spreadsheet programs and how they work to a step-by-step guide on how to use teapot.

Like sc and xspread, the teapot spreadsheet is a space-saving way to handle spreadsheet data on your computer. You can find a copy of the teapot spreadsheet at

ftp://cantor.informatik.rwth-aachen.de/pub/unix/teapot-0.9.tar.gz

If you'd just like a little information about teapot, browse to

http://cantor.informatik.rwth-aachen.de/~michael/projects/teapot-en.html

Finding and Using the Shareware Wingz Spreadsheet

The Wingz spreadsheet, from Investment Intelligence Systems Corporation, is a shareware program you can evaluate, use for 45 days, and then pay a registration fee, or discard. Unlike many shareware programs, this is as capable a spreadsheet program as many commercial offerings.

Also, unlike sc, xspread, or teapot, this program requires about six megabytes of hard drive space when installed. You'll find nearly any feature you could need in a spreadsheet program, including a built-in scripting language called HyperScript. You can use HyperScript to build custom interfaces and programs to present your spreadsheet data. You won't find much documentation, but there are some impressive example sheets you can load and examine, and Wingz has built-in, context-sensitive help.

After you install Wingz, you can run the program after first defining the environment variable, WINGZ. To do this you can define the program at the command line with

# WINGZ=/pathwhereWingzisinstalled/Wingz ; export WINGZ

# $WINGZ/bin/Wingz

The first line defines the WINGZ environment variable to point to the Wingz directory, and the second runs the spreadsheet program. The actual application, Wingz, is found in the bin directory under the Wingz directory. You can also run one of two shell scripts included in the Wingz distribution to temporarily set the WINGZ variable.

The Wingz spreadsheet (see Figure 17.4) imports and exports a variety of well-known spreadsheet file formats, such as Lotus 1.a and 2.0, DIF, text, and SYLK.

You can generate many different types of 3D graphics, and spreadsheets may be linked, or previewed before printing. To read more about Wingz, or to get a copy, browse to

http://wingz.iisckc.com

Commercial Features of the Applixware Spreadsheet Program

Figure 17.4.
The Wingz spreadsheet
offers graphics and
desktop publishing
capability for Linux.

The Applixware spreadsheet program (see Figure 17.5) is part of the commercial Applixware suite of 10 programs for Linux (see Hour 14, "Text Processing" for more information). This spreadsheet program is integrated with the other Applixware programs using linked objects. This means that if you change the data in your spreadsheet file, the data or chart used in a word processing document will also change.

As you might expect with a commercial program, this spreadsheet offers all of the features of competing titles. Besides such features as integration with the other programs in its suite, print previews, or 3D graphics, this spreadsheet program has drag-and-drop cell movement, multiple views, and numerous database functions.

You can import and export many different types of spreadsheet formats, as shown in Table 17.1.

Table 17.1. Applixware spreadsheet import and export formats.

You can find out more about the Applix spreadsheet program by browsing to

Figure 17.5.
The Applixware
spreadsheet has
mouse-driven toolbars,
style sheets, and
supports multiple
graphics.

http://www.redhat.com

Using gnuplot to Graph Mathematical Formulas

This section shows you how to use gnuplot, an interactive plotting program by Thomas Williams and Colin Kelley. This program supports nearly 40 different printers and output devices, although you'll probably want to experiment with gnuplot using the X Window System, and print your graphics using PostScript (see Hour 15, "Preparing Documents," for more information on how to do this).

Although gnuplot (no relation to GNU software, but supported and distributed by the Free Software Foundation under the GNU General Public License) is not the only mathematical modeling and plotting program available for Linux, it is included on your CD-ROM. You'll find the gnuplot program under the /usr/bin directory.

The gnuplot program (see Figure 17.6) is a complete, interactive plotting program, and was originally designed to graph math functions and data. In this regard it is somewhat similar to other commercial formula-interpretation and plotting programs. It can read and save files, and has built-in help, so you can query the program while you use it.

Using gnuplot is simple. The program has five different command-line options, but many aspects of the program may be controlled interactively or as commands in a loaded gnuplot data file. One common use of the command-line option may be to control the point size (in pixels) of drawing lines using the -pointsize option, as in the following example:

# gnuplot -pointsize 2

You can use and plot many types of mathematical expressions, and according to the gnuplot documentation, any C, Pascal, FORTRAN, or BASIC language mathematical statement may be used. For example, Figure 17.6 shows a graphic plot of the expression (x*y)-(x+y).

Figure 17.6.
The gnuplot program
can help you visualize
mathematical formulas
or spreadsheet data.

Once you have finished, type quit to exit the program.

You can find more documentation, the gnuplot FAQ, and updates to the gnuplot program at

http://www.cs.dartmouth.edu/gnuplot_info.html

Tips

Many, many different financial and math applications are available for Linux. This hour has barely scratched the surface. You'll find financial applications that can help you manage investment portfolios, track stock prices, or aid in developing cost estimates for construction projects. You'll also find hundreds of specialized programs you can use in solving special computing needs for other sciences. One of the best sites for perusing some of the best of these applications is

http://SAL.KachinaTech.COM/

You'll also find a number of financial tools for Linux, along with source code, at

http://sunsite.unc.edu/pub/Linux/apps/financial