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How to Customize Your Linux Desktop - From GTK to Compiz

Will Kraft — Fri, 26 Jun 2009 10:30:00 -0500

The days of ugly Linux desktops are a thing of the past. Modern distros include many tools and options that enable them to look good and be more useful.

Unlike Windows, Linux has several different widget toolkits. The most well-known widget engines are GTK+, (distributed with GNOME) and QT. (pronounced “cute”) Widgets are the various elements which make up a program's GUI: scrollbars, arrows, checkboxes, etc. However, take note that QT or GTK widgets are not the same thing as desktop widgets.

Widgets and other things like window chrome (the toolbars, panels, etc. of a programs interface) and window decoration (the window's title bar, minimize/maximize/close buttons, and the window border) are the various elements that, when joined together, create a theme for QT or GTK. It is possible to modify the various themes in Linux to change how they look or even create your own. This article will address the various resources that are out there to help make your desktop look its best and help you get the most out of it.

Manipulating GTK Themes

GTK themes are among the most versatile when it comes to customization. Originally created for the GIMP, (GNU Image Manipulation Program) GTK is used in many applications, especially in the GNOME desktop environment. Some of the more elaborate GTK themes use rasterized PNG graphics to create the visual appearance of the widgets, but most GTK themes use effects created by the GTK engine itself. Each installed GTK theme is stored in its own folder in /usr/share/themes and has a gtkrc file that is used to store the parameters of the theme, such as element colors, size, position, etc. Although gtkrc files are plain text and are therefore human-readable, there is still a small learning curve in relation to working with them.

Fortunately, GNOME's Appearance module has a built-in tool to allow you to create your own themes in an easy-to-use interface. (To access the Appearance module in GNOME, go to System → Preferences → Appearance → Customize) This tool uses themes that have already been installed and allows you to mix and match parts from different themes to create your own hybrid designs; you can use icons from one theme, widgets from another, window decorations from yet another, etc. The more themes you have installed, the more versatile this tool can be, since the possible number of combinations can rise exponentially if you install only a few extra themes. For this reason, it is a good idea to install as many themes as possible, since each theme (even ones you don't like) can provide a larger inventory of spare parts to work with.

This tool is best for those who don't know how to work with gtkrc files directly or don't want to spend too much time creating their own theme. If you're more artistically inclined, you may wish to create your own themes from scratch. Since themes can be image-based, you are limited only by your creativity. A good way for beginners to learn how to create themes is to download a few and then analyze them to see how other artists made theirs. By using pre-existing themes as a guide, you can then create one of your own.

Plasma Themes

Unlike GTK themes, Plasma themes used in KDE4 are predominately made up of scalable vector graphics. (SVG) These are made in vector graphics editing software like Inkscape, Karbon, or anything else that can export SVG. (even Adobe Illustrator)

KDE4's appearance management system is much less straightforward than GNOME. While GNOME has one interface module to control its appearance, KDE4 has several. The modules which allow you to switch between themes is located on the desktop right-click menu instead of the control center, so newbies may be confused at first about how to switch between different themes.

Most Plasma themes are quite simple, (mostly glass-like with a few minimalistic and metallic variants) and only affect desktop widgets, the taskbar, etc. Windows are not affected by the Plasma theme you use, since they are not part of the Plasma system. Rather, window appearance is governed through choosing a color scheme and a widget/window decoration style just like in classic KDE. This is done through the Appearance module in the KDE4 control center and is rather straightforward. KDE has a built-in tool to acquire new wallpapers, Plasma themes, etc. so adding additional Plasma themes is simple.

Next, how to troubleshoot some common theme-related problems.

Dealing with Common Theme-related Problems

Since most programs are set up to use light-colored themes, you may encounter problems if you use a dark-colored or otherwise unusual theme. OpenOffice.org in particular has an annoying bug where the toolbar icons will switch to a rather awful-looking high-contrast icon pack without asking you when a dark theme is detected by the program. If the high-color icon pack is not installed, (as it seldom is out of the box) Openoffice.org will display text instead of icons, which looks even worse and is very space-inefficient. Fortunately, this problem can be easily dealt with.

The easiest way to rectify this problem is to change the icon pack in the OpenOffice.org configuration. (this is done through Tools → Options → View in OpenOffice.org) If the first method fails to work, there is a way to trick OpenOffice.org into using the icon set you want to use. OpenOffice.org stores its icon graphics in zip files, which makes them very easy to manage. These icon packs are buried rather deeply in the filesystem, so they can be difficult to find. Ubuntu stores them in /usr/lib/openoffice/share/config/, but the location varies from distro to distro.

