- Operating System | File System Layout
- The following are the basic file systems that make up the Unix operating system. You can use the manpage command: "man hier" to review a more complete list of the file system hierarchy.
/bin (binaries) - essential system binaries
ls, cp, mv, chmod, cat, kill, gzip, and more/sbin (system binaries) - system binaries, daemons, and administrative programs.
fsck, mount, umount, adduser, shutdown, route, and more/dev
- (devices) - device files represent physical and logical devices on a unix system. Having files that represents physical devices allows for more flexible manipulation and easier notation.
- Examples of different drive devices on Solaris.
- brw-r----- 1 root sys 32, 14 Aug 4 11:51 ../../devices/iommu@f,e0000000/sbus@f,e0001000/espdma@f,400000/esp@f,800000/sd@1,0:g
/etc
- Contains many system configuration files.
- /etc/passwd - essential user information including user name, user id, group id, home directory, and shell
- /etc/shadow - encrypted password, account expiration information
- /etc/group - user/group information
- 'rc' files - system startup/shutdown scripts
- /etc/security/ - some unix flavors use this to store files relating to system security
/home (home directories) - where users store their files and do daily activity from. for the average user, this will be the most important directory they use /lib (libraries) - shared library images. Many programs rely on these. Libraries have common routines that can be used by many programs. Instead of creating new libraries for every single application, they share these. Unix library files are akin to Windows .dll files. /proc (processes) - 'proc' is a virtual file system. Files here are stored in memory, not on the drive. A user or admin can get information on programs running through the proc files. /tmp (temporary) - Many programs (and users) utilize this directory for writing files while running and remove them when done. Users with a quota (or limit on their disk space) can access this space for temporary storage. Beware! Admins like to delete stuff here when running low on diskspace. On some systems, this directory is completely erased during bootup. /var
- (various) - System subdirectories. These directories used to be part of the /usr/ filesystem. Solaris upgrades have moved these to their own world in /var.
- /var/adm - linked to /var/log in linux, 'adm' notation is used in other flavors of unix.
- /var/log - system logs that record user and system activity. Logs keep track of connections to the system, daemon activity, file transfers, mail, and more.
- /var/spool - spool dir contains incoming mail, outgoing mail, cron jobs, and more.
- /var/man - various manual pages on system binaries
/usr
- (user) - Contains a wide variety of subdirectories for user and administrative tools
- /usr/X11R6 - The X-Windows subdirectory - all X-Win programs and config files
- /usr/sbin - much like /sbin, a bulk of system admin programs are located here
- /usr/bin - much like /bin, this contains the bulk of the unix programs not found in other places
- /usr/etc - more configuration files for system utilities and programs
- /usr/include - 'include' files for the C compiler - primarily used for system programmers
- /usr/lib - more shared libraries for system applications
- /usr/man - more manual pages for system tools
- /usr/local - files not essential to the system or users, but often the home of many extra utilities that give the system a lot of its functionality. Programs like 'ssh' and 'pgp' are typically installed here by default.
