Application LogsĪpplication logs store information relevant to any application that is executed. This can be useful for debugging purposes. The syslogd daemon can forward log messages as well. The path for the system login daemon’s configuration is /etc/nf.Įach file consists of a selector and an action entry field. These logs have their own category of logs and are seen as the heart of the logging operations for any system. /var/log/kern.log: Kernel logs (the kernel log stores information from the Ubuntu Linux kernel)Ī daemon log is a program that runs in the background and is essential for system operations./var/log/maillog: Mail server logs (the mail log stores information related to mail servers and archiving emails)./var/log/daemon.log: Daemon logs (the daemon log contains information about events related to running the Linux operation)./var/log/debug: Debug logs (the debug log stores detailed messages related to debugging and is useful for troubleshooting specific system operations)./var/log/mysqld.log: MySQL database server log file./var/log/httpd/: Apache access and error logs./var/log/auth.log: Auth logs (the authentication log stores all authentication logs, including successful and failed attempts).

/var/log/boot.log: System Boot log (the boot log stores all information related to booting operations).

On its own, it contains the most significant amount of information about system functionality. Systems log files are needed for Linux to work. Many of these logs can be located in the var/log subdirectory. Most directories can be grouped into one of four categories: A good understanding of each type of file will help how to distinguish the respective logs. Logs can tell a lot about the operations of a system. l, -loop loop output forever until killed.Note: Check out our comprehensive guide on grep to learn how to use it with examples. w, -overwrite overwrite the existing log files.

with 'byte' option, the logs will be split whenever the maximum size in bytes is reached. with 'number' option, the logs will be split whenever the maximum number of lines is reached. examples: 10, 20ms, 5s, 1m -p, -split-by integer set the maximum number of lines or maximum size in bytes of a log file. examples: 10, 20ms, 5s, 1m -d, -delay duration delay log generation speed (default unit 'seconds'). s, -sleep duration fix creation time interval for each log (default unit 'seconds'). 'bytes' will be ignored when 'number' is set. b, -bytes integer size of logs to generate (in bytes). available types: - stdout (default) - log - gz -n, -number integer number of lines to generate. (default 'generated.log') -t, -type string log output type. available formats: - apache_common (default) - apache_combined - apache_error - rfc3164 - rfc5424 - json -o, -output string output filename.

Common log file system