To fix the dark theme bug, all you must do is rename the icon pack of your choice (like images_human.zip) to “images_hicontrast.zip”. You should replace “images_hicontrast.zip” if it exists. After applying this fix and re-starting OpenOffice.org, OpenOffice.org will think it is using high-contrast icons, but it will actually be using the icon set you want to use and icons will look the way you want them to.

Sometimes, websites use stylesheets that conflict with your system colors, particularly if you use a dark theme with white text. Many stylesheets set a certain background color on form elements and neglect to set a particular text color. Quite often, this results in white or light-colored text on a light background, since system colors are used for any attributes not defined by stylesheets. Although you can configure Firefox to use system colors for web elements, this solution is often too imprecise and makes most websites look ugly. Fortunately, there is a better way.

One of Firefox's greatest strengths is its sheer hackability. Firefox has general settings in its about:config section that allow you to fine-tune the browser's performance and configuration, but Firefox can also be customized very precisely on a per-user basis. Each Firefox profile has its own userContent.css file. (not to be confused with userChrome.css, which is used to manipulate the Firefox GUI itself) userContent.css does not exist by default and must be created in ~/.mozilla/firefox/[your_profile_name]/chrome. Fortunately, Firefox provides a template to start with for both userContent.css and userChrome.css. userContent.css is used to declare rendering guidelines on either a global basis or for specific websites.

If you are using an unusual color scheme, you are able to use userContent.css to force Firefox to override a site's stylesheet in favor of your own preferences. As the extension suggests, userContent.css is just like any other cascading style sheet, but it does have a few Firefox-specific differences. If you have any CSS experience at all, you should not find it too difficult to configure userContent.css. (If you are new to CSS, it is easy to learn and rather straightforward) If you run into problems, there are many online guides that cover the differences between userContent.css and standard CSS in detail in addition to the many CSS tutorials out there.

Desktop Compositing

Many operating systems have shifted from using software rendering for desktop effects, instead opting for 3d-accelerated desktop effects. Linux has offered compositing features for years, starting with the original Compiz Quinn, followed by Beryl. Those two projects have culminated in Compiz Fusion, which is discussed in-depth in this section.

Compiz Fusion Overview

GNOME and KDE 3 have built-in interfaces to use Compiz Fusion, a desktop compositing tool and window manager that is a drop-in replacement for the Metacity Window manager in GNOME and the old Kwin window manager in KDE 3.5. KDE4 has its own compositing engine, but Compiz Fusion is able to override it. Compiz Fusion is a descendant of and replacement for Beryl, a compositing manager that was popular several years ago. Beryl was originally a fork of the original Compiz Quinn project; both projects are now obsolete.

Compiz Fusion uses your computer's 3d-acceleration capabilities to produce special visual effects that conventional software-driven graphics are not able to match. The extra burden of rendering these effects is shifted to the GPU on your graphics card or chipset (which would otherwise be idle) instead of the main CPU that is used for everything else. Because of this, you need to make sure your graphics card or chipset is supported in Linux and there is a driver for it if necessary if you want Compiz Fusion to work. (Nvidia support is very good from our experience) Compiz Fusion runs with very little overhead and does not slow down old or low-end machines.

Compiz Fusion can do much more than Windows Vista's “Aero” compositing engine. Although GNOME and KDE 3.5 include several presets on some distros, (notably Ubuntu) Compiz can be fine-tuned with the Compiz Config Settings Manager. (CCSM) CCSM can be invoked either through your favorite desktop environment/window manager's menu system or by typing “ccsm” into a terminal. (assuming that CCSM is installed)

Working with Compiz Fusion

CCSM gives you the full scope of effects that the Compiz Fusion engine is capable of. It can replicate all of the features that are in Vista's Aero, and Compiz still has plenty of unique features of its own that have been inherited from Beryl and the original Compiz. Many people have the misconception that Compiz Fusion is merely eye-candy that is meant to “wow” and impress new users. Although there is a grain of truth to that, it is not fair to over-generalize. While some of Compiz's functionality is purely decorative, (and can be way over the top if you use all of it at once) some of it is meant to compensate for certain disabilities or to help make using your computer easier.

