@c Copyright (C) 1996 John W. Eaton
@c This is part of the Octave manual.
@c For copying conditions, see the file gpl.texi.

@c This file is meant to be included in any arbitrary piece of
@c documentation that wishes to describe the info program.  Some day
@c info-stnd.texi should probably use this file instead of duplicating
@c its contents. 
@c
@c This file documents the use of the standalone GNU Info program,
@c versions 2.7 and later. 

@node Using Info, Copying, Command Line Editing, Top
@appendix Using Info

@menu
* Cursor Commands::             
* Scrolling Commands::          
* Node Commands::               
* Searching Commands::          
* Xref Commands::               
* Window Commands::             
* Printing Nodes::              
* Other Info Commands::         
* Info Variables::              
@end menu

@dfn{Info} is a program which is used to view info files on an ASCII
terminal. @dfn{info files} are the result of processing texinfo files
with the program @code{makeinfo} or with  the Emacs command @code{M-x
texinfo-format-buffer}.  Finally, @dfn{texinfo} is a documentation
language which allows a printed manual and on-line documentation (an
info file) to be produced from a single source file.

@menu
* Cursor Commands::	    Commands which move the cursor within a node.
* Scrolling Commands::	    Commands for moving the node around in a window.
* 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.
* Other Info Commands::     A few commands that defy categories.
* Info Variables::	    How to change the default behavior of Info.
@end menu

@node Cursor Commands, Scrolling Commands, Using Info, Using Info
@appendixsec Moving the Cursor
@cindex cursor, moving
Many people find that reading screens of text page by page is made
easier when one is able to indicate particular pieces of text with some
kind of pointing device.  Since this is the case, GNU Info (both the
Emacs and standalone versions) have several commands which allow you to
move the cursor about the screen.  The notation used in this manual to
describe keystrokes is identical to the notation used within the Emacs
manual, and the GNU Readline manual.  @xref{Characters, , Character
Conventions, emacs, the GNU Emacs Manual}, if you are unfamiliar with
the notation.

The following table lists the basic cursor movement commands in Info.
Each entry consists of the key sequence you should type to execute the
cursor movement, the @code{M-x}@footnote{@code{M-x} is also a command;
it invokes @code{execute-extended-command}.  @xref{M-x, , Executing an
extended command, emacs, the GNU Emacs Manual}, for more detailed
information.} command name (displayed in parentheses), and a short
description of what the command does.  All of the cursor motion commands
can take an @dfn{numeric} argument (@pxref{Other Info Commands,
@code{universal-argument}}), to find out how to supply them.  With a
numeric argument, the motion commands are simply executed that many
times; for example, a numeric argument of 4 given to @code{next-line}
causes the cursor to move down 4 lines.  With a negative numeric
argument, the motion is reversed; an argument of -4 given to the
@code{next-line} command would cause the cursor to move @emph{up} 4
lines.

@table @asis
@item @code{C-n} (@code{next-line})
@kindex C-n, in Info windows
@findex next-line
Moves the cursor down to the next line.

@item @code{C-p} (@code{prev-line})
@kindex C-p, in Info windows
@findex prev-line
Move the cursor up to the previous line.

@item @code{C-a} (@code{beginning-of-line})
@kindex C-a, in Info windows
@findex beginning-of-line
Move the cursor to the start of the current line.

@item @code{C-e} (@code{end-of-line})
@kindex C-e, in Info windows
@findex end-of-line
Moves the cursor to the end of the current line.

@item @code{C-f} (@code{forward-char})
@kindex C-f, in Info windows
@findex forward-char
Move the cursor forward a character.

@item @code{C-b} (@code{backward-char})
@kindex C-b, in Info windows
@findex backward-char
Move the cursor backward a character.

@item @code{M-f} (@code{forward-word})
@kindex M-f, in Info windows
@findex forward-word
Moves the cursor forward a word.

@item @code{M-b} (@code{backward-word})
@kindex M-b, in Info windows
@findex backward-word
Moves the cursor backward a word.

@item @code{M-<} (@code{beginning-of-node})
@itemx @code{b}
@kindex b, in Info windows
@kindex M-<, in Info windows
@findex beginning-of-node
Moves the cursor to the start of the current node.

@item @code{M->} (@code{end-of-node})
@kindex M->, in Info windows
@findex end-of-node
Moves the cursor to the end of the current node.

@item @code{M-r} (@code{move-to-window-line})
@kindex M-r, in Info windows
@findex move-to-window-line
Moves the cursor to a specific line of the window.  Without a numeric
argument, @code{M-r} moves the cursor to the start of the line in the
center of the window.  With a numeric argument of @var{n}, @code{M-r}
moves the cursor to the start of the @var{n}th line in the window.
@end table

@node Scrolling Commands, Node Commands, Cursor Commands, Using Info
@appendixsec Moving Text Within a Window
@cindex scrolling, in Info windows

Sometimes you are looking at a screenful of text, and only part of the
current paragraph you are reading is visible on the screen.  The
commands detailed in this section are used to shift which part of the
current node is visible on the screen.

