Linux keeps files in a single hierarchical directory structure, that (behind the scenes) is made up of a combination of hard drives, CD-ROMs, floppy disks, ZIP drives, etc.
The typical Linux filesystem looks like this:
/
|- bin Essential programs (or binaries)
|- boot Startup (or boot) information
|- dev Devices
|- etc Configuration files
|- home Users' home directories
| |- user1
| |- user2
| |- user3
|
|- lib System libraries and other various program files
|- lost+found Files recovered after filesystem checks
|- mnt Mount point for removable disks
| |- cdrom (An alternative is /cdrom and /floppy)
| |- floppy
|
|- proc A special directory with file-based system information
|- root Home directory for the root user
|- sbin Essential system programs
|- tmp Temporary work space
|- usr
| |- X11R6 X-Windows files
| | |- bin X-Windows programs
| | |- include
| | |- lib
| | |- man
| | |- share
| |
| |- bin General programs
| |- dict Dictionary
| |- doc Documentation
| |
| |- etc Additional configuration files
| |- include Include files for the C preprocessor
| |- info GNU info files
| |- lib Additional libraries
| |- local Files generally not supplied by the distribution
| | |- bin
| | |- doc
| | |- etc
| | |- include
| | |- lib
| | |- man
| | |- sbin
| | |- share
| |
| |- man Man (ie. user manual) pages
| |- share Files that can be shared between computers of different architectures
| |- sbin Additional system programs
| |- src Source code directories (eg. /usr/src/linux/)
|
|- var
|- lock Lock files
|- log Log files (system messages, error logs, etc.)
|- spool Spool files
|- mail Users' mailbox files