For instance, the ADD helper tool can help those afflicted with the disorder by dimming all windows except the current active one to minimize distraction and to make the task at hand easier to focus on. Likewise, the magnifier tool makes text easier to read on programs that do not support dynamic text zooming and the negative tool can make some interfaces easier to read by inverting the colors. All of these effects could not be easily implemented through conventional software acceleration without slowing the computer down significantly.

On distros like Ubuntu, Compiz Fusion is installed by default but must be activated manually once the requisite video card drivers have been acquired. To enable Compiz Fusion in GNOME, go to System → Preferences → Appearance → Visual Effects and select the preset level you want or use CCSM to configure the desired effects. (CCSM is not required to use the presets in GNOME's Appearance module)

Emerald Overview

Although Compiz Fusion renders the actual windows and controls their behavior effects, you are still stuck with the original GNOME/KDE window decorations by default. However, there is a window decorator program called Emerald that allows you to use better-looking window decorations. Emerald was originally designed to work with Beryl, hence the naming trend; the gemstone emerald is technically a variety of Beryllium. Emerald has been around for awhile, but it still works as a drop-in replacement for the standard Window decorator in GNOME or KDE.

Emerald uses “theme” files to produce window decoration effects. These themes each use an engine that specializes in a different effect (e.g. TruGlass for transparency effects and Vrunner for gradients) Each theme is built around a specific engine; this is a factor to consider when constructing your theme since switching engines can produce vastly different effects.

If you want to use Emerald, you must install it manually. Fortunately, Ubuntu and many other distros have Emerald in their repositories; Ubuntu users need only type “sudo apt-get install emerald” to install Emerald. By default, Compiz Fusion will not use Emerald; you must manually invoke it through CCSM in the “window decorations” module. To do this, locate the “command” field in the window decoration module and replace the original value with “/usr/bin/emerald --replace”. The changes should take effect at the next login. You can invoke the changes immediately by opening a terminal and running “nohup emerald --replace” after re-configuring CCSM to use Emerald with the previous command.

To avoid problems, make sure you have at least one Emerald theme installed before you enable Emerald in Compiz Fusion. If you try to use Emerald without any themes, no window decorations will be rendered at all.

Creating Emerald Themes

If you just want to use other people's Emerald themes, there is an abundance of them at gnome-look.org. To install a theme, extract the .emerald theme file you wish to install from its tarball to a location in your home folder and click the “import” button in the Emerald program interface. Locate the file you extracted, select it, and then click “open” to install it. Emerald provides a list of installed themes; to switch to a theme, click on its entry in the main list.

The Emerald program also has a built-in interface for creating themes. Although the feature is called “Edit Theme” it can do far more than that. Once you understand how Emerald handles various graphics, it is possible to create new ones from scratch while using pre-existing ones as a reference. You do not need to include effects like drop shadows or glow in the image components of your theme, since Emerald is capable of generating such things dynamically.

Desktop Widgets

In recent years, Widgets have become standard fare in all modern operating systems, although they take different forms depending on the operating system in question. (OS X has the Dashboard while Vista has the Sidebar) Linux also features multiple widget engines for multiple desktop environments to fill space on the desktop that would otherwise be wasted. This section will discuss the various theme engines that are available for Linux and what each of them can do.

Screenlets

GNOME's only real widget system (aside from various things that can be placed on the GNOME panels) is an external program called Screenlets. As far as widgets go, the Screenlets program is very decent. It has a wide variety of widgets available out of the box, with multiple calendars, clocks, system monitors, email checkers, RSS readers, etc. to choose from. From our experience, the Screenlets program is the best widget system available for Linux since the Widgets work equally well on GNOME, KDE and many other window managers.

In Ubuntu, the Screenlets Manager can be installed by running “sudo apt-get install screenlets”. The Screenlet manager software also allows you to install additional screenlets; (most are located on Linux resource sites like gnome-look.org) these must be extracted to your home folder and be placed in the “.screenlets” directory.

Plasma Widgets

The widget system in KDE4 is rather unique. KDE4 was originally meant as a reinvention of the traditional desktop concept; virtually everything (including any desktop shortcut icons) is made out of individual entities called plasmoids that are directly integrated with the new Plasma rendering system. This is a radical departure from other widget systems mentioned in this article, since those are essentially programs that run on top of another desktop environment without actually being part of it.

Plasma widgets are simple to use. To add widget plasmoids to your desktop, right-click anywhere on the desktop in KDE4 and choose the “Add Widgets” option. Many distros include only a few widgets out of the box, but more are available. (KDE4 includes a built-in tool for acquiring new widgets, wallpapers, etc.) However, the selection is not as diverse as Screenlets or SuperKaramba, but this is only because KDE4 is still fairly new. Given time, this deficiency should resolve itself.