@table @asis
@item @code{SPC} (@code{scroll-forward})
@itemx @code{C-v}
@kindex SPC, in Info windows
@kindex C-v, in Info windows
@findex scroll-forward
Shift the text in this window up.  That is, show more of the node which
is currently below the bottom of the window.  With a numeric argument,
show that many more lines at the bottom of the window; a numeric
argument of 4 would shift all of the text in the window up 4 lines
(discarding the top 4 lines), and show you four new lines at the bottom
of the window.  Without a numeric argument, @key{SPC} takes the bottom
two lines of the window and places them at the top of the window,
redisplaying almost a completely new screenful of lines.

@item @code{DEL} (@code{scroll-backward})
@itemx @code{M-v}
@kindex DEL, in Info windows
@kindex M-v, in Info windows
@findex scroll-backward
Shift the text in this window down.  The inverse of
@code{scroll-forward}.

@end table

@cindex scrolling through node structure
The @code{scroll-forward} and @code{scroll-backward} commands can also
move forward and backward through the node structure of the file.  If
you press @key{SPC} while viewing the end of a node, or @key{DEL} while
viewing the beginning of a node, what happens is controlled by the
variable @code{scroll-behaviour}.  @xref{Info Variables,
@code{scroll-behaviour}}, for more information.

@table @asis
@item @code{C-l} (@code{redraw-display})
@kindex C-l, in Info windows
@findex redraw-display
Redraw the display from scratch, or shift the line containing the cursor
to a specified location.  With no numeric argument, @samp{C-l} clears
the screen, and then redraws its entire contents.  Given a numeric
argument of @var{n}, the line containing the cursor is shifted so that
it is on the @var{n}th line of the window.

@item @code{C-x w} (@code{toggle-wrap})
@kindex C-w, in Info windows
@findex toggle-wrap
Toggles the state of line wrapping in the current window.  Normally,
lines which are longer than the screen width @dfn{wrap}, i.e., they are
continued on the next line.  Lines which wrap have a @samp{\} appearing
in the rightmost column of the screen.  You can cause such lines to be
terminated at the rightmost column by changing the state of line
wrapping in the window with @code{C-x w}.  When a line which needs more
space than one screen width to display is displayed, a @samp{$} appears
in the rightmost column of the screen, and the remainder of the line is
invisible.
@end table

@node Node Commands, Searching Commands, Scrolling Commands, Using Info
@appendixsec Selecting a New Node
@cindex nodes, selection of in Info windows

This section details the numerous Info commands which select a new node
to view in the current window.

The most basic node commands are @samp{n}, @samp{p}, @samp{u}, and
@samp{l}.

When you are viewing a node, the top line of the node contains some Info
@dfn{pointers} which describe where the next, previous, and up nodes
are.  Info uses this line to move about the node structure of the file
when you use the following commands:

@table @asis
@item @code{n} (@code{next-node})
@kindex n, in Info windows
@findex next-node
Selects the `Next' node.  

@item @code{p} (@code{prev-node})
@kindex p, in Info windows
@findex prev-node
Selects the `Prev' node.

@item @code{u} (@code{up-node})
@kindex u, in Info windows
@findex up-node
Selects the `Up' node.
@end table

You can easily select a node that you have already viewed in this window
by using the @samp{l} command -- this name stands for "last", and
actually moves through the list of already visited nodes for this
window.  @samp{l} with a negative numeric argument moves forward through
the history of nodes for this window, so you can quickly step between
two adjacent (in viewing history) nodes.

@table @asis
@item @code{l} (@code{history-node})
@kindex l, in Info windows
@findex history-node
Selects the most recently selected node in this window.
@end table

Two additional commands make it easy to select the most commonly
selected nodes; they are @samp{t} and @samp{d}.

@table @asis
@item @code{t} (@code{top-node})
@kindex t, in Info windows
@findex top-node
Selects the node @samp{Top} in the current info file.

@item @code{d} (@code{dir-node})
@kindex d, in Info windows
@findex dir-node
Selects the directory node (i.e., the node @samp{(dir)}).
@end table

Here are some other commands which immediately result in the selection
of a different node in the current window:

@table @asis
@item @code{<} (@code{first-node})
@kindex <, in Info windows
@findex first-node
Selects the first node which appears in this file.  This node is most
often @samp{Top}, but it doesn't have to be.

@item @code{>} (@code{last-node})
@kindex >, in Info windows
@findex last-node
Selects the last node which appears in this file.

@item @code{]} (@code{global-next-node})
@kindex ], in Info windows
@findex global-next-node
Moves forward or down through node structure.  If the node that you are
currently viewing has a @samp{Next} pointer, that node is selected.
Otherwise, if this node has a menu, the first menu item is selected.  If
there is no @samp{Next} and no menu, the same process is tried with the
@samp{Up} node of this node.

