Linux basics Chap2

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Use the Linux Desktop

Version 2 Copyright © 2007 Novell, Inc. Copying or distributing all or part of this manual is protected by 2-1 a Creative Commons Attribution-NonCommercial-ShareAlike 2.5 license.

S E C T I O N 2 Use the Linux Desktop

This section gives an overview of two different graphical userinterfaces of SLES and explains how to access the command line.

Objectives

1. Overview of the Linux Desktop

2. Use the KDE Desktop Environment

3. Use the Gnome Desktop Environment4. Access the Command Line Interface From the Desktop



2-2 Copyright © 2007 Novell, Inc. Copying or distributing all or part of this manual is protected by Version 2a Creative Commons Attribution-NonCommercial-ShareAlike 2.5 license.

Getting Started with Linux: Novell’s Guide to CompTIA’s Linux+

Introduction

You cannot install Microsoft Windows without its graphical userinterface (GUI). However, in Linux, the GUI is a normal applicationthat you can choose whether or not to install.

You can configure most services in Linux by editing an ASCII textfile, so you do not need a GUI if you want your computer to act

only as a server.

While a GUI is convenient, not installing a GUI has the followingadvantages:

■ Stability. Every program contains errors that can make yoursystem unstable. The fewer programs are installed, the morestable your system will be. A graphical user front end is a large

program that might contain a large number of undiscoveredprogramming errors, even if the error ratio is low.

■ Performance. Every running program needs system resources.Fewer programs running on your computer means increasedperformance.

■ Security . The points mentioned under Stability above are also

relevant from a security perspective. The fewer programsinstalled, the fewer the potential security vulnerabilities thereare. You need not worry about the vulnerabilities of programsyou have not installed on you system.





Objective 1 Overview of the Linux Desktop

The base of any GUI on Linux is the X Window System (simplycalled X or X11). It allows you to control the input and output of several applications in different windows of a graphical interface.

You need to distinguish here between graphical applications, whichrun in their own windows, and text-based applications, which are

carried out in a terminal window.The X Window System was created in 1984 at MassachusettsInstitute of Technology . The aim of the development was to beable to use graphical applications across a network, independent of hardware.

The X Window System allows graphical applications to bedisplayed and operated on any monitor, without running theapplications on the machines to which these monitors areconnected.

The basis for this is the separation into a server component (Xserver) and the application itself (client application). The X serverand client application communicate with each other by way of

various communication channels.■ X server. The X server controls the graphical screen. This

corresponds roughly to what would be called a graphics driveron other systems. In addition, it manages the input devices,such as keyboard and mouse, and transmits their actions to theX client.

The X server, however, has nothing to do with the appearanceof the window and the desktop; this is the task of the windowmanager. XFree86 3.3.x and its successor XFree86 4.x are freeimplementations of the X server. SUSE LINUX EnterpriseServer defaults to using XFree86 4. x .





■ Client application. The client application is a graphical

application that uses the services of the X server to receivekeyboard and mouse actions and to have its own outputdisplayed on the screen.

As shown in the following figure, the X server is running oncomputer da5 , while the X client applications are running oncomputers da1 and da2 :

Figure 2-1

The display of the client applications, however, is performed by theX server on the machine da5 . All of these computers can be runningdifferent operating systems.

xThe communication between X server and X client uses the network protocol

TCP/IP—even if the server and client run on the same computer.

Window managers are specialized client applications. A windowmanager works together with the X server and provides additionalfunctionality. The window manager

■ Provides control elements





■ Manages virtual desktops

■ Provides functionality of window frames (for example,changing their size)

The X Window System is not linked to any specific windowmanager and thus it is not linked to any particular look and feel.

The current version of SLES 9 has several window managers,

including kwin (the KDE window manager), the GNOME windowmanager, and twm (Tab Window Manager).

Desktop environments go far beyond the look and feel windowmanagers provide for desktops and manipulating windows. The aimis to provide clients with a unified look and feel. KDE is thestandard graphical desktop for SLES 9, but you can install the

GNOME desktop instead.





Objective 2 Use the KDE Desktop Environment

One of the most frequently used graphical desktop environments isKDE. This desktop environment is installed by default during theinstallation of SLES 9.

