Linux Directories and Files Cheat Sheet

Just a memory dump for important files and directories.

runs on interactive login
runs from .bashrc (if uncommented…)
Emacs settings
file that controls scheduled running of scripts
/etc/cron.d/hourly, daily, weekly, monthly
for running scripts on a scheduled basis
groups in the system
hard-coded hosts like in Windows.
the greetings text when logging into the system
DNS hosts
users and groups that can do sudo. Edit via sudo visudo.
log configuration (cron etc)
daemon control files. To remove from startup, use sudo /etc/init.d/XYZ stop, sudo update-rc.d -f XYZ remove. To start manually: sudo /etc/init.d/XYZ start
Gnome Desktop Manager.
file run at system start. Runs the files in /etc/rcX.d depending on run level
files that are run from /etc/rcS depending on run level. See The Linux Boot Process Explained
log files
lock files and run-time information
the list of URLs for apt-get for upgrading / installing packages

Also see Filesystem Hierarchy Standard.