Because of the demand for copies of this doc, I'm posting it on this
newbie list. Please excuse the lack of finesse. I wrote it as sort of
a summary for own use.. Some friends read it and wanted copies. That's
why it's here.
I don't know HTML and I'm more concerned with contents than artwork..
If anyone is interested in refining it, please send me a copy. There'll
be more, Partitioning, Command Line, Issuing Commands, basic stuff for
folks who have dificulty in understanding these things as I did.. I
hope this helps someone get started.
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LINUX DIRECTORY SYSTEM
One way to get some understanding of the Linux Directory System is to
compare it to a typical office filing cabinet. We'll consider the
cabinet as the starting point or root of the office's filing system.
The filing system is divided into drawers that have labels that in some
way identify with their contents
Our special filing cabinet has an identification symbol / and its
four drawers are named 'root', 'home', 'usr', and 'etc'. Each
drawer contains folders and some documents and all these items have
labels for identification. Some folders contain additional folders and
even these may contain more folders with documents here and there. By
having an organized order to these folders and documents, we are able to
locate any document by starting with the root of the system, the
cabinet, then going to the proper drawer and opening specific folders
until we come to the desired document.
A Linux Directory System is organized much like the above cabinet. The
difference is, in Linux, we are working with electronic data storage
instead of physical data storage.
The Linux Directory System is contained in a huge directory. Think of
this huge directory as an electronic file cabinet which is the beginning
or root of the system. It contains electronic drawers which contain
electronic folders and electronic documents. Instead of calling them
cabinet, drawers, and folders, we'll call all of them directories and
instead of documents, we'll say files.
/ (the root of the system)
__________________________________|_____________________________________________
| | | |
| | | |
| | | | |
/bin /boot /dev /etc /home /usr
/mnt /proc /root /sbin /tmp /lib /var
This shows Linux's standard names of the directories that are like
drawers of a cabinet. These directories are assigned special duties
according to their names. For example, /dev contains control data for
devices such as disk drives, modems, and other hardware.
One particular directory is named /root. This is one of the
subdirectories of the root of the system labelled /. Think of it as
a cabinet having a drawer labelled 'cabinet'
/root is a special directory that is allowed to be opened by just one
person, Think of it as a drawer that has a combination lock and only one
person knows the combination. We'll call this person 'the root user',
the person in charge of the entire system.
The 'root user' is the only person who knows the password that will
open this directory called /root. The 'root user' is the only one
who is allowed to manipulate whatever important information is needed
in '/root' to make the computer do what it is supposed to do
Linux allows more than one user use its facilities. These users have
private directories that are located in the /home directory. Each
private directory is protected by a password to prevent other users
from using it.
The only other user that can access these private directories is the
user named 'root', the manager of the Linux system ,
We'll follow one trail in a directory under / --- /usr which
contains many additional directories, one of which is called /bin and
this /bin contains another directory called /control-panel..
/
__________________________________|____________________________________________
| | | |
| | | |
| | | | |
/bin /boot /dev /etc /home /usr
/mnt /proc /root /sbin /tmp /lib /var
|
_________________________________|______________________________________________
|
|
| |
| |
/bin (files)
|
______________|________________
| | | | | |
|
/ menu
|
_______________|____________________
| | | | |
Notice that the word 'bin' appears twice in the diagram.
There's a /bin directory directly under / and again under /usr.
Even though they have identical labels and contents are basically
similar, their exact contents may be different because of where they are
located. Duplicate directory names also occur in other directory
chains.
The directory path in the above example can be expressed like this:
/usr/bin/menu/
( the final / (after menu) indicates that the list is incomplete so
/menu is a directory which means that there's more to the list.
If the / is absent, the final element is a file of some kind.
There are some instances where the final directory is normally empty but
data may be entered temporarily during the execution of some command.
Some directory chains can be quite lengthy.
Linux documentation sometimes use the terms 'parent diectory' and
'child directory' when referring
to a directory that contains a subdirectory
QUIZ: (it's OK to look for the answers in the previous text)
1. What is /root?
A. The root directory
B. The starting point of the directory system.
C. A general purpose directory for any user.
D. A subdirectory of the root directory.
2. What does a Linux 'root directory' most closely resemble
in an office's file system ?
A. One of the drawers of a filing cabinet.
B. One of the folders in the drawers of a cabinet.
C. The filing cabinet.
D. One of the documents in a drawer.
3. Is a password required to access the root directory?
4. What is the user who manages the entire directory system called.?
5. Which user(s) can access the directory labelled / ?
6. Which user(s) can access the /root directory?
7. Where would you look to find the directories that contain
an ordinary user's private files?
A. The /home directory.
B. The /usr directory.
C. The /root directory.
8. In this incomplete directory chain, which of the choices is most
likely the next item in the chain?
/etc/first/second/third/fourth/
A. A directory
B. A file
C. Either a file or a directory
D. None of the above
9. In #8, what is '/third', a file or a directory?
10. True or False: The final item of a directory chain always
contains some kind of data.
11.. In this chain, /bin/cats/feeding/litterbox/, which the
following best describes /feeding
A. Both C and D
B. Neither C nor D
C. Parent directory
D. Child directory
----------------------------------------------------------------------------------------
Answer to #3 This is a trick question. When you log on to Linux, you
must supply your user name and
password. Other than that, anyone can access the root directory without
an additional password.
But, you do need a password to access /root.
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Here's a list of the various cabinet drawers that shows the general
roles that their files play.
.
/bin Essential command binaries such as certain programs.
/dev Device files such as floppy drive, CDROM, hard drive
partitions and many others
/etc Machine-local system configuration
/home User home directories
/lib Shared libraries
/mnt Mount point of devices, often used in conjunction with /dev.
/proc Process information pseudo-filesystem
/root Home directory for root user, root
/sbin Essential system binaries
/tmp Temporary files
/usr Second major hierarchy
/var Variable data
In order to make use of the Linux directory system, we must know how to
select a directory, how to look at its contents, create new
directories, copy or move data from one directory to another, add files
and many other operations. But first, we must learn about the COMMAND
LINE and then how to issue commands to do all these operations.
