Mac OS X and Unix both have, at their cores, a command line. And just as Apple placed the glossy Aqua user interface atop OS X, opensource programmers have designed the K Desktop Environment (KDE) to give Unix a useful windowed interface. But while Unix users can't get Aqua without buying a Mac, any Mac user can use KDE. It just takes an adventurous spirit and a little ingenuity.

Why place a Unix-based windowed environment on top of Aqua (which is, after all, a Unix-based windowed environment)? Partly for the experience of stretching your Mac to its limits, but also because doing so lets you run many open-source and free alternatives to Mac applications.

Gather Your Gear

To run KDE, you'll need to install some other software. First, you'll need X11 (see "X11 Marks the Spot," Geek Factor, December 2003), which allows Unix machines to run graphical-interface programs and lets you control those programs with a mouse. Check to see whether X11 is already installed by looking for it in Applications: Utilities. If it's not there, you'll need to run the installer located on Panther Install Disc 3, in Packages: X11 User.pkg. (X11 runs only on Panther.)

You'll also need to install Apple's developer, or Xcode, tools from the Mac OS X Xcode Tools disc that comes with Panther. You can also download the tools by signing up for a free developer account at http://connect.apple.com.

The last thing you'll need is Fink, an add-on Unix program that allows you to download, install, and update programs. This is also a free download, available at http://fink.sourceforge.net/download.

To use the newest revision of KDE, you have to tell Fink to recognize so-called unstable packages. (A package is usually deemed unstable if the application hasn't been extensively tested. At press time, there was still no firm date for a version of Fink that would support a stable KDE 3.2.) To do this, use pico, a Unix text editor, to edit the fink.conf file. First, make sure you're using an administrator account. Then open Terminal and type sudo pico /sw/etc/fink.conf at the command prompt. Enter your password.

Using your arrow keys to move the cursor, add unstable/main and unstabl e/crypto to the end of the line beginning with Trees:. Once that's done, press control-O and then press enter to save the changes; press control-X to exit pico.

Back at the shell prompt in the Terminal window, make sure you're running the latest version of Fink by typing fink selfupdate-rsync. If you're connected to the Internet, Fink will search for newer versions. If it finds anything, let it install everything before you go on to the next step. (This may take a while, so plan on doing it during lunch or overnight.)

When the update is done, you have to edit the sources.list file to instruct another Unix program that Fink installs, apt-get, to download precompiled binaries of KDE. (These are readily available only from one particular server.) In Terminal, type sudo pico /sw/etc/apt/sources.1ist. Then add the following lines of code to the end of the file paths inside that file:

Save the changes by pressing control-O, and then press control-X to return to Terminal's command prompt.

Now you're ready to download and install KDE itself. In Terminal type sudo apt-get update; sudo apt-get install bundl e-kde. This allows Fink to update apt-get, which you'll use to simplify the process of acquiring Unix applications later. The command also instructs Fink to download KDE.

The 279MB file may take a bit of time to download, depending on your computer's speed and Internet connection. Once it's downloaded and installed, and you find yourself back to a command prompt, you'll need to add one more thing.

Run, KDE, Run!

If all went well, KDE should open when you launch X11. On slower Macs, KDE might take a few minutes to start up. Don't worry, something is happening.

Before you dive in, make a few adjustments to ensure that eveiything runs smoothly. First, turn off KDE's desktop icons, via its preferences, so you can use your normal OS X desktop. (If you don't, the KDE desktop will replace your usual OS X desktop-making it unusable.)

Click on the large K in the lower left corner of your screen to access a pop-up menu. Choose Settings: Control Center. Next, expand the Desktop menu. Under Behavior, deselect the Show Icons On Desktop option.

You'll see something resembling the Dock, which in KDE' is known as the Kicker. Since the Kicker is also at the bottom of the screen, you'll find it easier to use if you move the Dock somewhere else. Go to System Preferences: Dock to do this.

Prepare to Play

Now what? With KDE in place, you can run all kinds of free alternatives to various large commercial programs. Two of the most powerful examples are the Adobe Photoshop look-alike GIMP (www.gimp.org) and the Microsoft Office stand-in KOffice (www.koffice.org). (See "Image Editing on the Cheap.")

You can install GIMP in just a couple of steps. First, open KDE's version of Terminal, called Konsole, by clicking on the icon that sits between the wrench and house icons on the Kicker. Then type sudo apt-get install gimp.

The apt-get program is one of the most powerful things about Fink; it dramatically streamlines the process of installing apps that run in KDE. Once you type apt-get, you'll be prompted for the administrator password. If you're connected to the Internet, the program will download and install.

Once that's done, just type gimp in Konsole to launch GIMP. It's just as easy to install the Microsoft Word-compatible AbiWorcl word processor.

Open Konsole and type sudo apt-get install abiword. To find other programs that run under KDE, check out the Package Database site at http://fink.sf.net/pdb/.

Get Productive

As you explore, you might find that KDF,'s interface offers some advantages. For instance, I prefer to run another Office substitute, OpenOffice (www.openoffice.org), with KDE, instead of directly in Apple's X11. OpenOffice wasn't designed to make it easy to toggle between multiple documents at once, and KDE lets you get around this limitation by storing OpenOffice windows in the Kicker.

Also, since KDE has four virtual desktops, you can switch between different working environments with a single click. This comes in handy when you have many windows open and need a way to handle them all.

KDE is full of ways to both work hard and play hard. Take the time to experiment with it-the results may surprise you. Image Editing on the Cheap KDE lets you use free open-source programs, such as GIMP, a Photoshop alternative. It also gives you four virtual desktops (indicated by numbers in the Kicker), making organization a breeze.

Who says Unix geeks are all work and no play? Under the K menu, open the Toys folder to find the application called AMOR (Amusing Misuse of Resources). While this is running, you'll see small, animated icons-from a pair of wandering eyes to Tux, the penguin mascot of Linux-when you have KDE windows open. Click on Always On Top to make sure the animation comes up.

CYRUS FARIVAR is a lifelong Macworld reader. From January 2004 through his graduation from UC Berkeley in May 2004, he was an editorial intern at the magazine.