2. Some Definitions

As mentioned in the introduction, LaTeX is a language, so you can't simply start typing and expect to see your document appear before your very eyes[Why is TeX not a WYSIWYG system?]. You need to know a few things before you can get started, so it's best to define a few terms first. Don't worry if there seems a lot to take in, there will be some practical examples later, which should hopefully make things a little clearer.

Throughout this document, source code is illustrated in the form:

This is an \textbf{example}.

The corresponding output (how it will appear in the PDF document)^2.1 is illustrated like this:

Take care not to confuse a backslash \ with a forward slash / as they have different meanings. (Commands typeset in blue, such as \par, indicate a hyperlink to the command definition in the summary.)

Command definitions are shown in a typewriter font in the form:

\documentclass[<options>]{<class file>}

In this case the command being defined is called \documentclass and text typed <like this> (such as <options> and <class file>) indicates the type of thing you need to substitute. (Don't type the angle brackets!) For example, if you want the scrartcl class file you would substitute <class file> with scrartcl and if you want the letterpaper option you would substitute <options> with letterpaper, like this:

\documentclass[letterpaper]{scrartcl}

But more on that later.

Sometimes it can be easy to miss a space character when you're reading this kind of document. When it's important to indicate a space, the visible space symbol ␣ is used. For example:

A␣sentence␣consisting␣of␣six␣words.

When you type up the code, replace any occurrence of ␣ with a space.

One other thing to mention is the comment character % (the percent symbol). Anything from the percent symbol up to, and including, the end of line character is ignored by LaTeX. Thus

A simple % next comes a command to make some bold text
\textbf{example}

will produce the output

The percent symbol is often used to suppress unwanted space resulting from line breaks^2.2 in the source code . For example, the following code

Foo%
Bar

will produce the output:

as opposed to

Foo
Bar

which will produce the output:

On the other hand, spaces at the start of a line of input are ignored, so

Foo%
Bar

still produces:

Footnotes

... document)^2.1: This HTML version of the book uses bitmaps to illustrate the output, which doesn't look as good as the actual PDF version.
... breaks ^2.2: LaTeX treats the end-of-line character as a space.

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This book is also available as A4 PDF or 12.8cm x 9.6cm PDF or paperback (ISBN 978-1-909440-00-5).