Directories you want to know about

• /etc/[appname] – where [appname] is probably configured

• /etc/init.d – where app startup/shutdown scripts are kept

• /etc/rc[0-6].d – where the system looks for links to automatically run init.d scripts at startup or shutdown

• /var/spool/cron/crontabs – where scheduled jobs are stored

• /var/lib/mysql – where the MySQL db stores its binary data

• /var/run – where apps store lockfiles - [appname].pid

• /var/www – the default location for Apache websites

• /tmp – where you put stuff you only need for a little while

• /home – nobody cares about this but you

• /dev – where all the devices live

• /proc – where system info lives, and you can poke at the kernel