@item @code{[} (@code{global-prev-node})
@kindex [, in Info windows
@findex global-prev-node
Moves backward or up through node structure.  If the node that you are
currently viewing has a @samp{Prev} pointer, that node is selected.
Otherwise, if the node has an @samp{Up} pointer, that node is selected,
and if it has a menu, the last item in the menu is selected.
@end table

You can get the same behavior as @code{global-next-node} and
@code{global-prev-node} while simply scrolling through the file with
@key{SPC} and @key{DEL}; @xref{Info Variables, @code{scroll-behaviour}},
for more information.

@table @asis
@item @code{g} (@code{goto-node})
@kindex g, in Info windows
@findex goto-node
Reads the name of a node and selects it.  No completion is done while
reading the node name, since the desired node may reside in a separate
file.  The node must be typed exactly as it appears in the info file.  A
file name may be included as with any node specification, for example

@example
@code{g(emacs)Buffers}
@end example

finds the node @samp{Buffers} in the info file @file{emacs}.

@item @code{C-x k} (@code{kill-node})
@kindex C-x k, in Info windows
@findex kill-node
Kills a node.  The node name is prompted for in the echo area, with a
default of the current node.  @dfn{Killing} a node means that Info tries
hard to forget about it, removing it from the list of history nodes kept
for the window where that node is found.  Another node is selected in
the window which contained the killed node.

@item @code{C-x C-f} (@code{view-file})
@kindex C-x C-f, in Info windows
@findex view-file
Reads the name of a file and selects the entire file.  The command
@example
@code{C-x C-f @var{filename}}
@end example
is equivalent to typing
@example
@code{g(@var{filename})*}
@end example

@item @code{C-x C-b} (@code{list-visited-nodes})
@kindex C-x C-b, in Info windows
@findex list-visited-nodes
Makes a window containing a menu of all of the currently visited nodes.
This window becomes the selected window, and you may use the standard
Info commands within it.

@item @code{C-x b} (@code{select-visited-node})
@kindex C-x b, in Info windows
@findex select-visited-node
Selects a node which has been previously visited in a visible window.
This is similar to @samp{C-x C-b} followed by @samp{m}, but no window is
created.
@end table

@node Searching Commands, Xref Commands, Node Commands, Using Info
@appendixsec Searching an Info File
@cindex searching

GNU Info allows you to search for a sequence of characters throughout an
entire info file, search through the indices of an info file, or find
areas within an info file which discuss a particular topic.

@table @asis
@item @code{s} (@code{search})
@kindex s, in Info windows
@findex search
Reads a string in the echo area and searches for it.

@item @code{C-s} (@code{isearch-forward})
@kindex C-s, in Info windows
@findex isearch-forward
Interactively searches forward through the info file for a string as you
type it.

@item @code{C-r} (@code{isearch-backward})
@kindex C-r, in Info windows
@findex isearch-backward
Interactively searches backward through the info file for a string as
you type it.

@item @code{i} (@code{index-search})
@kindex i, in Info windows
@findex index-search
Looks up a string in the indices for this info file, and selects a node
where the found index entry points to.

@item @code{,} (@code{next-index-match})
@kindex , in Info windows
@findex next-index-match
Moves to the node containing the next matching index item from the last
@samp{i} command.
@end table

The most basic searching command is @samp{s} (@code{search}).  The
@samp{s} command prompts you for a string in the echo area, and then
searches the remainder of the info file for an occurrence of that string.
If the string is found, the node containing it is selected, and the
cursor is left positioned at the start of the found string.  Subsequent
@samp{s} commands show you the default search string within @samp{[} and
@samp{]}; pressing @key{RET} instead of typing a new string will use the
default search string.

@dfn{Incremental searching} is similar to basic searching, but the
string is looked up while you are typing it, instead of waiting until
the entire search string has been specified.

@node Xref Commands, Window Commands, Searching Commands, Using Info
@appendixsec Selecting Cross References

We have already discussed the @samp{Next}, @samp{Prev}, and @samp{Up}
pointers which appear at the top of a node.  In addition to these
pointers, a node may contain other pointers which refer you to a
different node, perhaps in another info file.  Such pointers are called
@dfn{cross references}, or @dfn{xrefs} for short.

@menu
* Parts of an Xref::            What a cross reference is made of.
* Selecting Xrefs::             Commands for selecting menu or note items.
@end menu

@node Parts of an Xref, Selecting Xrefs, Xref Commands, Xref Commands
@appendixsubsec Parts of an Xref

Cross references have two major parts: the first part is called the
@dfn{label}; it is the name that you can use to refer to the cross
reference, and the second is the @dfn{target}; it is the full name of
the node that the cross reference points to.

The target is separated from the label by a colon @samp{:}; first the
label appears, and then the target.  For example, in the sample menu
cross reference below, the single colon separates the label from the
target.

