GeekTool was released as a free download on the Mac App Store a few weeks ago, and it's remained at the top of the download chart since. It's been around for years, and we've featured it a couple of times on TUAW, but the MAS release allows it to reach a new audience.
Unlike the GeekTool of yore, the MAS version is not a preference pane, but a separate app. It allows users to display various information on their desktops via three plug-ins: file, shell and image. These are referred to as geeklets and can be used as follows:
- File: It displays live content from any file. It's mostly used to monitor system or application activity.
- Shell: This displays the output of any Unix shell command and is the root of a lot of the customizations in the program.
- Image: Originally developed to display monitoring graphs, it's also used for image customization.
As the product description warns, this isn't for general Mac users, but those who are comfortable with Unix and shell commands. Drag one of the plug-ins to the desktop, then customize it for your personal use. There's a lot of scripts to choose from out there. This piece from Lifehacker will help get you started and Mac OS X Tips has a comprehensive list of geeklets. You can use GeekTool to monitor everything from time and date wherever you want to pulling your RSS feed and displaying the album cover of your current iTunes track.
While it's not for the brand-new Mac user, or for the faint of heart, GeekTool is good to see if you're interested in learning more about the underpinnings of your Mac.