A practical guide to Fedora and Red Hat Enterprise Linux, 7th Edition (2014)

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The Settings window has the following items:

• Background—Sets the desktop background. For more information refer to “Desktop Background” on page 109.

• Notifications—Specifies which applications display notifications and how much information each includes in pop-ups.

• Online Accounts—Adds credentials for Google, Facebook, and other accounts to be stored securely by the system.

• Privacy—Controls automatic screen lock, how you appear on the desktop and network, recent usage and history, and how often trash and temporary files are purged.

• Region & Language—Specifies language, format, and input sources.

• Search—Specifies which applications are consulted when you use the Search text box in the Activities Overview screen (page 92).

• Bluetooth—Controls Bluetooth adapters.

• Color—Specifies a color profile for a monitor.

• Displays—Configures display (monitor) resolution. Refer to “Displays,” next page.

• Keyboard—Controls whether and how keys repeat, cursor blinking, and keyboard shortcuts.

• Mouse & Touchpad—Switches between right- and left-handed mouse, and controls double-click and pointer speed. For more information refer to “Mouse & Touchpad” on page 110.

• Network—Displays the Settings window that controls network connections and operation. See page 638 for information on connecting to a Wi-Fi network and page 639 for general information on this window.

• Power—Controls when GNOME blanks the screen and how long the system must be idle before it is suspended.

• Printers—Adds, removes, and configures printers. See Chapter 13.

• Sound—Controls sound volume, balance, profile, and effects. On systems with more than one sound device, choose which device to use.

• Wacom Tablet—Sets up a tablet.

• Date & Time—Turns NTP (Network Time Protocol; sets/maintains the system clock automatically) on and off, sets the system date, time, and time zone, and causes GNOME to display a 12- or 24-hour clock. For more information refer to “Date & Time” on page 110.

• Details—Displays hardware and software information, specifies default applications, and tells the system what to do when it detects removable media.

• Sharing—Turns remote access via ssh (Chapter 18) on and off, and specifies which content you share.

• Universal Access—Changes settings to help you use the desktop more easily. Tabs allow you to control seeing, hearing, typing, and mouse (pointing and clicking) features.

• Users—Adds, removes, and sets up users. For more information refer to “Users: Changing Your Account Type and Password (GUI)” on page 112.

Desktop Background

The Background window (Figure 4-13) enables you to change the desktop background. To display this window, click Background in the Settings window (Figure 4-12, page 107) or right-click anywhere on an empty space on the desktop and select Change Background. Initially this window displays a picture of the current desktop background. Click that picture to display the Select Background window.

Figure 4-13 The Background window

Three buttons labeled Wallpapers, Pictures, and Colors appear at the top of the Select Background Window. Click one of these buttons, click to highlight a desktop background from those displayed, and click Select to change the desktop background to the highlighted one. The Background window reappears; click X to close the window or click the back arrow to return to the Settings window.

Several utilities and applications allow you to select a picture to use as the desktop background. For example, when you select Set as Wallpaper from an picture’s context (right-click) menu in a Nautilus File Browser window, GNOME sets that picture as the desktop background.

Displays

Most of the time the monitor attached to the system just works: Fedora/RHEL probes the monitor and autoconfigures X.org to work properly. This section explains how to configure the display in case you need to. The Displays window (Figure 4-14) configures the monitor. Check the specifications for the monitor and select the appropriate resolution value from the drop-down list. With multiple monitors, this window allows you to drag monitors to change their relative positions. Click Apply confirm the changes you have made.

Figure 4-14 The Displays window

Mouse & Touchpad

The Mouse & Touchpad window (Figure 4-15) enables you to change the characteristics of the mouse (and touchpad if there is one). To display this window, click Mouse & Touchpad in the Settings window (Figure 4-12, page 107).

Figure 4-15 The Mouse & Touchpad window

Left-handed mouse

To change the orientation of the mouse buttons for use by a left-handed person, click the radio button labeled Left. If you change the setup of the mouse buttons, remember to reinterpret the descriptions in this book accordingly. That is, when this book asks you to click the left button or does not specify a button to click, click the right button, and vice versa. See page 463 for instructions on remapping mouse buttons from the command line.

