GNU Info

(texinfo)Info Files

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Enter node , (file) or (file)node

Info files
==========

  An Info file is a Texinfo file formatted so that the Info
documentation reading program can operate on it.  (`makeinfo' and
`texinfo-format-buffer' are two commands that convert a Texinfo file
into an Info file.)

  Info files are divided into pieces called "nodes", each of which
contains the discussion of one topic.  Each node has a name, and
contains both text for the user to read and pointers to other nodes,
which are identified by their names.  The Info program displays one node
at a time, and provides commands with which the user can move to other
related nodes.

  Note: info, for more information about using Info.

  Each node of an Info file may have any number of child nodes that
describe subtopics of the node's topic.  The names of child nodes are
listed in a "menu" within the parent node; this allows you to use
certain Info commands to move to one of the child nodes.  Generally, an
Info file is organized like a book.  If a node is at the logical level
of a chapter, its child nodes are at the level of sections; likewise,
the child nodes of sections are at the level of subsections.

  All the children of any one parent are linked together in a
bidirectional chain of `Next' and `Previous' pointers.  The `Next'
pointer provides a link to the next section, and the `Previous' pointer
provides a link to the previous section.  This means that all the nodes
that are at the level of sections within a chapter are linked together.
Normally the order in this chain is the same as the order of the
children in the parent's menu.  Each child node records the parent node
name as its `Up' pointer.  The last child has no `Next' pointer, and the
first child has the parent both as its `Previous' and as its `Up'
pointer.(1) (Note: Info Files-Footnote-1)

  The book-like structuring of an Info file into nodes that correspond
to chapters, sections, and the like is a matter of convention, not a
requirement.  The `Up', `Previous', and `Next' pointers of a node can
point to any other nodes, and a menu can contain any other nodes.
Thus, the node structure can be any directed graph.  But it is usually
more comprehensible to follow a structure that corresponds to the
structure of chapters and sections in a printed book or report.

  In addition to menus and to `Next', `Previous', and `Up' pointers,
Info provides pointers of another kind, called references, that can be
sprinkled throughout the text.  This is usually the best way to
represent links that do not fit a hierarchical structure.

  Usually, you will design a document so that its nodes match the
structure of chapters and sections in the printed output.  But
occasionally there are times when this is not right for the material
being discussed.  Therefore, Texinfo uses separate commands to specify
the node structure for the Info file and the section structure for the
printed output.

  Generally, you enter an Info file through a node that by convention is
named `Top'.  This node normally contains just a brief summary of the
file's purpose, and a large menu through which the rest of the file is
reached.  From this node, you can either traverse the file
systematically by going from node to node, or you can go to a specific
node listed in the main menu, or you can search the index menus and then
go directly to the node that has the information you want.
Alternatively, with the standalone Info program, you can specify
specific menu items on the command line (Note: Top.).

  If you want to read through an Info file in sequence, as if it were a
printed manual, you can hit <SPC> repeatedly, or you get the whole file
with the advanced Info command `g *'.  (*note Advanced Info commands:
(info)Expert.)

  The `dir' file in the `info' directory serves as the departure point
for the whole Info system.  From it, you can reach the `Top' nodes of
each of the documents in a complete Info system.

  If you wish to refer to an Info file in a URI, you can use the
(unofficial) syntax exemplified in the following.  This works with
Emacs/W3, for example:
     info:///usr/info/emacs#Dissociated%20Press
     info:emacs#Dissociated%20Press
     info://localhost/usr/info/emacs#Dissociated%20Press

  The `info' program itself does not follow URI's of any kind.