Red Hat System Administration I
Use the GNOME graphical environment to launch applications, especially the graphical terminal program.
Objectives
After completing this section, students should be able to log into the Linux system using the GNOME 3 desktop environment to run commands from a shell prompt in a terminal program.
The GNOME desktop environment
The desktop environment is the graphical user interface on a Linux system. The default desktop environment in Red Hat Enterprise Linux 7 is provided by GNOME 3. It provides an integrated desktop for users and a unified development platform on top of a graphical framework provided by the X Window System.
The GNOME Shell provides the core user interface functions for the GNOME desktop environment. The gnome-shell application is highly customizable. By default, RHEL 7 users use the "GNOME Classic" theme for gnome-shell, which is similar to the GNOME 2 desktop environment. Another available option is the "modern" GNOME 3 theme used by the upstream GNOME project. Either theme can be selected persistently at login by selecting the gear icon next to the button when entering the user's password.
The first time a new user logs in, an initial setup program runs to help them configure basic account settings. The GNOME Help application is then started on the Getting Started with GNOME screen. This screen includes videos and documentation to help orient new users to the GNOME 3 environment. GNOME Help can be quickly started by pressing F1 in gnome-shell, by selecting → → , or by running the yelp command.
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Parts of the GNOME Shell
The various parts of the GNOME Shell have specific names and purposes. These parts include the following:
top bar: The bar that runs along the top of the screen. The top bar provides the and menus, and controls for volume, networking, calendar access, and selecting between keyboard input methods (if there are more than one configured). Under the menu for the user's name are options to adjust account settings, lock the screen, switch users, log out of the system, or shut it down.
Applications menu: This menu on the top bar provides a way to start applications, categorized into submenus. The Activities Overview can also be started from this menu.
Places menu: This menu to the right of the menu provides quick access through a graphical file manager to important menus in the user's home directory, to
/, and to exports and file shares on the network.window list: The bar that runs along the bottom of the screen. The window list provides an easy way to access, minimize, and restore all windows in the current workspace. On the right corner is an indicator to tell the user which workspace they are on and how many are available.
message tray: The message tray provides a way to review notifications sent by applications or system components to GNOME. If a notification occurs, normally the notification first appears briefly as a single line at the bottom of the screen, and a persistent indicator appears in the lower right corner to inform the user of how many notifications have been recently received. The message tray can be opened to review these notifications by clicking the indicator or pressing Super+m. The Super key (sometimes called the Windows key), is found near the lower left corner of an IBM PC 104/105-key keyboard. The message tray can be closed by pressing either Esc or Super+m again.
Activities Overview: This is a special mode that helps a user organize windows and start applications. The Activities Overview can be started by selecting → . The three main areas of the Activities Overview are the dash on the left side of the screen, the windows overview in the center of the screen, and the workspace selector on the right side of the screen. The Activities Overview can be exited by pressing the Esc key.
dash: This is a configurable list of icons of the user's favorite applications, applications which are currently running, and a button which can be used to select arbitrary applications. Applications can be started by clicking on one of the icons or by using the grid button to find a less commonly used application. The dash is also sometimes called the dock.
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Workspaces
Workspaces are separate desktop screens which have different application windows. These can be used to organize the working environment by grouping open application windows by task. For example, windows being used to perform a particular system maintenance activity (such as setting up a new remote server) can be grouped in one workspace, while email and other communication applications can be grouped in another workspace.
There are three methods for switching between workspaces. One method is to click the indicator in the right corner of the window list and select the desired workspace. Another, perhaps the fastest, is to press Ctrl+Alt+UpArrow or Ctrl+Alt+DownArrow to switch between workspaces sequentially. A third is to switch to the Activities Overview and click the desired workspace.
An advantage of using the Activities Overview is that windows can be clicked and dragged between the current workspace and one of the others by using the workspace selector on the right side of the screen and the windows overview in the center of the screen.
Note
Using the Ctrl+Alt+UpArrow or Ctrl+Alt+DownArrow key combinations to change workspaces does not work in the virtual learning environment. Instead, the workspace applet on the panel or the Activities Overview must be used to change workspaces.
Starting a terminal
To get a shell prompt in GNOME, start a graphical terminal application such as GNOME Terminal. There are several ways to do this. Here are the three most commonly used methods:
Select → → .
On an empty desktop, right-click, or press the Menu key, and select from the context menu that appears.
From the Activities Overview, select Terminal from the dash (either from the favorites area or by finding it with either the grid button (inside Utilities grouping) or the search field at the top of the windows overview).
When a terminal window is opened, a shell prompt displays for the user that started the graphical terminal program. The shell prompt and the terminal window's title bar will indicate the current user name, host name, and working directory.
Locking the screen or logging out
Locking the screen, or logging out entirely, can be done from the menu for the user's name on the far right side of the top bar.
To lock the screen, select → or press Ctrl+Alt+L. The screen will lock if the graphical session is idle for a few minutes.
A lock screen curtain will appear that shows the system time and the name of the logged-in user. To unlock the screen, press Enter or Space to raise the lock screen curtain, then enter the user's password on the lock screen.
To log out and end the current graphical login session, select → from the top bar. A dialog window will appear, giving the option to the log out within 60 seconds, or confirm the action.
Powering off or rebooting the system
To shut down the system, select → from the top bar or press Ctrl+Alt+Del. In the dialog that appears, the user can choose to , the machine, or the operation. If the user does not make a choice in this dialog, the system will automatically shut down after 60 seconds.
References
GNOME Help
yelp
GNOME Help: Getting Started with GNOME
yelp help:gnome-help/getting-started