If KDE4 is present, nothing else needs to be installed to be able to use KDE4 widgets. KDE4 widgets are not available in any other desktop environment.

SuperKaramba

SuperKaramba saw most of its use several years ago, and still serves as the widget engine for older versions of KDE. SuperKaramba is a remake of Karamba, an even older widget engine. SuperKaramba took Karamba's foundation and added additional features to make widgets easier to use (the original Karamba had no GUI and no easy way to add new widgets)

Due to its age, SuperKaramba has plenty of widgets for every conceivable purpose, and many of them can be found at KDE-oriented resource sites like KDE-look.org. SuperKaramba is best used in older versions of KDE, since KDE4 has its own built-in widget engine and GNOME is not able to handle transparency in SuperKaramba widgets very well. Furthermore, the Screenlets program has the capability to use SuperKaramba widgets, although that feature is still in beta.

The Complete Beginner's Guide to Linux

Will Kraft — Tue, 07 Apr 2009 22:00:00 -0500

We are certain that many of you want to try Linux to see what it is like, but have no idea where to start or how to get into it. This is our complete guide to introduce you to the Linux environment and teach you how to adjust to it if you are a new user. From picking the perfect distro for your needs to partitioning and installing the OS, this guide will show you the step-by-step process of getting Linux up and running on your machine. We break down the fundamental differences between the Linux and Windows graphical interfaces, and show you how to utilize Linux's terminal like a pro. Whether this is your first time running Linux or you've been an open-source accolyte for years, you'll find lots of useful tips and reference information in this comprehensive overview.

Part 1: Finding the Right Distribution

Part 2: Partition and Installation

Part 3: The Linux GUI

Part 4: Introduction to the Terminal

Part 1: Finding the Right Distribution

One of the hardest things to do while starting out is finding a distro that is right for you. Many users try several before settling on one of two that they really like. Once they find a distro that feels right, they are often reluctant to switch unless the distro becomes unsuitable for their needs for whatever reason.

Arguably, the most important factor in choosing a distro is your general level of experience with Linux. Not all distros cater to the same intended user audience. Some (like Ubuntu) are designed to be more accessible to novice users while other distros have a greater learning curve. Distros like Gentoo or Slackware are not necessarily meant to be “harder” than Ubuntu; they simply work out that way because they are less automated and often sacrifice ease of use for the greatest possible user control or system transparency. Many advanced users know what they are doing and prefer doing things their way.

Part 2: Partition and Installation

This chapter is going to walk you through downloading and burning a CD image of your chosen distro(s), the traditional way of partitioning and setting up a dual-boot system, and another way to dual-boot without repartitioning. Instead of providing a step-by-step tutorial for a specific installation process, our goal is to educate you on the underlying concepts in a more generalized way that you will be able to apply towards many different Linux distros.

We cover software acquisitioning, hard drive partitioning, distro testing, and the actual install. You should also read our previous guide to installing Ubuntu for further instructions.

Part 3: Choosing Your Window Manager and Desktop Environment

The Linux graphical user interface (GUI) system may be very different from what you are used to if you are coming from a Windows or Mac OS X background. The GUI of an operating system is commonly referred to as its shell. While virtually all versions of Windows since Windows 95 have used variations of the same basic shell (explorer.exe), there are numerous shells available for the Linux GUI. These Linux shells are called window managers and desktop environments. The term window manager is used to address the simple core user interface of a shell, while the term desktop environment is much more inclusive, covering the shell itself in addition to the various other programs that are integrated with it.

Due to the vast number of window managers available for Linux, many new users often feel overwhelmed at the idea of having to learn their way around them. We must emphasize that many people experiment with several window managers before settling down with one that feels right for them, and there certainly is no need to learn all of them. Due to their modular nature, it is common to have several window managers installed at once.

Much like part one of this series that dealt with choosing a distro, this guide will help you to choose a window manager/desktop environment by introducing you to several of them and addressing their strengths and weaknesses.

Part 4: Introduction to the Terminal

Traditionally, most new users have always been reluctant to experiment with the command line interface, (commonly referred to as the terminal) yet it has always been one of the most important parts of learning Linux. Once you understand the terminal, Linux will finally open up to you. The terminal is easily the most powerful part of a Linux system; it is your way of being able to work directly with the operating system without any barriers or hindrance.

