/sbin
binaries essential to system and all users/usr/sbin/
system admins binaries/bin
binaries used by system and all users. cannot do without them./usr/bin/
non essential users binaries/etc
config file for system eg: /etc/init.d/ has startup config scripts/home
each user gets a directory in here/root
home directory of root user/lib
shared libraries required by system programs (kind of like windows .dll files)/var
spooling data, stuff always being written to and read from it