What are Emacs, Epoch, Latex, and Tex?

Emacs is the most versatile editor in the world. It is primarily for editing straight ASCII text but many useful programs have been written to enable interfacing with other software including Mathematica, L^ATEX, UNIX Mail, and the C, Fortran, and Pascal language compilers. Over half of all users of UNIX systems use Emacs or one of its many variants. This document explains the UTEP Math Department implementation of Epoch, the X Windows based version of Emacs. The term Emacs will be used throughout this document to refer to both Emacs and Epoch. The term Epoch will be used when referring specifically to features unavailable in ordinary Emacs. For more information about the Free Software Foundation (FSF) and the creator of Emacs, Richard Stallman, read the files GNU, INTERVIEW and MOTIVATION in the /usr/local/gnu/epoch/etc directory, or do C-h g. The following is a very simplified discussion of the relationship between Emacs, Epoch, Latex, and Tex.

1.

Emacs is an ASCII (Pronounced as-key) word processor. ASCII files are called text files. This essentially means that only the standard keyboard characters are allowed in the file. Epoch is a OpenWindows based version of Emacs used on a UNIX platform on our Sun Network.

2.

Any text file can be viewed on the screen by double clicking on the file from the file manager. If strange characters appear on your screen, the file is not a text file. A file test.tex can also be viewed in a window with a unix prompt by using the command: cat test.tex. Use cat test.tex | more to use the space bar to page thru a long file.

3.

Our Tex is a version of Knuth's mathematical typesetting program designed to be run on a unix platform. The output from a Tex compilation is used by a device specific driver program, to print mathematical text on an output device. The device free filename has a dvi extension.

4.

Think of Tex as a low level programming language like assembler language. You can program directly in assembler language. However, this would be tedious and complex.

5.

Latex is a high level programming language (say, like Fortran or C). You write your file in the syntax acceptable by Latex, i.e. your file is a Latex program. The Latex compiler then operates on your file to produce a file which is in the correct Tex syntax. A quick look at Latex commands can be found in Section 7. Examples of Latex Math Expressions can be found in the appendix sections 9.1 and 9.4. Sample letters are given in the appendix section 9.3. AMSLATEX is an alternative to Latex.

6.

You then run Tex on the output of the Latex compiler to produce a device free file called a DVI (has extension dvi) file.

7.

The DVI file is used by different device drivers to produce output, say on the screen, or printed output on a laser printer. For example, a file with an .ps (postscript) extension is a file which is ready to be printed on our laser (postscript) printers in BH 121 or BH 215.