This section will cover basic terminal usage in addition to ways to enhance basic commands. For the sake of simplicity, we will only address the underlying concepts of shell scripting instead of covering it in detail. We saved this part of our guide for last because it is typically the most difficult to grasp. However, the terminal is fairly easy to understand when broken down into simple concepts.

Bonus: How to Compile Programs From Source in Linux

Although the introduction of package management on most distros, less diversity in CPU architecture among the user base, and massive increases in hardware speed have largely reduced or eliminated the need to compile software yourself, there are still a few instances where you would have to do so. Although the various official and unofficial software repositories for Ubuntu and other distros include most of the tools that the average user would need for any given purpose, the repositories are not completely comprehensive. Old packages sometimes get dropped and updated versions are often slow to be added. It may also take a release cycle or more for brand-new programs to be included.

While Ubuntu and Debian have “backports” repositories that have fairly new packages in them, many other distros do not have such a resource. For large projects with large community support, the developer may offer nightly builds, but this is not the case for most projects. The only reliable way to get bleeding-edge software (stability issues aside) is to either find a repository that has it or download the source code from the developer and build it yourself. We show you how!

Read on to find your inner penguin! >>

The Beginner's Guide to Linux Part 4: Introduction to the Terminal

Will Kraft — Tue, 07 Apr 2009 20:00:00 -0500

Part 1: Finding the Right Distro

Part 2: Partition and Installation

Part 3: The Linux GUI

Part 4: Introduction to the Terminal

This guide will cover basic terminal usage in addition to ways to enhance basic commands. For the sake of simplicity, we will only address the underlying concepts of shell scripting instead of covering it in detail. We saved this part of our guide for last because it is typically the most difficult to grasp. However, the terminal is fairly easy to understand when broken down into simple concepts.

Overview of the Linux Terminal

Linux has many different shells that you can use for your terminal. One of the most common shells is called Bash, an abbreviation for “Bourne-Again Shell”. (a successor to the original Bourne Shell) Other popular shells include the original Bourne Shell, (sh) the Korn Shell, (ksh) and the C shell. (csh) If you are running a window manager, you would interact with a shell program through a terminal emulator like Xterm, GNOME Terminal, Konsole, or something similar. However, if you are not running a window manager or any other GUI, the terminal is your only way of interacting with the system. Generally, the terminal is a fail-safe repair system if Xorg (the GUI system) were to malfunction.

The Bash Shell

This article will focus primarily on Bash, but is applicable to other shells as well. Each shell program has its own strengths and weaknesses and is different from the others, but you are not likely to experience this very much unless you get into complicated shell scripting and programming. In the case of simple commands, the various shells operate in much the same way.

Gnome and Xterm

Basic Terminal Concepts

Although Bash and other terminals vaguely resemble DOS, there are fundamental differences. While DOS is a full (albeit simple) operating system with the core functionality built in, Bash is simply a command shell that provides an interface to the operating system it runs on. The first thing you must understand is that Bash has very little built-in functionality of its own. Every time you run a command in Bash, (no matter what it is) you are actually invoking another program as a separate process. Bash and other similar shells use a set of core utilities for basic file operations. (Some of the most important of these may be found at the end of this article) Text-based utilities like file copying/deletion/renaming, process management, and disk usage are all handled externally; although they appear to be part of Bash, that is not the case.

Since the shell assumes that all programs are either in /bin or /usr/bin, Bash does not need a full pathname or require you to navigate to a specific directory to start a program. To run a program, simply type the program name at the command prompt. (e.g “vim” or “firefox”) In this article, we will refer to simple commands like these as “base commands.”

The tilde (~) symbol is used as a reference to your home directory. In all instances there you would normally have to provide the full pathname of your home directory, the ~ symbol may be used instead as a matter of convenience. For instance, ~/sub_folder is the same as /home/<your home folder>/sub_folder. To navigate to your home folder from anywhere in the filesystem, you need only type “cd ~”.

Like the rest of Linux, a shell has two levels of privilege: regular users and super users. At the command prompt, Bash will list the name of the current user in addition to the name of the machine the terminal is running on. The user listed first and the machine listed second, with an @ symbol separating them. (e.g. frodo@shire or root@aux) Bash will also list the current directory as well. Many other shells are far less verbose and list only “$” for all regular users and “#” for the root account.

