Anybody who has looked at Linux documentation on the command line would know about man pages, and quite likely about GNU info as well. The GNU project invented the “info” system as a (supposedly) superior replacement for man pages, but for some reason it never became that popular. I personally find it quite annoying to use, and it’s clear I’m not the only one. The GNU info system requires documentation to be written in Texinfo format, from which it can be generated in other formats displayable with the info command as well as other means. Now at least one GNU project, namely Emacs <http://lwn.net/Articles/625072/>, is contemplating moving away from maintaining its documentation in Texinfo format. The suggestion is to use AsciiDoc instead. This is one of a raft of newer, simpler markup formats that are designed so that even the source can be read and understood by ordinary humans, since the appearance of many of the markup sequences already gives some indication of their function in the layout. You may also have heard of Markdown (GitHub uses a flavour of this) and reStructedText (understood by Docutils/Sphinx, the standard toolset for Python documentation)--these are variations on the same idea. The LWN article has an error in it, though: the AsciiDoc package itself is not constrained to only generating HTML, it can output (shudder) DocBook SGML as well. And then there is another piece of software called Pandoc, which can convert between a whole range of different formats, including AsciiDoc.