@example
* Foo Label: Foo Target.	More information about Foo.
@end example

Note the @samp{.} which ends the name of the target.  The @samp{.} is
not part of the target; it serves only to let Info know where the target
name ends.

A shorthand way of specifying references allows two adjacent colons to
stand for a target name which is the same as the label name:

@example
* Foo Commands::		Commands pertaining to Foo.
@end example

In the above example, the name of the target is the same as the name of
the label, in this case @code{Foo Commands}.

You will normally see two types of cross references while viewing nodes:
@dfn{menu} references, and @dfn{note} references.  Menu references
appear within a node's menu; they begin with a @samp{*} at the beginning
of a line, and continue with a label, a target, and a comment which
describes what the contents of the node pointed to contains.

Note references appear within the body of the node text; they begin with
@code{*Note}, and continue with a label and a target.

Like @samp{Next}, @samp{Prev} and @samp{Up} pointers, cross references
can point to any valid node.  They are used to refer you to a place
where more detailed information can be found on a particular subject.
Here is a cross reference which points to a node within the Texinfo
documentation:  @xref{xref, , Writing an Xref, texinfo, the Texinfo
Manual}, for more information on creating your own texinfo cross
references.

@node Selecting Xrefs,  , Parts of an Xref, Xref Commands
@appendixsubsec Selecting Xrefs

The following table lists the Info commands which operate on menu items.

@table @asis
@item @code{1} (@code{menu-digit})
@itemx @code{2} @dots{} @code{9}
@cindex 1 @dots{} 9, in Info windows
@kindex 1 @dots{} 9, in Info windows
@findex menu-digit
Within an Info window, pressing a single digit, (such as @samp{1}),
selects that menu item, and places its node in the current window.
For convenience, there is one exception; pressing @samp{0} selects the
@emph{last} item in the node's menu.

@item @code{0} (@code{last-menu-item})
@kindex 0, in Info windows
@findex last-menu-item
Select the last item in the current node's menu.

@item @code{m} (@code{menu-item})
@kindex m, in Info windows
@findex menu-item
Reads the name of a menu item in the echo area and selects its node.
Completion is available while reading the menu label.

@item @code{M-x find-menu}
@findex find-menu
Moves the cursor to the start of this node's menu.
@end table

This table lists the Info commands which operate on note cross references.

@table @asis
@item @code{f} (@code{xref-item})
@itemx @code{r}
@kindex f, in Info windows
@kindex r, in Info windows
@findex xref-item
Reads the name of a note cross reference in the echo area and selects
its node.  Completion is available while reading the cross reference
label.
@end table

Finally, the next few commands operate on menu or note references alike:

@table @asis
@item @code{TAB} (@code{move-to-next-xref})
@kindex TAB, in Info windows
@findex move-to-next-xref
Moves the cursor to the start of the next nearest menu item or note
reference in this node.  You can then use @key{RET}
(@code{select-reference-this-line} to select the menu or note reference.

@item @code{M-TAB} (@code{move-to-prev-xref})
@kindex M-TAB, in Info windows
@findex move-to-prev-xref
Moves the cursor the start of the nearest previous menu item or note
reference in this node.

@item @code{RET} (@code{select-reference-this-line})
@kindex RET, in Info windows
@findex select-reference-this-line
Selects the menu item or note reference appearing on this line.
@end table

@node Window Commands, Printing Nodes, Xref Commands, Using Info
@appendixsec Manipulating Multiple Windows
@cindex windows, manipulating

A @dfn{window} is a place to show the text of a node.  Windows have a
view area where the text of the node is displayed, and an associated
@dfn{mode line}, which briefly describes the node being viewed.

GNU Info supports multiple windows appearing in a single screen; each
window is separated from the next by its modeline.  At any time, there
is only one @dfn{active} window, that is, the window in which the cursor
appears.  There are commands available for creating windows, changing
the size of windows, selecting which window is active, and for deleting
windows.

@menu
* The Mode Line::               What appears in the mode line?
* Basic Windows::               Manipulating windows in Info.
* The Echo Area::               Used for displaying errors and reading input.
@end menu

@node The Mode Line, Basic Windows, Window Commands, Window Commands
@appendixsubsec The Mode Line

A @dfn{mode line} is a line of inverse video which appears at the bottom
of an info window.  It describes the contents of the window just above
it; this information includes the name of the file and node appearing in
that window, the number of screen lines it takes to display the node,
and the percentage of text that is above the top of the window.  It can
also tell you if the indirect tags table for this info file needs to be
updated, and whether or not the info file was compressed when stored on
disk.

Here is a sample mode line for a window containing an uncompressed file
named @file{dir}, showing the node @samp{Top}.

