Linux: log files

Common Linux log files names and usage

Path	Description
/var/log/messages	General message and system related stuff
/var/log/auth.log	Authenication logs
/var/log/kern.log	Kernel logs
/var/log/cron.log	Crond logs (cron job)
/var/log/maillog	Mail server logs
/var/log/qmail/	Qmail log directory (more files inside this directory)
/var/log/httpd/	Apache access and error logs directory
/var/log/lighttpd/	Lighttpd access and error logs directory
/var/log/boot.log	System boot log
/var/log/mysqld.log	MySQL database server log file
/var/log/secure or /var/log/auth.log	Authentication log
/var/log/utmp or /var/log/wtmp	Login records file
/var/log/yum.log	Yum command log file.

GUI Tool

Debian:

sudo gnome-system-log

Log configuration: rsyslogd

vi /etc/rsyslog.conf
ls /etc/rsyslog.d/

Rotate log file using logrotate software.
Monitor logs files using logwatch software.