Translations by Andy Lundqvist

Linux and Unix file systems are organized in a hierarchical, tree-like structure. The highest level of the file system is the <filename>/</filename> or root directory. All other files and directories exist under the root directory. For example, <filename>/home/jebediah/cheeses.odt</filename> shows the correct full path to the <filename>cheeses.odt</filename> file that exists in the <filename>jebediah</filename> directory, which is under the <filename>home</filename> directory, which in turn is under the root (<filename>/</filename>) directory.

<filename>/boot</filename> - <emphasis>boot</emphasis> configuration files, kernels, and other files needed at <emphasis>boot</emphasis> time

<filename>/home</filename> - <emphasis>home</emphasis> directories for different users

<filename>/initrd</filename> - used when creating a customized <emphasis>initrd</emphasis> boot process

<filename>/lib</filename> - system <emphasis>lib</emphasis>raries

<filename>/lost+found</filename> - provides a <emphasis>lost+found</emphasis> system for files that exist under the root (<filename>/</filename>) directory

<filename>/media</filename> - automatically mounted (loaded) partitions on your hard drive and removable <emphasis>media</emphasis> such as CDs, digital cameras, etc.

<filename>/mnt</filename> - manually <emphasis>m</emphasis>ou<emphasis>nt</emphasis>ed filesystems on your hard drive

<filename>/opt</filename> - provides a location for <emphasis>opt</emphasis>ional (3rd party) applications to be installed

<filename>/proc</filename> - special dynamic directory that maintains information about the state of the system, including currently running <emphasis>proc</emphasis>esses

<filename>/root</filename> - <emphasis>root</emphasis> user's home directory, pronounced "slash-root"

<filename>/sbin</filename> - important <emphasis>s</emphasis>ystem <emphasis>bin</emphasis>aries

<filename>/srv</filename> - can contain files that are <emphasis>s</emphasis>e<emphasis>rv</emphasis>ed to other systems

<filename>/sys</filename> - <emphasis>sys</emphasis>tem files

<filename>/tmp</filename> - <emphasis>t</emphasis>e<emphasis>mp</emphasis>orary files

<filename>/usr</filename> - applications and files that are mostly available for all <emphasis>us</emphasis>e<emphasis>r</emphasis>s to access

<filename>/var</filename> - <emphasis>var</emphasis>iable files such as logs and databases

Permissions

All of the files on a Linux system have permissions that allow or prevent others from viewing, modifying or executing them. The superuser "root" has the ability to access any file on the system. Each file has access restrictions, user restrictions, and an owner/group association.

Every file is secured by the following three layers of permissions, in order of importance:

user

applies to the user who is the owner of the file

group

applies to the group that is associated with the file

other

applies to all other users

Inside each of the three sets of permissions are the actual permissions. The permissions, along with the way they apply differently to files and directories, are outlined below:

read

files can be displayed/opened

directory contents can be displayed

write

files can be edited or deleted

Terminal

Working at the command line is not as daunting a task as you would think. There is no special knowledge needed to use the command line as it is a program like everything else. Most things in Linux can be done using the command line. Although there are graphical tools for most programs, sometimes they are just not enough. This is where the command line comes in handy.

The terminal is often called the command prompt or the shell. In days gone by, this was the way the user interacted with the computer; however, Linux users have found that the use of the shell can be quicker than a graphical method and still holds some merit today. Here you will learn how to use the terminal.

The original use of the terminal was as a file browser, and indeed it is still used as a file browser. You can use the terminal as a file browser to navigate your files and undo the changes that have been made.

Starting the Terminal

The <application>Konsole</application> can be started by choosing <menuchoice><guimenu>K-menu</guimenu><guimenuitem>System</guimenuitem><guimenuitem>Konsole (Terminal Program)</guimenuitem></menuchoice> from the Desktop menu system.

Common Commands

View Directories: - ls

The <application>ls</application> (LiSt) lists files in different colors with full formatted text

Create Directories: - mkdir (directory name)

The <application>mkdir</application> (MaKeDIRectory) command will create a directory.

Change Directories: - cd (/directory/location)

The <application>cd</application> (Change Directory) command will change from your current directory to any directory you specify.

Copy Files/Directories: - cp (file or directory name) (to directory or filename)

The <application>cp</application> (CoPy) command will copy any files you specify. The <application>cp -r</application> command will copy any directories you specify.

Remove Files/Directories: - rm (file or directory name)

The <application>rm</application> (ReMove) command will delete any filename you specify. The <application>rm -r</application> command will remove any directory you specify, and all its contents.

Move/Rename Files/Directories: - mv (file or directory name)