@smallexample
-----Info: (dir)Top, 40 lines --Top------------------------------------
            ^^   ^   ^^^        ^^
          (file)Node #lines    where
@end smallexample

When a node comes from a file which is compressed on disk, this is
indicated in the mode line with two small @samp{z}'s.  In addition, if
the info file containing the node has been split into subfiles, the name
of the subfile containing the node appears in the modeline as well:

@smallexample
--zz-Info: (emacs)Top, 291 lines --Top-- Subfile: emacs-1.Z------------
@end smallexample 

When Info makes a node internally, such that there is no corresponding
info file on disk, the name of the node is surrounded by asterisks
(@samp{*}).  The name itself tells you what the contents of the window
are; the sample mode line below shows an internally constructed node
showing possible completions:

@smallexample
-----Info: *Completions*, 7 lines --All--------------------------------
@end smallexample

@node Basic Windows, The Echo Area, The Mode Line, Window Commands
@appendixsubsec Window Commands

It can be convenient to view more than one node at a time.  To allow
this, Info can display more than one @dfn{window}.  Each window has its
own mode line (@pxref{The Mode Line}) and history of nodes viewed in that
window (@pxref{Node Commands, , @code{history-node}}).

@table @asis
@item @code{C-x o} (@code{next-window})
@cindex windows, selecting
@kindex C-x o, in Info windows
@findex next-window
Selects the next window on the screen.  Note that the echo area can only be
selected if it is already in use, and you have left it temporarily.
Normally, @samp{C-x o} simply moves the cursor into the next window on
the screen, or if you are already within the last window, into the first
window on the screen.  Given a numeric argument, @samp{C-x o} moves over
that many windows.  A negative argument causes @samp{C-x o} to select
the previous window on the screen.

@item @code{M-x prev-window}
@findex prev-window
Selects the previous window on the screen.  This is identical to
@samp{C-x o} with a negative argument.

@item @code{C-x 2} (@code{split-window})
@cindex windows, creating
@kindex C-x 2, in Info windows
@findex split-window
Splits the current window into two windows, both showing the same node.
Each window is one half the size of the original window, and the cursor
remains in the original window.  The variable @code{automatic-tiling}
can cause all of the windows on the screen to be resized for you
automatically, please @pxref{Info Variables, , automatic-tiling} for
more information.

@item @code{C-x 0} (@code{delete-window})
@cindex windows, deleting
@kindex C-x 0, in Info windows
@findex delete-window
Deletes the current window from the screen.  If you have made too many
windows and your screen appears cluttered, this is the way to get rid of
some of them.

@item @code{C-x 1} (@code{keep-one-window})
@kindex C-x 1, in Info windows
@findex keep-one-window
Deletes all of the windows excepting the current one.

@item @code{ESC C-v} (@code{scroll-other-window})
@kindex ESC C-v, in Info windows
@findex scroll-other-window
Scrolls the other window, in the same fashion that @samp{C-v} might
scroll the current window.  Given a negative argument, the "other"
window is scrolled backward.

@item @code{C-x ^} (@code{grow-window})
@kindex C-x ^, in Info windows
@findex grow-window
Grows (or shrinks) the current window.  Given a numeric argument, grows
the current window that many lines; with a negative numeric argument,
the window is shrunk instead.

@item @code{C-x t} (@code{tile-windows})
@cindex tiling
@kindex C-x t, in Info windows
@findex tile-windows
Divides the available screen space among all of the visible windows.
Each window is given an equal portion of the screen in which to display
its contents.  The variable @code{automatic-tiling} can cause
@code{tile-windows} to be called when a window is created or deleted.
@xref{Info Variables, , @code{automatic-tiling}}.
@end table

@node The Echo Area,  , Basic Windows, Window Commands
@appendixsubsec The Echo Area
@cindex echo area

The @dfn{echo area} is a one line window which appears at the bottom of
the screen.  It is used to display informative or error messages, and to
read lines of input from you when that is necessary.  Almost all of the
commands available in the echo area are identical to their Emacs
counterparts, so please refer to that documentation for greater depth of
discussion on the concepts of editing a line of text.  The following
table briefly lists the commands that are available while input is being
read in the echo area:

@table @asis
@item @code{C-f} (@code{echo-area-forward})
@kindex C-f, in the Info echo area
@findex echo-area-forward
Moves forward a character.

@item @code{C-b} (@code{echo-area-backward})
@kindex C-b, in the Info echo area
@findex echo-area-backward
Moves backward a character.

@item @code{C-a} (@code{echo-area-beg-of-line})
@kindex C-a, in the Info echo area
@findex echo-area-beg-of-line
Moves to the start of the input line.

@item @code{C-e} (@code{echo-area-end-of-line})
@kindex C-e, in the Info echo area
@findex echo-area-end-of-line
Moves to the end of the input line.

@item @code{M-f} (@code{echo-area-forward-word})
@kindex M-f, in the Info echo area
@findex echo-area-forward-word
Moves forward a word.

@item @code{M-b} (@code{echo-area-backward-word})
@kindex M-b, in the Info echo area
@findex echo-area-backward-word
Moves backward a word.