The following explains how to use KDE on SLES 9:

■ How to Log In

■ How to Log Out

■ How to Shut Down and Reboot the Linux System

■ How to Identify KDE Desktop Components

■ How to Manage Icons in the KDE Environment

■ How to Use the Konqueror File Manager

How to Log In

If computer users want to work with a multiuser operating system,they must first identify themselves to the operating system. For thispurpose, they need

■ A login string or username

■ A password (usually assigned by the system administratorwhen a new user is added)





When the computer is booted and ready for work, the following

login dialog appears:

Figure 2-2





After entering a username and password, select Login . If the login

is successful, the following KDE desktop environment appears, aswell as a welcome screen and some useful tips:

Figure 2-3

You can read the information or just close the window by selectingthe X button in the top right corner of the window:

Figure 2-4





How to Log Out

When you are ready to log out of the system, open the KDE menuby selecting the first (left) icon in the bottom panel:

Figure 2-5

At the bottom of the KDE menu, select Logout . You can also

right-click on the window background and select the same optionfrom the popup menu.

After selecting Logout, a confirmation dialog appears. If you selectLogout again, you are logged out and the login screen reappears,allowing you or another person to log in.

How to Shut Down and Reboot the Linux System

If you are at the login screen, you can open the Menu menu youselect from several choices, including the following:





■ Session Type. You can choose a window manager other than

KDE. In this manual, we cover only KDE (the default windowmanager).

■ Restart X Server. You can restart the program that isresponsible for the GUI. Remember, SLES 9 does not need aGUI to work.

The GUI is clearly separated from the operating system.

However, in this course we work from the GUI interface.■ Shutdown Type. If you select this option, you are asked if you

want to shut down or restart your computer:

Figure 2-6

For security reasons, you have to enter the root passwordbecause only root is allowed to restart or shut down thecomputer.

If you select Turn Off Computer and select OK , Linux closesall the (system) programs currently running.

Older computers that do not have power management andcannot switch themselves off can be switched off manuallywhen the following message appears:

If you switch the machine off too soon, this could possibly leadto loss of data.

Master Resource Control: runlevel 0 has been reached





x You should always shut down your computer before you turn it off.

How to Identify KDE Desktop Components

After you log in, your system will by default start the KDE desktopenvironment. It is composed of

■ The Desktop

■ The KDE Control Panel (Kicker)

■ The KDE Menu

■ Virtual Desktops

The Desktop

The desktop shows only a few icons. You can start the applicationsassociated with these icons by selecting them once with the leftmouse button.

You can move the icons by dragging them with the mouse.

The KDE Control Panel (Kicker)

You control the KDE desktop by using the KDE control panel (alsocalled the Kicker), located at the bottom of the desktop:

Figure 2-7

The following are the most commonly used icons and theirfunctions (from left to right):





■ Green button with red “N”. Menu of all configured programs

and functions (not of all programs and functions installed on themachine). This menu is called the KDE menu .

■ Blue house. Konqueror, the preferred KDE file manager.

■ Shell in front of monitor. A terminal window in which to typecommands directly.

■ Lifesaver with a chameleon head. The SUSE Help Center.

■ Globe with gear wheel teeth. Konqueror, as preferred KDEWeb browser.

■ “E” with letter. The KMail email program.

■ The white and gray box. Virtual desktops.

■ The empty area right of the virtual desktops. Task Manager

area.■ Clipboard with “k”. Clipboard.

■ Loudspeaker. A sound mixer.

■ Sheet with “i”. SuSEwatcher for automatic updates.

■ Computer card. SuSEplugger for plug and play.

■ Clock. Current time.





The KDE Menu

Programs are normally started from the KDE menu. You can selectthe KDE menu button to open the KDE menu:

Figure 2-8

This menu consists of the following three sections:

■ Most Frequently Used Applications. As indicated by thename, this section lists the five most frequently usedapplications. Accordingly, the listed entries can change fromtime to time.

■ All Applications. This section features an overview of variousapplications sorted by subjects (such as Multimedia ).

■ Actions. This section provides a command line interface, anoverview of the bookmarks, an option for locking the screen,and the option for logging out.





A submenu in the KDE menu is marked by a small black arrow in

the right-hand corner. To open a submenu, move the mouse cursorover the menu entry. To start a program, select the correspondingentry once with the left mouse button.

Virtual Desktops

If you are working with several programs concurrently, the screencan quickly become cluttered with open windows. In Linux, youcan bring order to this chaos by changing to another (virtual)desktop. You can switch between the various desktops via thecontrol panel.

