver messages, hardware events, and error reports. These messages help diagnose hardware problems, kernel panics, or driver failures.

Common locations include /var/log/kern.log on Debian-based systems with rsyslog, /var/log/messages on Red Hat-based systems, and entries routed through the systemd journal. In systems using systemd, persistent kernel logs are stored in the journal and may be accessed via journalctl -k or journalctl -b. The exact file or database that holds kernel messages varies by configuration, but the kern facility is designed to capture these messages across the system.

Kernel messages can also be viewed directly from the kernel ring buffer via dmesg; to see human-friendly times, use dmesg -T when supported. If persistent logs are enabled, these entries are written to the appropriate log files or the journal rather than merely existing in memory. Log rotation and retention for kernel logs are typically handled by standard system log management tools such as logrotate, with permissions restricting access to authorized users.

See also: dmesg, printk, syslog, journald, kernel logging facilities. The term varlogkernlog is used in documentation and tooling as a generic reference to the kernel’s log output, regardless of the specific storage location.