@item @code{C-d} (@code{echo-area-delete})
@kindex C-d, in the Info echo area
@findex echo-area-delete
Deletes the character under the cursor.

@item @code{DEL} (@code{echo-area-rubout})
@kindex DEL, in the Info echo area
@findex echo-area-rubout
Deletes the character behind the cursor.

@item @code{C-g} (@code{echo-area-abort})
@kindex C-g, in the Info echo area
@findex echo-area-abort
Cancels or quits the current operation.  If completion is being read,
@samp{C-g} discards the text of the input line which does not match any
completion.  If the input line is empty, @samp{C-g} aborts the calling
function.

@item @code{RET} (@code{echo-area-newline})
@kindex RET, in the Info echo area
@findex echo-area-newline
Accepts (or forces completion of) the current input line.

@item @code{C-q} (@code{echo-area-quoted-insert})
@kindex C-q, in the Info echo area
@findex echo-area-quoted-insert
Inserts the next character verbatim.  This is how you can insert control
characters into a search string, for example.

@item @var{printing character} (@code{echo-area-insert})
@kindex printing characters, in the Info echo area
@findex echo-area-insert
Inserts the character.

@item @code{M-TAB} (@code{echo-area-tab-insert})
@kindex M-TAB, in the Info echo area
@findex echo-area-tab-insert
Inserts a TAB character.

@item @code{C-t} (@code{echo-area-transpose-chars})
@kindex C-t, in the Info echo area
@findex echo-area-transpose-chars
Transposes the characters at the cursor.
@end table

The next group of commands deal with @dfn{killing}, and @dfn{yanking}
text.  For an in depth discussion of killing and yanking,
@pxref{Killing, , Killing and Deleting, emacs, the GNU Emacs Manual}

@table @asis
@item @code{M-d} (@code{echo-area-kill-word})
@kindex M-d, in the Info echo area
@findex echo-area-kill-word
Kills the word following the cursor.

@item @code{M-DEL} (@code{echo-area-backward-kill-word})
@kindex M-DEL, in the Info echo area
@findex echo-area-backward-kill-word
Kills the word preceding the cursor.

@item @code{C-k} (@code{echo-area-kill-line})
@kindex C-k, in the Info echo area
@findex echo-area-kill-line
Kills the text from the cursor to the end of the line.

@item @code{C-x DEL} (@code{echo-area-backward-kill-line})
@kindex C-x DEL, in the Info echo area
@findex echo-area-backward-kill-line
Kills the text from the cursor to the beginning of the line.

@item @code{C-y} (@code{echo-area-yank})
@kindex C-y, in the Info echo area
@findex echo-area-yank
Yanks back the contents of the last kill.

@item @code{M-y} (@code{echo-area-yank-pop})
@kindex M-y, in the Info echo area
@findex echo-area-yank-pop
Yanks back a previous kill, removing the last yanked text first.
@end table

Sometimes when reading input in the echo area, the command that needed
input will only accept one of a list of several choices.  The choices
represent the @dfn{possible completions}, and you must respond with one
of them.  Since there are a limited number of responses you can make,
Info allows you to abbreviate what you type, only typing as much of the
response as is necessary to uniquely identify it.  In addition, you can
request Info to fill in as much of the response as is possible; this
is called @dfn{completion}.

The following commands are available when completing in the echo area:

@table @asis
@item @code{TAB} (@code{echo-area-complete})
@itemx @code{SPC}
@kindex TAB, in the Info echo area
@kindex SPC, in the Info echo area
@findex echo-area-complete
Inserts as much of a completion as is possible.

@item @code{?} (@code{echo-area-possible-completions})
@kindex ?, in the Info echo area
@findex echo-area-possible-completions
Displays a window containing a list of the possible completions of what
you have typed so far.  For example, if the available choices are:
@example
bar
foliate
food
forget
@end example
and you have typed an @samp{f}, followed by @samp{?}, the possible
completions would contain:
@example
foliate
food
forget
@end example
i.e., all of the choices which begin with @samp{f}.  Pressing @key{SPC}
or @key{TAB} would result in @samp{fo} appearing in the echo area, since
all of the choices which begin with @samp{f} continue with @samp{o}.
Now, typing @samp{l} followed by @samp{TAB} results in @samp{foliate}
appearing in the echo area, since that is the only choice which begins
with @samp{fol}.

@item @code{ESC C-v} (@code{echo-area-scroll-completions-window})
@kindex ESC C-v, in the Info echo area
@findex echo-area-scroll-completions-window
Scrolls the completions window, if that is visible, or the "other"
window if not.
@end table

@node Printing Nodes, Other Info Commands, Window Commands, Using Info
@appendixsec Printing Out Nodes
@cindex printing

You may wish to print out the contents of a node as  a quick reference
document for later use.  Info provides you with a command for doing
this.  In general, we recommend that you use @TeX{} to format the
document and print sections of it, by running @code{tex} on the texinfo
source file.