Each shell can run only one command at a time. However, you can run as many shell processes as you wish at the same time under a GUI with a terminal emulator. Many terminal emulators have a tab system that lets you easily switch back and forth between any shells that you have open. Without a GUI, you can run up to seven terminals at a time on most distros; these terminal processes are assigned a prefix of “tty” (Teletype) and a number. tty1-tty6 are generally available at any given time, whereas tty7 is normally used to run the GUI system and is therefore not available for other use. To switch to a different tty, press CTRL+ALT+Fx, where x is the number of the tty you would like to use. For example, to switch to tty3, press CTRL+ALT+F3.

Each program started from a terminal becomes bound to that terminal as a child process; if you close a terminal, any child processes managed by that terminal are closed as well. If you want to keep a process running no matter what happens to its parent terminal, you must precede the command with “nohup” (short for “no hangup”) when you launch it. Instead of displaying output in the terminal window as is the norm, programs launched with nohup have all output written to a file called nohup.out.

To terminate a running program before it is supposed to finish, press CTRL+C.

Switches

Many programs can perform multiple functions, so additional parameters called switches are used in addition to the base command to provide access to this functionality. Switches are preceded by a dash, placed after the base command, and use letters or numbers as references to certain functions. Since you can invoke multiple switches at once, (e.g. tar -czvf ) it is possible to fine-tune the actions of a program in very specific ways that the base command all by itself would not allow. Switches can be grouped together as shown in the previous example.

You should remember that switches are case-sensitive and can do different things depending on whether they are uppercase or lowercase; for example, “-R” is not the same thing as “-r”. If you use switches that happen to conflict with each other or are invalid, the program will display an error message that explains the problem. To see all possible switches for a program, you should refer to its manual page. (run “man <program name>”) The manual page will also provide detailed usage parameters for a program in addition to examples and background information. Almost every program has a manual page associated with it, often in addition to more conventional documentation.

Wildcards

Bash and other shells support the use of wildcards, which are used to substitute unknown or non-designated characters in commands. The wildcard symbol is the asterisk. (*) Wildcards differ from variables, which are used to bind specific values in shell scripts and more advanced Bash applications.

Wildcards are frequently used with the list command. (ls). Using wildcards, you can force ls to show only certain types of files in its output instead of everything. For example, “ls *.png *.html” will display all PNG and HTML files in a directory.

Wildcards may also be used to show all files in a directory that start with a certain letter; “ls a*” will display any file that begins with the letter a. It is also possible to apply a wildcard to a set of characters. For example, “ls [abc]*” will display any file in a directory that begins with a, b, or c.

<< Back to Part 3

Program targets

Many programs provide you with the option of immediately acting against a specific target entity when the program starts. This target entity may be practically anything, (a file, directory, network address, or system device) depending on the nature of the program. A target may be located anywhere in the filesystem, and it may be invoked from any directory (provided the pathname is correct) For example, if you are in your home director and wish to edit a file in a subfolder, there is no need to change to the subfolder before opening the file.

Generally, the target should be specified after the base command and any switches. (e.g. “vim -R myfile.txt”) Sometimes, switches may have targets of their own in addition to the main program target. In such instances, the manual page will tell you what types of switch/target combinations the program will accept.

Although most filenames are either single words or separated by underscore characters (e.g. file_1) The terminal supports multiple worded filenames as target entities. However, spaces in filenames must be preceded by a backslash, otherwise the shell will treat each word independently. (often causing an error) For instance, Bash would correctly process “multiple\ worded\ filename.txt” as “multiple worded filename.txt”. Omitting the backslashes would cause the shell to incorrectly interpret the filename as “multiple”, “worded”, and “filename.txt”.

Working with Input and Output

Joining commands together

If you have two or more commands that you wish to run in sequence, type them on the same line and place “&&” between each separate command. The commands will then be executed in order, from left to right.

Pipelines

Software pipelines allow you to feed the output from one program directly into another. Like the && operator, pipelines allow you to execute multiple commands in a specific sequence. However, a pipeline automatically takes the output from the previous command and feeds it into the next command whereas the && operator treats each command independently. Pipelines are useful primarily because they allow further processing of a command and allows multiple interdependent commands to be chained together when necessary. The pipeline is invoked by placing the “|” symbol between two separate commands on the same line.

For example, the grep utility is designed to search for a specific keyword you provide. If you were to run a program like ls, you can use grep to isolate a certain file (e.g. file1.jpg) from what could be a very long file list, even with wildcard filtering. If you were to run “ls | grep file1.jpg”, only file1.jpg would be listed in the terminal (if it exists) even though ls might return much more output under normal conditions.

