**T _{E}X** (usually written

TeX is generally considered to be the best way to typeset complex mathematical formulas, but, especially in the form of LaTeX and other template packages, is now also being used for many other typesetting tasks. It can be used to compose mathematical expressions on Wikipedia pages; see Wikipedia:TeX markup.

Table of contents |

2 The typesetting system 3 License 4 Quality 5 The name 6 Derived works 7 Compatible tools 8 TeX and Wikipedia 9 TeX examples |

Guy Steele happened to be at Stanford during the summer of 1978, when Knuth was developing his first version of TeX. When he returned to MIT that fall, he rewrote TeX's I/O to run under ITS.

The first version of TeX was written in the SAIL programming language to run on a PDP-10 under Stanford's WAITS operating system. For later versions of TeX, Knuth invented the concept of literate programming, a way of producing compilable source code and high quality cross-linked documentation (typeset in TeX of course) from the same original file. The language used is called WEB and produces programs in Pascal.

TeX has an idiosyncratic version numbering system. Since version 3, updates have been indicated by adding an extra digit at the end of the decimal, so that the version number asymptotically approaches pi. The current version is 3.14159. This is a reflection of the fact that TeX is now very stable, and only minor updates are anticipated.

The TeX system has precise knowledge of the sizes of all characters and symbols, and using this information, it computes the optimal arrangement of letters per line and lines per page. It then produces a DVI file (for "device independent") containing the final locations of all characters. This dvi file can be printed directly given an appropriate printer driver, or it can be converted to other formats.

The ultimate reference works for TeX are the first two volumes of Knuth's Computers and Typesetting, *The TeXbook* and *TeX: The Program* (which includes the complete documented source code for TeX).

Knuth offers monetary awards to people who find and report a bug in it. The award per bug started at one cent and doubled every year until it was frozen at its current value of $327.68. This has not made Knuth poor, however, as there have been very few bugs and in any case a cheque proving that the owner found a bug in TeX is usually framed instead of cashed.

The name is properly typeset with the "E" below the baseline; systems that do not support subscript layout use the approximation "TeX". Fans like to proliferate names from the word "TeX" - such as TeXnician (user of TeX software), TeXhacker (TeX programmer), TeXmaster (competent TeX programmer), TeXhax, and TeXnique.

- LaTeX (Lamport TeX), which incorporates document styles for books, letters, slides, etc., and adds support for referencing and automatic numbering of sections and equations,
- AMS-TeX, produced by the American Mathematical Society, this has a lot of more user-friendly commands, which can be altered by journals to fit with the house style. Most of the features of AMS-Tex can be used in LaTeX by using the AMS "packages". This is then referred to as AMS-LaTeX. The main AMS-TeX manual is entitled
*The Joy of TeX*. - jadeTeX which uses TeX as a backend for printing from James' DSSSL Engine,
- Texinfo, the GNU documentation processing system.

The example fragments of TeX below are rendered using Texvc, and simple ones such as $\backslash \backslash frac\{a\}\{b\}$ can be used to generate , although it is recommended that one writes the HTML-rendered a/b instead.

hello \\byeThen open a command line interpreter and type

tex myfile.texTeX then creates a file

yap myfile.dviThe viewer shows

The dvi file can either be printed directly from the viewer or converted to a more common format such as PostScript using the `dvips` program.

To see TeX further in action, look at its formatting of mathematical formulas. For example, to write the well-known quadratic formula, try entering

The quadratic formula is ${-b\\pm\\sqrt{b^2-4ac} \\over {2a}}$ \\byeUse TeX as above, and you should get something that looks like

- The quadratic formula is

The quadratic formula is $${-b\\pm\\sqrt{b^2-4ac} \\over {2a}}$$ \\byerenders as

- The quadratic formula is

- The T
_{E}X users group: http://www.tug.org/ - Comprehensive T
_{E}X Archive Network: http://www.ctan.org/ . Repository of the T_{E}X source and hundreds of add-ons and style files. - The LaTeX project: http://www.latex-project.org/ .
- Donald E. Knuth,
*The T*(Computers and Typesetting Volume A), Reading, Massachusetts: Addison-Wesley, 1984. ISBN 0201134489._{E}Xbook - Norman Walsh,
*Making TeX Work*, http://makingtexwork.sourceforge.net/mtw/index.html Free online book - Omega (16 bit version of TeX; use
*lambda*, not*omega*on the command line!)