@table @asis
@item @code{M-x print-node}
@findex print-node
@cindex INFO_PRINT_COMMAND, environment variable
Pipes the contents of the current node through the command in the
environment variable @code{INFO_PRINT_COMMAND}.  If the variable doesn't
exist, the node is simply piped to @code{lpr}.
@end table

@node Other Info Commands, Info Variables, Printing Nodes, Using Info
@appendixsec Miscellaneous Info Commands

GNU Info contains several commands which self-document GNU Info:

@table @asis
@item @code{M-x describe-command}
@cindex functions, describing
@cindex commands, describing
@findex describe-command
Reads the name of an Info command in the echo area and then displays a
brief description of what that command does.

@item @code{M-x describe-key}
@cindex keys, describing
@findex describe-key
Reads a key sequence in the echo area, and then displays the name and
documentation of the Info command that the key sequence invokes.

@item @code{M-x describe-variable}
Reads the name of a variable in the echo area and then displays a brief
description of what the variable affects.

@item @code{M-x where-is}
@findex where-is
Reads the name of an Info command in the echo area, and then displays
a key sequence which can be typed in order to invoke that command.

@item @code{C-h} (@code{get-help-window})
@itemx @code{?}
@kindex C-h, in Info windows
@kindex ?, in Info windows
@findex get-help-window
Creates (or moves into) the window displaying @code{*Help*}, and places
a node containing a quick reference card into it.  This window displays
the most concise information about GNU Info available.

@item @code{h} (@code{get-info-help-node})
@kindex h, in Info windows
@findex get-info-help-node
Tries hard to visit the node @code{(info)Help}.  The info file
@file{info.texi} distributed with GNU Info contains this node.  Of
course, the file must first be processed with @code{makeinfo}, and then
placed into the location of your info directory.
@end table

Here are the commands for creating a numeric argument:

@table @asis
@item @code{C-u} (@code{universal-argument})
@cindex numeric arguments
@kindex C-u, in Info windows
@findex universal-argument
Starts (or multiplies by 4) the current numeric argument.  @samp{C-u} is
a good way to give a small numeric argument to cursor movement or
scrolling commands; @samp{C-u C-v} scrolls the screen 4 lines, while
@samp{C-u C-u C-n} moves the cursor down 16 lines.

@item @code{M-1} (@code{add-digit-to-numeric-arg})
@itemx @code{M-2} @dots{} @code{M-9}
@kindex M-1 @dots{} M-9, in Info windows
@findex add-digit-to-numeric-arg
Adds the digit value of the invoking key to the current numeric
argument.  Once Info is reading a numeric argument, you may just type
the digits of the argument, without the Meta prefix.  For example, you
might give @samp{C-l} a numeric argument of 32 by typing:

@example
@kbd{C-u 3 2 C-l}
@end example
or
@example
@kbd{M-3 2 C-l}
@end example
@end table

@samp{C-g} is used to abort the reading of a multi-character key
sequence, to cancel lengthy operations (such as multi-file searches) and
to cancel reading input in the echo area.

@table @asis
@item @code{C-g} (@code{abort-key})
@cindex cancelling typeahead
@cindex cancelling the current operation
@kindex C-g, in Info windows
@findex abort-key
Cancels current operation.
@end table

The @samp{q} command of Info simply quits running Info.

@table @asis
@item @code{q} (@code{quit})
@cindex quitting
@kindex q, in Info windows
@findex quit
Exits GNU Info.
@end table

If the operating system tells GNU Info that the screen is 60 lines tall,
and it is actually only 40 lines tall, here is a way to tell Info that
the operating system is correct.

@table @asis
@item @code{M-x set-screen-height}
@findex set-screen-height
@cindex screen, changing the height of
Reads a height value in the echo area and sets the height of the
displayed screen to that value.
@end table

Finally, Info provides a convenient way to display footnotes which might
be associated with the current node that you are viewing:

@table @asis
@item @code{ESC C-f} (@code{show-footnotes})
@kindex ESC C-f, in Info windows
@findex show-footnotes
@cindex footnotes, displaying
Shows the footnotes (if any) associated with the current node in another
window.  You can have Info automatically display the footnotes
associated with a node when the node is selected by setting the variable
@code{automatic-footnotes}.
@xref{Info Variables, , @code{automatic-footnotes}}.
@end table

@node Info Variables,  , Other Info Commands, Using Info
@appendixsec Manipulating Variables

GNU Info contains several @dfn{variables} whose values are looked at by various
Info commands.  You can change the values of these variables, and thus
change the behavior of Info to more closely match your environment and
info file reading manner.

@table @asis
@item @code{M-x set-variable}
@cindex variables, setting
@findex set-variable
Reads the name of a variable, and the value for it, in the echo area and
then sets the variable to that value.  Completion is available when
reading the variable name; often, completion is available when reading
the value to give to the variable, but that depends on the variable
itself.  If a variable does @emph{not} supply multiple choices to
complete over, it expects a numeric value.

