Texinfo

Texinfo is a documentation system and markup language used by the GNU Project to produce comprehensive software manuals. It relies on a single source file to generate both online documentation and printed output, allowing authors to maintain one authoritative document for multiple formats.

The Texinfo language uses a lightweight markup with commands prefixed by the at symbol, such as @chapter, @section, @node, and @menu, to structure documents. It supports cross-references, indices, and navigational structures. The standard toolchain includes texi2any (formerly makeinfo) to convert Texinfo sources into Info files for the GNU Info reader, as well as HTML, PDF, PostScript, and DVI output.

Texinfo originated in the 1980s, created by Richard Stallman as part of the GNU project to unify GNU documentation and ensure free distribution. It aims to provide consistent online and printed manuals from a single source, reducing the need for separate formatting ecosystems. It remains a core component of GNU documentation workflows and is used for manuals in many GNU projects.

An advantage of Texinfo is the ability to generate multiple formats from a single source, enabling updates to be reflected across all outputs. The format is designed to be readable in its source form while being machine-processable for output generation. Texinfo continues to be maintained within the GNU ecosystem and remains a foundational tool for producing free software manuals.