By convention, the name of a Texinfo file ends with (in order of preference) one of the extensions .texinfo, .texi, .txi, or .tex. The longer extensions are preferred since they describe 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 good printed manual and other output formats, 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 the Texinfo source with a line like this:
Here’s an explanation:
@setfilenameline provides a name for the Info file and tells TeX to open auxiliary files. All text before
@settitleline specifies a title for the page headers (or footers) of the printed manual, and the default title and document description for the ‘<head>’ in HTML. Strictly speaking,
@settitleis optional—if you don’t mind your document being titled ‘Untitled’.
@byeline at the end of the file on a line of its own tells the formatters that the file is ended and to stop formatting.
If you use Emacs, it is also useful to 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-*- @c %**start of header @setfilename info-file-name @settitle name-of-manual @c %**end of header
In the first line, ‘-*-texinfo-*-’ causes Emacs to switch into Texinfo mode when you edit the file.
@c ...header lines above which surround the
@settitle lines allow you to process,
within Emacs, just part of the Texinfo source. (See Start of Header.)
Furthermore, you will usually provide a Texinfo file with a title page, indices, and the like, all of which are explained in this manual. But the minimum, which can be useful for short documents, is just the three lines at the beginning and the one line at the end.