common unix directories
/ - the root of the entire filesystem
/etc - contains system configuration files
/home - contains home directories of all users
/local - a disk partition local to each machine, which users are welcome to use for temporary storage. Files in /local do not get backed up.
/tmp - one of the system's places for temporary files. Files in /tmp usually get wiped out on reboot.
/usr - contains system software
/var - contains system stuff, like mail, log and accounting files,and printing spool directories
/var/mail - system mail directory (on allspice)
various command (binary) directories
binaries are executable files written in machine language (binary)
/usr/bin, /bin - standard user binaries (such as ls, chmod, sh...)
/usr/sbin, /sbin - system binaries (such as tar, link ...)
/usr/local/bin - locally added software binaries (such as diff, emacs, netscape ...)
/usr/swat/bin - locally created commands (such as list-users ...)
/usr/X11R6/bin - X11 binaries