Different Unix-like systems handle auditing differently. In Linux, the most common “audit” mechanism is syslogd(8), usually working in conjunction with klogd(8). You might also want to look at wtmp(5), utmp(5), lastlog(8), and acct(2). Some server programs (such as the Apache web server) also have their own audit trail mechanisms. According to the FHS, audit logs should be stored in /var/log or its subdirectories.