In a Texinfo file, the commands that tell TeX how to typeset the
printed manual and tell makeinfo and
texinfo-format-buffer how to create an Info file are preceded
by `@'; they are called @-commands. For example,
@node is the command to indicate a node and @chapter
is the command to indicate the start of a chapter.
Please note: All the @-commands, with the exception of the
@TeX{}command, must be written entirely in lower case.
The Texinfo @-commands are a strictly limited set of constructs. The strict limits make it possible for Texinfo files to be understood both by TeX and by the code that converts them into Info files. You can display Info files on any terminal that displays alphabetic and numeric characters. Similarly, you can print the output generated by TeX on a wide variety of printers.
Depending on what they do or what arguments(4) they take, you need to write @-commands on lines of their own or as part of sentences:
@noindent at the beginning of a line as
the only text on the line. (@noindent prevents the beginning of
the next line from being indented as the beginning of a
paragraph.)
@chapter at the beginning of a line
followed by the command's arguments, in this case the chapter title, on
the rest of the line. (@chapter creates chapter titles.)
@dots{} wherever you wish but usually
within a sentence. (@dots{} creates dots ...)
@code{sample-code} wherever you
wish (but usually within a sentence) with its argument,
sample-code in this example, between the braces. (@code
marks text as being code.)
@example at the beginning of a line of
its own; write the body-text on following lines; and write the matching
@end command, @end example in this case, at the
beginning of a line of its own after the body-text. (@example
... @end example indents and typesets body-text as an
example.)
As a general rule, a command requires braces if it mingles among other
text; but it does not need braces if it starts a line of its own. The
non-alphabetic commands, such as @:, are exceptions to the rule;
they do not need braces.
As you gain experience with Texinfo, you will rapidly learn how to write the different commands: the different ways to write commands make it easier to write and read Texinfo files than if all commands followed exactly the same syntax. (For details about @-command syntax, see section @-Command Syntax.)