By default, two virtual desktops are configured. In the KDE controlcenter, you can increase the number of usable virtual desktops up tosixteen. Every virtual desktop can host a virtually unlimited numberof applications. Using these virtual desktops, you can easilyorganize your work.

How to Manage Icons in the KDE Environment

Three areas in your KDE environment contain icons:

■ Desktop

■ Kicker

■ KDE Menu





Desktop

There are several ways to create a new icon on your desktop;however, for simplicity, only one method is used in this course.

To create an icon for an application on your desktop, do thefollowing:

1. Select the item in your KDE menu.

2. Hold down the left mouse button, move the mouse pointer to freespace on your desktop and release the mouse button.

3. In the menu that appears, select Copy Here .

Kicker

You can add new programs to the control panel by right-clicking afree area of the panel and then selecting Add .

You can remove a program from the control panel by right-clickingits icon in the control panel and then selecting Remove program

name .

You can move icons in the panel by holding down the middlemouse button or by choosing Move from the Context menu.

KDE Menu

To make changes in your KDE menu, do the following:

1. Start the KDE Menu Editor by selecting the KDE menu icon withthe right mouse button and selecting Menu Editor .





The following dialog appears, where you can edit the KDE

menu:Figure 2-9





How to Use the Konqueror File Manager

You can do nearly all work on the file system by using the KDEKonqueror program. To start Konqueror, select the blue house iconin Kicker. The following appears:

Figure 2-10

To navigate quickly through the file system, activate the navigation panel (select Window > Show Navigator Panel ), which splits themain window and displays the directory tree.

The icon with the blue house on the navigation panel displays thedirectory tree starting from the user's home directory. The icon withthe folder displays the directory tree starting from the root directory.





The Konqueror window is divided into three sections:

Figure 2-11

■ The Top section contains a menu bar, a toolbar, and an addresspanel. The bar to the left is the preset navigation panel, whichserves primarily for navigation and orientation.

■ After you select the blue house or folder icon, the navigationarea is split into a Left window and a right window. You canuse the left window for quicker navigation through the file

system tree.■ The Right window displays the contents of the directory you

selected in the left window. This is the file view.

U h Li D k





There are several ways to navigate in the file system: using three

arrows on the left side of the toolbar is the simplest way. Thecurrent position can be seen in the text window of the URL panel(in the above example, /home/tux/ ).

If you select the arrow pointing up, you will move from the currentdirectory to the next highest directory (from /home/tux/ to /home/ ).The arrow pointing to the left returns you to the previously visitedlocation. You can move forward again with the right arrow.

■ You can open a directory and view its contents by selecting thedirectory in the file view. If you select a normal file, KDE triesto open it or starts a program to open it.

■ Selecting the house symbol in the toolbar takes you directly toyour own home directory (for example, /home/tux/ ).

■ If you select a directory in the navigation area, its contents aredisplayed in the file view.

You can double-click the directory in the navigation area to open itand view all subdirectories in it. Double-click the directory again toclose it.

x If you prefer a detailed list that displays information about each file in thetree, activate the tree view by selecting the second icon from the right in thetoolbar.






Exercise 2-1 Explore Your KDE Desktop

It is possible to administer SLES9 without a graphical userinterface. However, sometimes a GUI is much more convenientthan a pure text console. The purpose of this exercise is tofamiliarize you with KDE.

To explore your KDE desktop, do the following from the GUI loginscreen (where you were left after installing SLES 9):

1. In the Username field, enter geeko .

2. In the Password field, enter N0v3ll (use a zero, not an uppercaseO).

For security reasons, asterisks are displayed instead of theactual letters when you enter the password.

3. Select Login .

The KDE desktop environment starts, and initial dialogs appear.

4. Close the SUSE LINUX welcome screen and the Kandolf’sUseful Tips dialog by selecting the X in the upper right corner of the windows.

5. (Conditional) If a new hardware dialog appears, deselect KeepMe Informed about New Hardware ; then select No .

6. Start the file manager Konqueror by selecting the blue houseicon in Kicker.

7. View the navigation area by selecting the red folder icon on theleft side of the Konqueror window.

8. View the contents of the /etc/ directory by selecting etc in theside panel (a single mouse click).

9. Copy the file /etc/DIR_COLORS to the directory /tmp/ byscrolling down and selecting the DIR_COLORS file icon,dragging it over the tmp folder icon in the navigation area, andreleasing the mouse button.

