LaTeX/Introduction

What is TeX?
TeX is a language created by to typeset documents attractively and consistently. Knuth started writing the TeX typesetting engine in 1977 to explore the potential of the digital printing equipment that was beginning to infiltrate the publishing industry at that time, in the hope that he could reverse the trend of deteriorating typographical quality that he saw affecting his own books and articles. While TeX is a programming language in the sense that it is Turing complete, its main job is to serve as a markup language for describing how your document should look. The fine control TeX offers over document structure and formatting makes it a powerful and formidable tool. TeX is renowned for being extremely stable, for running on many different kinds of computers, and for being virtually bug free. The version numbers of TeX are converging toward the mathematical constant $$\pi$$, with the current version number being 3.1415926.

The name TeX is intended by its developer to be, /x/ being the velar fricative, the final consonant of loch and Bach. (Donald E. Knuth, The TeXbook) The letters of the name are meant to represent the capital Greek letters tau, epsilon, and chi, as TeX is an abbreviation of τέχνη (ΤΕΧΝΗ – technē), Greek for both "art" and "craft", which is also the root word of technical. English speakers often pronounce it, like the first syllable of technical.

The tools TeX offers "out of the box" are relatively primitive, and learning how to perform common tasks can require a significant time investment. Fortunately, document preparation systems based on TeX, consisting of collections of pre-built commands and macros, do exist. These systems save time by automating certain repetitive tasks; however, this convenience comes at the cost of complete design flexibility. One of the most popular macro packages is called LaTeX.

What is LaTeX?
LaTeX (pronounced either "Lah-tech" or "Lay-tech") is a set of macros for TeX created by. Its purpose is to simplify the TeX typesetting, especially for documents containing mathematical formulae. Within the typesetting system, its name is formatted as.

TeX is both a typographical and logical markup language, and one has to take account of both issues when writing a TeX document. In creating LaTeX, Lamport's aim was to split those two aspects. A typesetter can make a template and the writers can focus on LaTeX logical markup despite perhaps not know anything about typesetting.

In addition to the commands and options LaTeX offers, many other authors have contributed extensions, called packages or styles, which you can use for your documents. Many of these are bundled with most TeX/LaTeX software distributions; more can be found in the Comprehensive TeX Archive Network (CTAN).

Why should I use LaTeX?
Most readers will be familiar with WYSIWYG (What You See Is What You Get) typesetting systems such as, , or. Using LaTeX is fundamentally different from using these other programs—instead of seeing your document as it comes together, you describe how you want it to look using commands in a text file, then run that file through the LaTeX program to build the result. While this has the disadvantage of needing to pause your work and take multiple steps to see what your document looks like, there are many advantages to using LaTeX:


 * You can concentrate purely on the structure and contents of the document. LaTeX will automatically ensure that the typography of your document—fonts, text sizes, line heights, and other layout considerations—are consistent according to the rules you set.
 * In LaTeX, the document structure is visible to the user, and can be easily copied to another document. In WYSIWYG applications it is often not obvious how a certain formatting was produced, and it might be impossible to copy it directly for use in another document.
 * Indexes, footnotes, citations and references are generated easily and automatically.
 * Mathematical formulae can be easily typeset. (Quality mathematics was one of the original motivations of TeX.)
 * Since the document source is plain text,
 * Document sources can be read and understood with any text editor, unlike the complex binary and formats used with WYSIWYG programs.
 * Tables, figures, equations, etc. can be generated programmatically with any language.
 * Changes can be easily tracked with software.
 * Some academic journals only accept or strongly recommend submissions in the form of LaTeX documents. Publishers offer LaTeX templates.

When the source file is processed by the LaTeX program, or engine, it can produce documents in several formats. LaTeX natively supports and PDF, but by using other software you can easily create PostScript, PNG, JPEG, etc.

Terms regarding TeX
LaTeX is a document preparation system based on TeX. So the system is the combination of the language and the macros.
 * Document preparation systems:

TeX distributions are collections of packages and programs (compilers, fonts, and macro packages) that enable you to typeset without having to manually fetch files and configure things.
 * Distributions:

An engine is an executable that can turn your source code into a printable output format. The engine by itself only handles the syntax. It also needs to load fonts and macros to fully understand the source code and generate output properly. The engine will determine what kind of source code it can read, and what format it can output (usually DVI or PDF).
 * Engines:

All in all, distributions are an easy way to install what you need to use the engines and the systems you want. Distributions usually target specific operating systems. You can use different systems on different engines, but sometimes there are restrictions. Code written for TeX, LaTeX or ConTeXt are (mostly) not compatible. Additionally, engine-specific code (like font for XeTeX) may not be compiled by every engine.

When searching for information on LaTeX, you might also stumble upon, , or other names with a -TeX suffix. Let's recap most of the terms in this table.

What's next?
In the next chapter we discuss installing LaTeX on your system. Then we will typeset our first LaTeX file.

Learning more
One of the most frustrating things beginners and even advanced users might encounter using LaTeX is the difficulty of changing the look of your documents. While WYSIWYG programs make it trivial to change fonts and layouts, LaTeX requires you to learn new commands and packages to do so. Subsequent chapters will cover many common use cases, but know that this book is only scratching the surface.

Coming from a community of typography enthusiasts, most LaTeX packages contain excellent documentation. This should be your first step if you have questions—if a package's manual has not been installed on your machine as part of your TeX distribution, it can be found on CTAN.

Other useful resources include:
 * The TeX Stack Exchange Q&A
 * the #latex IRC channel on Freenode
 * The TeX FAQ
 * The LaTeX.org forums
 * Donald Knuth's original guide to TeX, The TeXbook
 * Leslie Lamport's original guide to LaTeX, LaTeX: A document preparation system

LaTeX/_Einleitung LaTeX/Увод لاتخ/مقدمة