Output Redirection

Sometimes, you may want to save terminal output. While you could use a pipeline to dump it into a text editor, there is an easier way. Using the greater-than (>) symbol, you can save terminal output to a text file. For example, running “cat file1 file2 > file3” will join the contents of file1 and file2 together and will then save the resulting output as file3.

Be careful with this, since any existing file with the same name as the one you specify will automatically be replaced. To append the output to an existing file, use “>>” instead of “>”.

Shell Scripting Concepts

While the simple operators described in the previous section can allow you to create complex commands, true shell scripting can do much more by taking the principles described in the previous section to a whole new level. A Linux shell script works just like a Windows batch file in a sense; both are little more than a set of instructions that rely exclusively on external programs to do the actual work. This differs fundamentally from programming languages like Perl, which use internal language features instead of external programs. Shell scripting is based on the principle of using various simple programs to produce a complicated result.

Shell scripting is a useful tool for creating a stopgap solution for a problem in a few minutes using existing tools instead of having to re-invent the wheel by developing a program of your own. In this way, shell scripting has its strengths and weaknesses like any other language: Shell scripts are easy to write if you have any programming experience at all and can save considerable development time by using programs that already have the functionality you need. On the downside, shell scripts are written for specific shells and are not very portable as a result. (According to an old saying, it is often easier to port an entire shell than a complicated script that relies heavily on the features of one particular shell) Likewise, shell scripts are not ideal for permanent solutions and are not really designed with security in mind. As with any other language, you should decide beforehand whether the benefits of shell scripting are enough to offset its downsides for your particular situation.

Shell scripts support all the essential features of any scripting language, including conditional statements, variables, loops, etc. Since a shell script is little more than a bunch of individual commands kludged to work together, all the functionality the script might use is available for individual commands as well. (although it is inconvenient to do things that way)

To run a shell script, navigate to the directory it is in and run “./<script name>” (e.g. ./shellscript.sh) Do not omit the period and forward slash at the beginning or the script will not work. Also, you may have to make scripts executable with chmod before you will be able to run them.

Read on for our table of Essential Terminal Commands!

Essential basic commands

Although there are hundreds of commands available for the terminal, the following table will introduce you to the most essential ones. Any portions of a command enclosed in < > brackets is a variable and should be replaced with what is specified between the brackets. For example, < file> indicates that a file should be designated.

Essential Terminal Commands

Command	Function	Usage
ls	Lists all files in a directory	“ls” (Use “ls -l” for detailed output) For those used to DOS or cmd.exe, “dir” is very similar.
cp	Copies a file or folder	“cp <source file/folder> <destination file/folder>” e.g. “cp file1 file2” or “cp folder1 folder2” The first file/folder in the command is the original file while the second one is the file/folder that will be created as a copy.
mv	Moves a file from one directory to another. Also works as a rename command	“mv </folder/file> </newfolder/file>” or “mv file1 file2” (this will rename file1 to file2)
cd	Change to a different directory	“cd <new directory>” Only a folder name is needed instead of a full path if the new directory is a sub-directory of the current folder. To move to the next highest directory, run “cd ..”
mkdir	Makes a new directory in the current folder	“mkdir <new directory name>”
rm	Removes a file or directory	“rm <file>” removes a file. To remove a directory, use “rm -r <directory>” . Beware of “rm -rf /”, as this command will delete everything if executed as root.
chmod	Changes file properties	Chmod assigns file properties based on numbers and letters. Using + will add a new property, while – will take it away. For example, “chmod +x <filename>” will make a file (like a shell script) executable. For a list of file properties, run “info chmod”.
chown	Changes ownership of a file or folder	“chown <owner>:<group> <file>” <owner> and <group> should be set to the new owner and group.
man	Shows a manual page that tells you how to use a program	“man <program name>” Sometimes, there is an “info <program name>” as well.
top	Shows real-time process information and system usage stats	“top” To exit top, press Q.
cat	Concatenation tool used to join plain text files together	“cat <file1> <file2>” Cat is often used to preview individual files, but this is not really what it is for. (use less instead)
ps	Shows process information for a user	“ps -u <user>” e.g. “ps -u root” Sort of like top, but good for when you don't want or need real-time info. This command is best used with a grep pipeline to help you find a specific process.
kill	Forcefully terminates a process	“kill <process ID>” The process ID of the program you want to kill can be determined by running ps or top as shown above. If a program will not terminate with the normal kill command, “kill -9 <process ID>” will stop it for sure.
sudo	Executes command as superuser/root	“sudo <program>”
su	Escalates to a root shell	“su”
less	View an individual text file	“less <filename>” The up and down arrows allow you to scroll through the file. To return to the shell, press Q. Use this tool instead of cat when you want to look for individual files.
Grep	Searches for a text string	Grep is frequently used in pipelines, but “grep <pattern> <file>” can also be used to search for keywords in files.

