Log files. They're there for a reason -- to keep track of what goes on behind the velvet curtain of your operating system. When things go wrong, entries are added to those log files, so you can view ...

This easy. Just type logger on the command line and your message will be added to the end of the /var/log/syslog file. $ logger comment to be added to log $ tail -1 /vvar/log/syslog May 21 18:02:16 ...