Red Hat Linux 9 Professional Secrets [Electronic resources] نسخه متنی

Linux Desktop

Let’s face it—typing cryptic UNIX commands on a terminal is boring. Those of us who know the commands by heart may not realize it, but the installed base of UNIX is not going to increase significantly if we don’t make the system easy to use. This is where the X Window System, or X, comes to the rescue.

X provides a standard mechanism for displaying device-independent bitmapped graphics. In other words, an X application can display its graphic output on many different machines that use different methods to display text, graphics, and images on the monitor. X is also a windowing system, meaning it enables applications to organize their output in separate windows. X uses a client/server architecture and works over the network, so you can run X applications on various systems on the network while the output appears in windows that are managed by an X server running on your system.

Although X provides the mechanism for windowed output, it does not offer any specific look or feel for applications. The look and feel comes from GUIs, such as GNOME and KDE, which are based on the X Window System.

As for the GUI, Linux includes two powerful graphical desktop environments: KDE (K Desktop Environment) and GNOME (GNU Network Object Model Environment). When you install Red Hat Linux, you can choose which desktop you want or can install both and switch between the two. GNOME and KDE provide desktops similar to the ones in Microsoft Windows and the Apple Mac OS. GNOME also comes with the Nautilus graphical shell that makes it easy to find files, run applications, and configure your Linux system. With GNOME or KDE, you can begin using your Linux workstation without having to learn UNIX commands. However, if you should ever need to use UNIX commands, all you have to do is open a terminal window and type the commands at the shell prompt.

Red Hat Linux also comes with many graphical applications that run under X. The most noteworthy programs relate to image display and editing. The first is GIMP—the GNU Image Manipulation Program—a program with capabilities on a par with Adobe Photoshop; the second program is ImageMagick.

Another important aspect of the X Window System is that you can run applications across the network because X uses a client/server architecture. The X server runs at the workstation and controls the display, keyboard, and mouse. Client applications send requests to the X server to receive user input and display output. For example, you might run an X application on a server somewhere on the network but view that application’s output and interact with it from your Linux desktop that’s running a X-based GUI. In other words, with X, your Linux PC becomes a gateway to all the other systems on the network.

Motif is the dominant GUI in the UNIX marketplace, but it’s not packaged with Linux because the Open Software Foundation does not distribute Motif for free. Motif has a look and feel similar to Microsoft Windows and includes the Motif Window Manager (MWM) and the Motif toolkit for programmers. You can download OpenMotif for Linux from

http://www.motifzone.net/ . In addition to Open Motif from The Open Group, another option for Motif for Linux is LessTif, a free version of Motif distributed under the GNU General Public License (visit the LessTif home page at

http://www.lesstif.org for the latest information on LessTif). Red Hat Linux comes with LessTif and is automatically installed if you select the X Software Development package group during Red Hat Linux installation.

If you need Motif for a project, using a Linux PC with a copy of OpenMotif or LessTif installed is an economical way to set up a software-development platform. If you have a consulting business, or if you want to develop X and Motif software at home, Linux is definitely the way to go.

Along with GNOME and KDE, you get two more options for developing GUI applications in Linux. GNOME comes with a toolkit called Gtk+ (GIMP toolkit), and KDE comes with the Qt toolkit. If you do not want to learn Motif, you may want to use Gtk+ or Qt for your GUI applications.

Office productivity software—such as word-processing, spreadsheet, and database applications—is an area in which Linux used to be lacking. This situation has changed, though. Red Hat Linux comes with the OpenOffice.org office-productivity applications. In addition, there are several prominent commercially available office-productivity applications for Linux that are not included on the companion CD-ROMs. Applixware Office—now called Anyware Desktop for Linux—is a good example of productivity software for Linux (

http://www.vistasource.com/products/ ). Another well-known productivity-software package is StarOffice from Sun Microsystems (

http://www.sun.com/staroffice/ ). CrossOver Office, from CodeWeavers, is a commercially available software package that enables you to install your Microsoft Office applications (only Office 97 or Office 2000, not Office XP) in Linux. Furthermore, many existing software packages (designed for UNIX workstations with the X Window System) can be readily ported to Linux, thanks to Linux’s support for portable standards such as POSIX and the X Window System.