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[bpt/emacs.git] / man / info.texi
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26901792 1\input texinfo @c -*-texinfo-*-
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2@comment %**start of header
3@setfilename info.info
4@settitle Info
5@syncodeindex fn cp
6@syncodeindex vr cp
7@syncodeindex ky cp
8@comment %**end of header
b08bd2df 9@comment $Id: info.texi,v 1.16 2001/09/19 20:21:02 rms Exp $
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10
11@dircategory Texinfo documentation system
26901792 12@direntry
b457dbd9 13* Info: (info). Documentation browsing system.
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14@end direntry
15
26901792 16@ifinfo
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17This file describes how to use Info, the on-line, menu-driven GNU
18documentation system.
26901792 19
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20Copyright (C) 1989, 92, 96, 97, 98, 99, 2000, 2001
21Free Software Foundation, Inc.
26901792 22
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23
24Permission is granted to copy, distribute and/or modify this document
25under the terms of the GNU Free Documentation License, Version 1.1 or
26any later version published by the Free Software Foundation; with no
27Invariant Sections, with the Front-Cover texts being ``A GNU
28Manual'', and with the Back-Cover Texts as in (a) below. A copy of the
29license is included in the section entitled ``GNU Free Documentation
30License'' in the Emacs manual.
31
32(a) The FSF's Back-Cover Text is: ``You have freedom to copy and modify
33this GNU Manual, like GNU software. Copies published by the Free
34Software Foundation raise funds for GNU development.''
35
36This document is part of a collection distributed under the GNU Free
37Documentation License. If you want to distribute this document
38separately from the collection, you can do so by adding a copy of the
39license to the document, as described in section 6 of the license.
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40@end ifinfo
41
26901792 42@titlepage
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43@title Info
44@subtitle The online, hyper-text GNU documentation system
45@author Brian Fox
46@author and the GNU Texinfo community
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47@page
48@vskip 0pt plus 1filll
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49Copyright @copyright{} 1989, 92, 93, 96, 97, 98, 99, 2000, 2001
50Free Software Foundation, Inc.
26901792 51@sp 2
26901792 52Published by the Free Software Foundation @*
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5359 Temple Place - Suite 330 @*
54Boston, MA 02111-1307, USA.
26901792 55
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56Permission is granted to copy, distribute and/or modify this document
57under the terms of the GNU Free Documentation License, Version 1.1 or
58any later version published by the Free Software Foundation; with no
59Invariant Sections, with the Front-Cover texts being ``A GNU
60Manual'', and with the Back-Cover Texts as in (a) below. A copy of the
61license is included in the section entitled ``GNU Free Documentation
62License'' in the Emacs manual.
63
64(a) The FSF's Back-Cover Text is: ``You have freedom to copy and modify
65this GNU Manual, like GNU software. Copies published by the Free
66Software Foundation raise funds for GNU development.''
67
68This document is part of a collection distributed under the GNU Free
69Documentation License. If you want to distribute this document
70separately from the collection, you can do so by adding a copy of the
71license to the document, as described in section 6 of the license.
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72@end titlepage
73
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74@ifnottex
75@node Top
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76@top Info: An Introduction
77
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78Info is a program, which you are using now, for reading documentation of
79computer programs. The GNU Project distributes most of its on-line
80manuals in the Info format, so you need a program called @dfn{Info
81reader} to read the manuals. One of such programs you are using now.
26901792 82
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83@ifinfo
84If you are new to Info and want to learn how to use it, type the
85command @kbd{h} now. It brings you to a programmed instruction
86sequence.
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87
88To learn advanced Info commands, type @kbd{n} twice. This brings you to
89@cite{Info for Experts}, skipping over the `Getting Started' chapter.
90@end ifinfo
b457dbd9 91@end ifnottex
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92
93@menu
94* Getting Started:: Getting started using an Info reader.
95* Advanced Info:: Advanced commands within Info.
b457dbd9 96* Creating an Info File:: How to make your own Info file.
768e4b74 97* Index:: An index of topics, commands, and variables.