Double-click timeout

Use the slider labeled Double-click to change the speed with which you must double-click a mouse button to have the system recognize your action as a double-click rather than as two single clicks. You can control the mouse pointer speed using the slider labeled Pointer speed. Click Test Your Settings to experiment with the mouse settings. Click X to close the window or click the back arrow to return to the Settings window.

Date & Time

The Date & Time window (Figure 4-16) allows you to specify a date format (a 12- or 24-hour clock), specify a time zone (region), and turn NTP (Network Time Protocol) on or off. To display this window, click Date & Time in the Settings window (Figure 4-12, page 107) or click the time at the top of the screen and select Date & Time Settings. You must unlock this window to make changes other than changing the date format; see the tip on page 107.

Figure 4-16 The Date & Time window

Turning NTP on causes the system to set and maintain its clock from network time servers. When NTP is off, you can use this window to set the system clock manually. To specify a time zone, click a city in the local time zone; GNOME displays the name of the city in the spin box labeledCity. Alternately, you can use the spin boxes labeled Region and City to specify a city. Click X to close the window or click the back arrow to return to the Settings window.

Users: Changing Your Account Type and Password (GUI)

See “Password Security” on page 136 for help selecting a more secure password for your account. See page 137 for instructions on changing your password from the command line.

The Users window (Figure 4-17) allows you to add and remove users and change the characteristics of a user, including changing the user’s password and making the user an administrator (page 422). To display this window, click Users in the Settings window (Figure 4-12, page 107). You must unlock this window to make changes other than changing your own password or language; see the tip on page 107.

Figure 4-17 The Users window

To change your password click the text box labeled Password; GNOME displays a new window. The first item you must enter in this window is your current (old) password. The system verifies this password to ensure that an unauthorized user is not trying to alter your password. There are also text boxes where you enter and verify the new password. When you have entered a strong enough password the same way two times the system allows you to click Change. When you successfully change your password, you change the way you log in. If you forget your password, a user running with root privileges can change it and tell you the new password. Click X to close the window or click the back arrow to return to the Settings window.

Getting Help

Linux provides help in many forms and formats. This section describes how to get help while using a GUI. See page 128 for resources that are available from the command line.

The GNOME Help Window

The GNOME Help window (Figure 4-18) is displayed by yelp (projects.gnome.org/yelp) and provides information on using Linux in a graphical environment. Open this window by giving the command yelp from a Search text box (SUPER), an Enter a Command window (ALT-F2), or a terminal emulator.

Figure 4-18 The GNOME Help window

Click a topic in this window to display information on that topic. You can also enter text to search for in the text box at the top of the window and then press RETURN. In addition, most Application menus (page 98) provide a Help selection.

Using the Internet to Get Help

The Internet provides many helpful sites related to Linux. Aside from sites that offer various forms of documentation, you can enter an error message from a program you are having a problem with in a search engine such as Google (www.google.com). The search will likely yield a post concerning your problem and suggestions about how to solve it. See Figure 4-19.

Figure 4-19 Google reporting on an error message

Fedora/Red Hat Web sites

The Red Hat and Fedora Web sites are rich sources of information. The following list identifies locations that may be of interest:

• Fedora documentation is available at docs.fedoraproject.org.

• A list of all methods of getting help using Fedora is available at fedoraproject.org/wiki/Communicating_and_getting_help.

• A useful site that answers questions is ask.fedoraproject.org.

• Manuals and other documentation for RHEL are available at access.redhat.com/site/documentation and access.redhat.com.

• Various types of support documents and support are available at www.redhat.com/support (requires free registration).

• You can query the Red Hat Knowledgebase at access.redhat.com/site (requires free registration).

• The home pages for Fedora (fedoraproject.org) and RHEL (www.redhat.com) have a wealth of information.

• Fedora/RHEL support forums are online discussions about any issues people want to raise. One forum is dedicated to new users; others to Apache, the X Window System, and so on. Visit www.redhat.com/mailman/listinfo and admin.fedoraproject.org/mailman/listinfo to browse the lists.

• The Fedora/RHEL bugs database is available at bugzilla.redhat.com. Anyone can search the database. To submit new bugs or append to existing bugs, you need to sign up for a free account.

• You can find community-sourced solutions to common problems at fedorasolved.org.

• Fedora Magazine is available at fedoramagazine.org.

