How the Organization Works
The UNIX operating system is organized in a hierarchy of files (a data set saved under a title), starting with the "big cheese", the
root directory of the entire UNIX file system. When using UNIX, you must save all your work in a file or else you will lose the data
when you end your UNIX session. UNIX directories are files that act as "folders" to organize files and directories (called subdirectories).
They are similar to their Mac, DOS and Windows counterparts. It also sees all devices, networks and peripherals as files that can be
written to and read from.
The directory that will interest you the most is the home directory. This is your personal directory on Unix and there is one
for every person who joins the UNIX organization. This is where you will start every time you logon to a UNIX system and where you can
store your personal files. Where this file is on the system is sometimes complicated. At Stanford, the home directory of user joesmo
may be /afs/ir.stanford.edu/users/j/o/joesmo.
Another directory to be familiar with is the present working directory. This is the directory that you are presently in during your
UNIX session. Any commands you use will only affect the present working directory, unless you specify another directory.
There are many commands that allow you to move around the file system, check which directory you are in and what files there are in the
directory, view and edit files, and create links to other directories. Click here to see examples of
how to use these commands. You will read more about these commands on the "Navigating Through UNIX" page.
UNIX systems allow you to set permissions on each file that allow access to only certain users, a group of users, or all users. You can
also determine who has the permission to view, write and execute the file. You do this by assiging Acces Control Lists (ACL). There
are three types of permssions: r - read the file or directory, w - write to the file or directory, and x execute the file
or search the directory. Read access allows the user to view the file or list the files (if it's a directory). Write access grants the right
to edit, rename, delete a file. Execute allows the user to execute the file in a shell script. There are also three types of users:
b>u - the user who owns the file (usually you), g - members of the group to which the owner belongs, and o - all other
users. You can set these permissions by using chmod . Click here for
examples
[The Birth of UNIX]
[Navigating through UNIX]
[Transfering Information Through Middlemen]
[Exercising UNIX Influence at Home]
[Examples]
References]
© Tina Hsiu-man Young, Nov. 1999
