The Texinfo system is a more recent development for program documentation than man pages, and it is the standard documentation format for many GNU programs (the GNU project is an important source of free software). It was designed so that the same file could be used to generate printed documentation with indexes as well as hyperlinked online documentation (Texinfo predates the web but works similarly). The most common tool for browsing Texinfo documentation is the info command, and Texinfo documentation is often referred to as info pages.
To see, for example, the info page for ls, type info ls. Naturally, info itself has info pages which can be displayed with info info. There are pages both about writing info documentation as well as browsing it. To learn about the ``stand-alone'' info browser type info info-stnd.
Example 11-2. Learning about the stand-alone info browser
File: info-stnd.info, Node: Top, Next: What is Info, Up: (dir) GNU Info ******** This file documents GNU Info, a program for viewing the on-line formatted versions of Texinfo files, version 4.1. This documentation is different from the documentation for the Info reader that is part of GNU Emacs. This manual is for Info version 4.1, updated 2 March 2002. * Menu: * What is Info:: What is Info? * Invoking Info:: Options you can pass on the command line. * Cursor Commands:: Commands which move the cursor within a node. * Scrolling Commands:: Commands for reading the text within a node. * Node Commands:: Commands for selecting a new node. * Searching Commands:: Commands for searching an Info file. * Xref Commands:: Commands for selecting cross references. * Window Commands:: Commands which manipulate multiple windows. * Printing Nodes:: How to print out the contents of a node. * Miscellaneous Commands:: A few commands that defy categories. * Variables:: How to change the default behavior of Info. * Custom Key Bindings:: How to define your own key-to-command bindings. * Index:: Global index containing keystrokes, command names, variable names, and general concepts. --zz-Info: (info-stnd.info.gz)Top, 31 lines --All-- Subfile: info-stnd.info-1.gz Welcome to Info version 4.1. Type C-h for help, m for menu item.
Info pages are browsed using different keys than man pages. As might be expected, PgDn and PgUp scroll by pages. Tab moves forward from one hyperlink to the next, and Esc-Tab moves backward through hyperlinks. The Enter key follows a hyperlink. Searching can be done with the s key and the last search is repeated with Ctrl-xn. Finally, pages are hierarchical, and u moves up one level of the hierarchy.