10. From the popup menu, select Copy Here .






11. View the contents of the directory /tmp/ by selecting tmp in the

side panel (a single mouse click).12. Rename the copied file by right-clicking the DIR_COLORS file

icon, and then selecting Rename from the popup menu.

13. For the new filename, type example.txt ; then press Enter .

14. Quit Konqueror by selecting the X button in the top right cornerof the window.

15. Open the KDE menu by selecting the leftmost icon in the bottompanel.

16. Select Logout ; then select Logout again.

You are returned to the GUI login screen.

17. Open the Menu drop-down list; then select Shutdown .

18. Select Restart computer ; then enter the root password novell inthe Password field and select OK .

After the computer has restarted, the login screen appears.

19. Log in as geeko with a password of N0v3ll ; then select Login .

20. Close all windows that open automatically by selecting the X

button in the top right corner of the window.

(End of Exercise)





Getting Started with Linux: Novell s Guide to CompTIA s Linux

Objective 3 Use the Gnome Desktop Environment

Both GNOME and KDE are comfortable desktop environments.Like KDE, GNOME supports drag and drop. Numerous programsare specifically designed for GNOME.

To use the GNOME desktop environment, you need to know thefollowing:

■ How to Start GNOME■ How to Navigate in GNOME

■ How to Manage Icons in GNOME

■ How to Use the GNOME File Manager (Nautilus)




p


How to Start GNOME

Before you select Login at the login screen, you can start GNOMEinstead of KDE by selecting Session Type > GNOME from theMenu drop-down list. The following appears:

Figure 2-12

How to Navigate in GNOME

Besides the main window, the GNOME desktop includes thefollowing two panels:

■ Top panel. The panel at the top of the desktop is responsiblefor launching applications. The following features are available(left to the right):





❑ Applications menu for launching applications

❑ Actions menu for basic actions (such as logging out)❑ The Nautilus file manager (house icon)❑ The terminal emulation window (monitor icon)❑ A clock ❑ A speaker icon for volume❑ A menu listing all open windows

■ Bottom panel. The panel at the bottom of the desktop providesthe following:❑ An icon to close all open windows❑ A task manager❑ A pager for the 4 virtual desktops

You can start a program with an icon on the desktop bydouble-clicking the icon. You can set preferences for the desktopenvironment by selecting the Start Here icon.

To quit GNOME, select Actions > Log Out in the GNOME panel.The following appears:

Figure 2-13

If you select Save Current Setup , your current desktopenvironment settings are saved.





How to Manage Icons in GNOME

You can find icons in the following three areas on your desktop:

■ Desktop

■ Panel

■ Application Menu

Desktop

There are several ways to create a new icon on your desktop;however, in this course only one method is described.

To create an icon for an application on your desktop, select the itemin your Applications menu, drag it to a free space on your desktop,release the mouse button; then select Copy Here .

Panel

You can add new programs to the control panel by right-clicking afree area of the panel and then selecting Add to Panel . From thesubmenus displayed, select the application you want to add.

You can remove a program from the control panel by right-clickingits icon in the control panel and then selecting Remove from Panel .

You can move icons in the panel by holding down the right mousebutton and selecting Move from the context menu.

Application Menu

To add an entry to a menu, do the following:

1. Double-click the Start Here icon on the desktop.

The Start Here location appears.





2. In the file manager window, double-click the icon that representsthe menu ( Applications or Menu SuSE ) to which you want toadd the launcher.

3. Select File > Create Launcher .

A Create Launcher dialog is displayed.

4. Enter the properties of the launcher in the Create Launcherdialog; then select OK .

How to Use the GNOME File Manager (Nautilus)

GNOME provides its own file manager, called Nautilus, shownbelow:

Figure 2-14





You can start Nautilus by selecting the house icon in the top panelor by selecting the username Home icon on the desktop. AlthoughNautilus does not provide as many features as some other filemanagers, it has the features you need for most file navigation tasks.

To display the file system tree view, select View > Side Panel ; thenselect Tree from the side panel drop-down list. A window similar tothe following appears:

Figure 2-15





Exercise 2-2 Explore Your GNOME Desktop

Whether you use KDE or GNOME is entirely a matter of personalpreference. The purpose of this exercise is to familiarize you withthe GNOME desktop.