@item @code{M-x describe-variable}
@cindex variables, describing
@findex describe-variable
Reads the name of a variable in the echo area and then displays a brief
description of what the variable affects.
@end table

Here is a list of the variables that you can set in Info.

@table @code
@item automatic-footnotes
@vindex automatic-footnotes
When set to @code{On}, footnotes appear and disappear automatically.
This variable is @code{On} by default.  When a node is selected, a
window containing the footnotes which appear in that node is created,
and the footnotes are displayed within the new window.  The window that
Info creates to contain the footnotes is called @samp{*Footnotes*}.  If
a node is selected which contains no footnotes, and a @samp{*Footnotes*}
window is on the screen, the @samp{*Footnotes*} window is deleted.
Footnote windows created in this fashion are not automatically tiled so
that they can use as little of the display as is possible.

@item automatic-tiling
@vindex automatic-tiling
When set to @code{On}, creating or deleting a window resizes other
windows.  This variable is @code{Off} by default.  Normally, typing
@samp{C-x 2} divides the current window into two equal parts.  When
@code{automatic-tiling} is set to @code{On}, all of the windows are
resized automatically, keeping an equal number of lines visible in each
window.  There are exceptions to the automatic tiling; specifically, the
windows @samp{*Completions*} and @samp{*Footnotes*} are @emph{not}
resized through automatic tiling; they remain their original size.

@item visible-bell
@vindex visible-bell
When set to @code{On}, GNU Info attempts to flash the screen instead of
ringing the bell.  This variable is @code{Off} by default.  Of course,
Info can only flash the screen if the terminal allows it; in the case
that the terminal does not allow it, the setting of this variable has no
effect.  However, you can make Info perform quietly by setting the
@code{errors-ring-bell} variable to @code{Off}.

@item errors-ring-bell
@vindex errors-ring-bell
When set to @code{On}, errors cause the bell to ring.  The default
setting of this variable is @code{On}.

@item gc-compressed-files
@vindex gc-compressed-files
When set to @code{On}, Info garbage collects files which had to be
uncompressed.  The default value of this variable is @code{Off}.
Whenever a node is visited in Info, the info file containing that node
is read into core, and Info reads information about the tags and nodes
contained in that file.  Once the tags information is read by Info, it
is never forgotten.  However, the actual text of the nodes does not need
to remain in core unless a particular info window needs it.  For
non-compressed files, the text of the nodes does not remain in core when
it is no longer in use.  But de-compressing a file can be a time
consuming operation, and so Info tries hard not to do it twice.
@code{gc-compressed-files} tells Info it is okay to garbage collect the
text of the nodes of a file which was compressed on disk.

@item show-index-match
@vindex show-index-match
When set to @code{On}, the portion of the matched search string is
highlighted in the message which explains where the matched search
string was found.  The default value of this variable is @code{On}.
When Info displays the location where an index match was found,
(@pxref{Searching Commands, , @code{next-index-match}}), the portion of the
string that you had typed is highlighted by displaying it in the inverse
case from its surrounding characters.

@item scroll-behaviour
@vindex scroll-behaviour
Controls what happens when forward scrolling is requested at the end of
a node, or when backward scrolling is requested at the beginning of a
node.  The default value for this variable is @code{Continuous}.  There
are three possible values for this variable:

@table @code
@item Continuous
Tries to get the first item in this node's menu, or failing that, the
@samp{Next} node, or failing that, the @samp{Next} of the @samp{Up}.
This behavior is identical to using the @samp{]}
(@code{global-next-node}) and @samp{[} (@code{global-prev-node})
commands.

@item Next Only
Only tries to get the @samp{Next} node.

@item Page Only
Simply gives up, changing nothing.  If @code{scroll-behaviour} is
@code{Page Only}, no scrolling command can change the node that is being
viewed.
@end table

@item scroll-step
@vindex scroll-step
The number of lines to scroll when the cursor moves out of the window.
Scrolling happens automatically if the cursor has moved out of the
visible portion of the node text when it is time to display.  Usually
the scrolling is done so as to put the cursor on the center line of the
current window.  However, if the variable @code{scroll-step} has a
nonzero value, Info attempts to scroll the node text by that many lines;
if that is enough to bring the cursor back into the window, that is what
is done.  The default value of this variable is 0, thus placing the
cursor (and the text it is attached to) in the center of the window.
Setting this variable to 1 causes a kind of "smooth scrolling" which
some people prefer.

@item ISO-Latin
@cindex ISO Latin characters
@vindex ISO-Latin
When set to @code{On}, Info accepts and displays ISO Latin characters.
By default, Info assumes an ASCII character set.  @code{ISO-Latin} tells
Info that it is running in an environment where the European standard
character set is in use, and allows you to input such characters to
Info, as well as display them.
@end table