• RHEL hardware help is available from the Red Hat hardware catalog at hardware.redhat.com. The hardware that Fedora supports is mostly a superset of that supported by RHEL.

GNU

GNU manuals are available at www.gnu.org/manual. In addition, you can visit the GNU home page (www.gnu.org) to obtain other documentation and GNU resources. Many of the GNU pages and resources are available in a variety of languages.

The Linux Documentation Project

The Linux Documentation Project (www.tldp.org; Figure 4-20), which has been around for almost as long as Linux, houses a complete collection of guides, HOWTOs, FAQs, man pages, and Linux magazines. The home page is available in English, Portuguese (Brazilian), Spanish, Italian, Korean, and French. It is easy to use and supports local text searches. This site also provides a complete set of links you can use to find almost anything you want related to Linux (click Links in the Search box or go to www.tldp.org/links). The links page includes sections on general information, events, getting started, user groups, mailing lists, and newsgroups, with each section containing many subsections.

Figure 4-20 The Linux Documentation Project home page

HOWTOs

A HOWTO document explains in detail how to do something related to Linux—from setting up a specialized piece of hardware to performing a system administration task to setting up specific networking software. Mini-HOWTOs offer shorter explanations.

The Linux Documentation Project site houses most HOWTO and mini-HOWTO documents. Use a Web browser to visit www.tldp.org, click HOWTOs, and pick the index you want to use to find a HOWTO or mini-HOWTO. You can also use the LDP search feature on its home page to find HOWTOs and other documents.

Updating, Installing, and Removing Software Packages

Software comes in packages that include all necessary files, instructions so a program can automatically install and remove the software, and a list of other packages the package depends on. There are many ways to search for and install software packages. GNOME notifies you each time updates are available for software on the system. The Software window (Figure 4-22) provides an easy way to install software. Chapter 12 explains how to work with software packages from the command line.

Updating Software

Systems connected to the Internet are set up to search daily for software updates and notify you when updates are available. GNOME displays the message Important software updates are available in a pop-up notification window and places a notification indicator (an envelope icon) toward the right end of the Top panel when updates are available. Clicking Install updates in this window opens the Software Update window (Figure 4-21). You can open this window manually by selecting the Software Update icon from the GNOME 3 desktop Applications Overview screen (page 93) or by giving the command gpk-update-viewer from an Enter a Command window (ALT-F2) or a terminal emulator.

Figure 4-21 The Software Update window

Software Update window

When the Software Update window opens, it displays the message Checking for updates; after it finishes checking it displays the number of available updates. If no updates are available, it displays All software is up to date.

If updates are available, click Install Updates. As it downloads and installs the software packages, the Software Update window displays messages and a progress bar. If the updates require you to reboot the system or log off, the Software Update window prompts you to do so.

Software Update Preferences window

You can control how often the system checks for updates and which sources it checks from the Software Update Preferences window. Open this window by giving the command gpk-prefs from an Enter a Command window (ALT-F2) or a terminal emulator.

Adding and Removing Software

The Software window (Figure 4-22) allows you to add and remove applications from the system. Open this window by giving the command gpk-application from an Enter a Command window (ALT-F2) or a terminal emulator. Maximizing this window might make it easier to use. See page534 for instructions on adding and removing software on the command line.

Figure 4-22 The Software window

Enter the name or part of the name of an application in the text box at the upper-left corner of the window and press RETURN to search for that application. The Software window displays a list of matching software packages in the frame on the right side of the window. Alternately, you can select one of the entries from the list on the left side of the window to display a list of related packages.

Scroll through the packages displayed in the frame on the right side of the window. When you click/highlight an application, the window displays a summary of the application in the frame at the lower-right corner of the window. Put a tick in the check box next to each application you want to install. Remove ticks from applications you want to remove. Click Apply Changes to implement the changes you have marked. If a package you want to install depends on other packages that are not installed, gpk-application will ask for permission to install the dependent packages. Because you need to work with root privileges to install and remove software, the utility might ask for the root password. When it is finished, the utility might ask if you want to run the new application. Close the Software window when you are finished.