To explore your GNOME desktop, do the following:

1. From the KDE menu, log out as geeko by selecting Logout >Logout .

2. From the GUI login screen, select the Menu drop-down list; thenselect Session Type > GNOME .

3. Log in as geeko with a password of N0v3ll (select Login ).

The GNOME desktop environment starts.

4. From the GNOME desktop, select the Applications menu (toppanel) and view the applications available.

5. Start the Nautilus file manager by selecting the house icon in thetop panel.

6. Display the side pane by selecting View > Side Pane .

7. View the file system tree in the side pane by selecting Tree from

the drop-down list at the top of the side pane.8. Display the contents of the directory /tmp/ by expanding

Filesystem ; then select tmp .

9. Delete the file example.txt by right-clicking the file icon andselecting Move to Trash .

10. Close the Nautilus file manager window.

11. From the top of the Gnome desktop, select the Actions menu;then select Log Out .

12. Select OK .

You are returned to the GUI login screen.

13. From the Menu drop-down list, select Session Type > KDE .





14. Log in as geeko with a password of N0v3ll (select Login ).

(End of Exercise)

Objective 4 Access the Command Line Interface Fromthe Desktop

You can implement classic multiuser environment by connectingseveral terminals (dialog stations)—monitor and keyboard units—tothe serial interface of a single computer.

You can also connect several terminals to the serial interface in aLinux system. However, because in general not more than oneperson sits in front of one computer at any given time, usually onlyone physical keyboard is needed. Virtual terminals were created inLinux to allow a user to run tasks in parallel.

With virtual terminals, you can work in Linux as if you had severalclassic terminals available at the same time.

By default, you have six virtual terminals (F1–F6) running on your

computer. By pressing Ctrl + Alt + F x , you can switch betweenindividual terminals. By pressing Ctrl + Alt + F7 , you can switchback to your graphical user interface.

You can determine the terminal currently being used from the ttynumber (tty1–tty6). tty is an abbreviation for teletype , which isanother word for terminal.

When you switch to a virtual terminal, a login prompt appears:

Welcome to SUSE LINUX Enterprise Server 9 (i586) - Kernel 2.6.4-27-default(tty1).

da10 login:





From here you can enter your login name and password. To log outenter exit .

x The file /etc/issue contains the text that is displayed before you log in to thesystem (see above). When you log in to a host via the network, the contentsof the file /etc/issue.net are used.

To display a welcome message after the successful login to the system, youcan enter the text in the file /etc/motd with the help of a text editor such as vi.

Besides using the virtual terminals, you can start a terminalemulation (called Konsole) from your KDE desktop Kicker byselecting the following icon:

Figure 2-16

The terminal opens inside a window with options you can select tomodify the display of the terminal (such as font and backgroundcolor).





Exercise 2-3 Access the Command Line Interface

As has been stated before, SLES9 does not need a GUI for itsadministration. And even with a graphical desktop environmentrunning you can switch to the text consoles any time if you like to.This exercise shows you how.

To access the command line interface, do the following:

1. Switch to the first virtual terminal by pressing Ctrl + Alt + F1 .

2. (Conditional) If you see a SUSE - A Novell Company splashscreen, display the command line by pressing F2 .

3. Enter geeko as a login name.

4. Enter N0v3ll as the password.

5. Switch to the second virtual terminal by pressing Ctrl + Alt + F2 .

Notice that you are not logged in at this terminal.

6. Press Ctrl + Alt + F1 to switch back to the first terminal.

You are still logged in as geeko.

7. Log out by entering exit .

8. Switch back to the graphical user interface by pressing Ctrl + Alt+ F7 .

(End of Exercise)





Summary

Objective Summary

1. Overview of the Linux Desktop The X Window System consists ofa server component (X server)and client applications.

2. Use the KDE Desktop

Environment

You can use the KDE to

■ Safely bring your Linux systemup and shut it down.

■ Log in and log out of the KDEsystem.

■ Manage files and directories.

3. Use the Gnome DesktopEnvironment

You can use GNOME to

■ Log in and log out of the system.■ Manage files and directories.

4. Access the Command LineInterface From the Desktop

SUSE LINUX Enterprise Serverprovides the user with six virtualterminals.

You can use the key combinationsCtrl + Alt + F1 to Ctrl + Alt + F6to switch between the individualterminals.

You can switch back to yourgraphical user interface bypressing Ctrl + Alt + F7 .

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Linux basics Chap2