openSUSE 11 Officially Released

Chris Moody — Fri, 20 Jun 2008 10:52:50 -0500

openSUSE 11 officially premiered yesterday with more than 200 new features specific to openSUSE and a redesigned installer that makes openSUSE even easier to install (and if you've ever installed it before, it was pretty darn easy then).

If you're into bling (and who doesn't like a little bling), there is the 3-D desktop app Compiz Fusion and it is now default in openSUSE 11.0. It includes a number of Compiz plugins, as well as easier configuration with Simple CompizConfig Settings Manager (CCSM) and the more comprehensive CompizConfig Settings Manager that lets you do detailed configuration of your Compiz setup.

Version 11 includes Gnome 2.22 and the KDE 4.0 desktop environments. KDE 4.0 doesn't include KDEPIM applications, so the openSUSE included beta versions of the KDEPIM suite (KMail, KOrganizer, Akregator, etc.) from the KDE 4.1 branch that is in development and slated to be released some time next month.

Firefox is of course the staple of Linux browsers but openSUSE 11 ships with the Firefox 3.0 beta 5 version. Updates will be available via the online update of course. Some other featured programs shipping with openSUSE are, Banshee 1.0, OpenOffice.org 2.4, NetworkManager 0.7, Wine 1.0 RC3, and Kepas for file sharing.

Ars technica calls this release a "very strong release" with many compelling improvements and "offers the best KDE 4 experience out there". They go on to say that it is no Ubuntu-killer, but we can expect to see a larger following for it in the coming months.

I'll be devoting part of my weekend to updating my openSUSE Linux box from v10 to v11. If you'd like to grab a download for your Linux box, it's available here.

Image Credit: openSUSE

Customize GNOME with Configuration Editor

Robert Strohmeyer — Fri, 31 Aug 2007 00:08:48 -0500

Whether you're a seasoned Linux user or a newb who's just switched from Windows, getting your Linux experience to run just the way you want it can be a time-consuming chore—especially if you do it by tweaking every app and setting individually. But with the GNOME Configuration Editor, you can tweak everything—from your OS interface to your individual apps—through a single, easy-to-use menu.

If you're running Ubuntu, Config Editor is not enabled by default. To enable it, go to System > Preferences > Main Menu, select System Tools from the left menu, and then put a checkmark next to Configuration Editor. Close the Main Menu editor and then run Configuration Editor from the Applications > System Tools menu.

If you've used RegEdit to edit the Windows system registry, the Configuration Editor interface should feel at least vaguely familiar to you almost immediately. In the left pane, you can select any of the various applications or GNOME features on your PC, and you can tweak the settings in the right pane.

As an example, I prefer to use CTRL+V to paste copied text into Terminal, rather than the default of Shift+CTRL+V. To tweak this setting, I click the arrow next to gnome-terminal in the left pane, and then select keybindings. In the right pane, I scroll down to paste and then highlight the key entry. I delete <shift> from the entry, and close the editor. The next time I want to paste into Terminal, CTRL+V will do the trick.

Once you get a feel for Configuration Editor, it becomes a convenient one-stop shop for all of your interface tweaks—whether you're editing settings for GNOME itself, or any of the apps you have installed.

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How to Customize Your Linux Desktop - From GTK to Compiz

Manipulating GTK Themes

Plasma Themes

Dealing with Common Theme-related Problems

Desktop Compositing

Compiz Fusion Overview

Working with Compiz Fusion

Emerald Overview

Creating Emerald Themes

Desktop Widgets

Screenlets

Plasma Widgets

SuperKaramba

The Complete Beginner's Guide to Linux

Table of Contents:

The Beginner's Guide to Linux Part 4: Introduction to the Terminal

Part 4: Introduction to the Terminal

Overview of the Linux Terminal

Basic Terminal Concepts

Switches

Wildcards

Program targets

Working with Input and Output

Joining commands together

Pipelines

Output Redirection

Shell Scripting Concepts

Essential basic commands

openSUSE 11 Officially Released

Customize GNOME with Configuration Editor