## What a Texinfo File Must Have

By convention, the names of Texinfo files end with one of the extensions `.texinfo', `.texi', or `.tex'. The longer extension is preferred since it describes more clearly to a human reader the nature of the file. The shorter extensions are for operating systems that cannot handle long file names.

In order to be made into a printed manual and an Info file, a Texinfo file must begin with lines like this:

```\input texinfo
@setfilename info-file-name
@settitle name-of-manual
```

The contents of the file follow this beginning, and then you must end a Texinfo file with a line like this:

```@bye
```

The `\input texinfo' line tells TeX to use the `texinfo.tex' file, which tells TeX how to translate the Texinfo @-commands into TeX typesetting commands. (Note the use of the backslash, `\'; this is correct for TeX.) The `@setfilename' line provides a name for the Info file and tells TeX to open auxiliary files. The `@settitle' line specifies a title for the page headers (or footers) of the printed manual.

The `@bye` line at the end of the file on a line of its own tells the formatters that the file is ended and to stop formatting.

Usually, you will not use quite such a spare format, but will include mode setting and start-of-header and end-of-header lines at the beginning of a Texinfo file, like this:

```\input texinfo   @c -*-texinfo-*-
The `@c` lines which surround the `@setfilename' and `@settitle' lines are optional, but you need them in order to run TeX or Info on just part of the file. (See section Start of Header, for more information.)