A host of miscellany is available for Linux, as one would expect from such a hodgepodge operating system. Linux's primary focus is currently for personal UNIX computing, but this is rapidly changing. Business and scientific software is expanding, and commercial software vendors are beginning to contribute to the growing pool of applications.
Several relational databases are available for Linux, including Postgres, Ingres, and Mbase. These are full-featured, professional client/server database applications similar to those found on other UNIX platforms. /rdb, a commercial database system, is available as well.
Scientific computing applications include FELT (a finite element analysis tool); gnuplot (a plotting and data analysis application); Octave (a symbolic mathematics package, similar to MATLAB); xspread (a spreadsheet calculator); xfractint, an X-based port of the popular Fractint fractal generator; xlispstat (a statistics package), and more. Other applications include Spice (a circuit design and analysis tool) and Khoros (an image/digital signal processing and visualization system).
Of course, there are many more such applications which have been, and can be, ported to run on Linux. Whatever your field, porting UNIX-based applications to Linux should be quite straightforward. Linux provides a complete UNIX programming interface, sufficient to serve as the base for any scientific application.
As with any operating system, Linux has its share of games. These include classic text-based dungeon games such as Nethack and Moria; MUDs (multi-user dungeons, which allow many users to interact in a text-based adventure) such as DikuMUD and TinyMUD; as well as a slew of X games such as xtetris, netrek, and Xboard (the X11 version of gnuchess). The popular shoot-em-up arcade-style Doom has also been ported to Linux.
For audiophiles, Linux has support for various sound cards and related software, such as CDplayer (a program which can control a CD-ROM drive as a conventional CD player, surprisingly enough), MIDI sequencers and editors (allowing you to compose music for playback through a synthesizer or other MIDI-controlled instrument), and sound editors for digitized sounds.
Can't find the application you're looking for? The Linux Software Map, described in Appendix A, contains a list of many software packages which have been written and ported to Linux. While this list is far from complete, it contains a great deal of software. Another way to find Linux applications is to look at the INDEX files found on Linux FTP sites, if you have Internet access. Just by poking around you'll find a great deal of software just waiting to be played with.
If you absolutely can't find what you need, you can always attempt to port the application from another platform to Linux. Most freely distributable UNIX-based software will compile on Linux with few problems. Or, if all else fails, you can write the application yourself. If it's a commercial application you're looking for, there may be a free ``clone'' available. Or, you can encourage the software company to consider releasing a Linux binary version. Several individuals have contacted software companies, asking them to port their applications to Linux, and have met with various degrees of success.