Installing Different Desktop Environments

If you are installing a new Fedora system you can download a spin to install a system with a desktop environment other than GNOME. See page 35 for a list of popular spins. On a system that is already set up, you can use yum to download and install the packages necessary to run a different desktop. When more than one desktop is installed on a system, the Password screen displays the Sessions menu (Figure 4-4, page 96) so you can choose which desktop you want to run. The following commands, which must be run from a terminal emulator and prompt for the root password, install package groups that include all necessary packages for each desktop.

Xfce

The following command installs the Xfce desktop:

$ su -c 'yum -y group install xfce-desktop'

LXDE

The following command installs the LXDE desktop:

$ su -c 'yum -y group install lxde-desktop'

MATE

The following command installs the MATE desktop:

$ su -c 'yum -y group install mate-desktop'

Security

The following command installs FSL (the Fedora Security Lab):

$ su -c 'yum -y group install "Security Lab"'

KDE

The following command installs the KDE desktop:

$ su -c 'yum -y group install kde-desktop'

Working from the Command Line

Before the introduction of the GUI, UNIX and then Linux provided only a textual (command-line) interface (CLI). Today, a textual interface is available when you log in from a terminal, a terminal emulator, or a textual virtual console, or when you use ssh to log in on a system.

Advantages of the textual interface

Although the concept might seem antiquated, the textual interface has a place in modern computing. In some cases an administrator might use a command-line tool either because a graphical equivalent does not exist or because the graphical tool is not as powerful, flexible, or refined as the textual one. For example, chmod (page 193) provides finer granularity than its GUI counterpart (File Browser Object Properties window, Permissions tab; page 105). On a server system, a graphical interface might not even be installed. The first reason for this omission is that a GUI consumes a lot of system resources; on a server, those resources are better dedicated to the main task of the server. Additionally, security considerations mandate that a server system run as few tasks as possible because each additional task provides an additional attack vector.

You can also write scripts using the textual interface. Using scripts, you can easily reproduce tasks on multiple systems, enabling you to scale the tasks to larger environments. When you are the administrator of only a single system, using a GUI is often the easiest way to configure the system. When you act as administrator for many systems, all of which need the same configuration installed or updated, a script can make the task go more quickly. Writing a script using command-line tools is frequently easy, whereas the same task can be difficult to impossible using graphical tools.

Pseudographical interface

Before the introduction of GUIs, resourceful programmers created textual interfaces that included graphical elements such as boxes, borders outlining rudimentary windows, highlights, and, more recently, color. These textual interfaces, called pseudographical interfaces, bridge the gap between textual and graphical interfaces. The Midnight Commander file management utility (mc; midnight-commander.org) is a good example of a utility with a well-designed pseudographical interface.

Command-line (bash) coverage

This section introduces the Linux CLI. Chapter 5 is the first of three chapters dedicated to the Bourne Again Shell (bash). Chapter 7 describes some of the more important utilities you can use from the command line. Chapter 9 covers advanced bash concepts. Chapter 27 describes shell programming using bash. Most of the examples in Parts III and IV of this book use the CLI, adding examples of graphical tools where available.

Running Commands from the Command Line

This section describes three ways to work from the command line: using a terminal emulator, using a virtual console, and logging in remotely. If the local system does not support a graphical interface, you have no choice: You must work from the command line—skip to “Logging Out” on page 121.

Using a Terminal Emulator/Shell

A terminal emulator is a window that presents a CLI (command-line interface); it functions as a textual (character-based) terminal and is displayed in a graphical environment. To open the GNOME terminal emulator named Terminal (gnome-terminal; Figure 4-23), give the commandgnome-terminal from an Enter a Command window (ALT-F2) or a terminal emulator. Because you are already logged in and are creating a subshell in a desktop environment, you do not need to log in again.

Figure 4-23 A Terminal (emulator) window

Terminal displays your username, the name of the system you are working on, and the name of the directory you are working in (the working directory) on the titlebar. Figure 4-23 shows sam working on the system named guava. He is working in his home directory (page 143), which the shell refers to using a tilde (~; page 182).

You can run character-based (textual) programs that would normally run on a terminal or from the console in a terminal emulator window. You can also start graphical programs, such as gnome-calculator, from this window. A graphical program opens its own window.

To open an additional terminal session within the same Terminal window, right-click the window and select Open Tab from the context menu. A row of tabs appears below the menubar as gnome-terminal opens another terminal session on top of the existing one. Add as many terminal sessions as you like; click the tabs to switch between sessions.