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98@end menu
99
100@node Getting Started, Advanced Info, Top, Top
101@comment node-name, next, previous, up
102@chapter Getting Started
103
104This first part of the Info manual describes how to get around inside
105of Info. The second part of the manual describes various advanced
106Info commands, and how to write an Info as distinct from a Texinfo
b457dbd9 107file. The third part briefly explains how to generate Info files from
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108Texinfo files.
109
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110@ifnotinfo
111This manual is primarily designed for browsing with an Info reader
112program on a computer, so that you can try Info commands while reading
113about them. Reading it on paper or with an HTML browser is less
26901792 114effective, since you must take it on faith that the commands described
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115really do what the manual says. By all means go through this manual
116now that you have it; but please try going through the on-line version
117as well.
26901792 118
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119@cindex Info reader, how to invoke
120@cindex entering Info
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121There are two ways of looking at the online version of this manual:
122
123@enumerate
124@item
125Type @code{info} at your shell's command line. This approach uses a
3c7625c9 126stand-alone program designed just to read Info files.
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127
128@item
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129Type @code{emacs} at the command line; then type @kbd{C-h i}
130(@kbd{Control-h}, followed by @kbd{i}). This approach uses the Info
131mode of the Emacs program, an editor with many other capabilities.
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132@end enumerate
133
134In either case, then type @kbd{mInfo} (just the letters), followed by
135@key{RET}---the ``Return'' or ``Enter'' key. At this point, you should
136be ready to follow the instructions in this manual as you read them on
137the screen.
138@c FIXME! (pesch@cygnus.com, 14 dec 1992)
139@c Is it worth worrying about what-if the beginner goes to somebody
140@c else's Emacs session, which already has an Info running in the middle
141@c of something---in which case these simple instructions won't work?
b457dbd9 142@end ifnotinfo
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143
144@menu
145* Help-Small-Screen:: Starting Info on a Small Screen
146* Help:: How to use Info
147* Help-P:: Returning to the Previous node
e4a9d9e3 148* Help-^L:: The Space, DEL, B and ^L commands.
26901792 149* Help-M:: Menus
e4a9d9e3 150* Help-Xref:: Following cross-references
2fc7d480 151* Help-Int:: Some intermediate Info commands
26901792 152* Help-Q:: Quitting Info
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153@end menu
154
b457dbd9 155@node Help-Small-Screen
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156@section Starting Info on a Small Screen
157
b457dbd9 158@ifnotinfo
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159(In Info, you only see this section if your terminal has a small
160number of lines; most readers pass by it without seeing it.)
b457dbd9 161@end ifnotinfo
26901792 162
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163@cindex small screen, moving around
164Since your terminal has a relatively small number of lines on its
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165screen, it is necessary to give you special advice at the beginning.
166
b457dbd9 167If you see the text @samp{--All----} near the bottom right corner
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168of the screen, it means the entire text you are looking at fits on the
169screen. If you see @samp{--Top----} instead, it means that there is
170more text below that does not fit. To move forward through the text
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171and see another screen full, press @key{SPC}, the Space bar. To move
172back up, press the key labeled @samp{Backspace} or @samp{DEL} (on some
173keyboards, this key might be labeled @samp{Delete}).
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174
175@ifinfo
3c7625c9 176Here are 40 lines of junk, so you can try @key{SPC} and @key{DEL} and
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177see what they do. At the end are instructions of what you should do
178next.
b457dbd9 179
26901792 180@format
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181This is line 20
182This is line 21
183This is line 22
184This is line 23
185This is line 24
186This is line 25
187This is line 26
188This is line 27
189This is line 28
190This is line 29
191This is line 30
192This is line 31
193This is line 32
194This is line 33
195This is line 34
196This is line 35
197This is line 36
198This is line 37
199This is line 38
200This is line 39
201This is line 40
202This is line 41
203This is line 42
204This is line 43
205This is line 44
206This is line 45
207This is line 46
208This is line 47
209This is line 48
210This is line 49
211This is line 50
212This is line 51
213This is line 52
214This is line 53
215This is line 54
216This is line 55
217This is line 56
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218This is line 57
219This is line 58
220This is line 59
26901792 221@end format
b457dbd9 222
26901792 223If you have managed to get here, go back to the beginning with
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224@kbd{DEL} (or @key{BACKSPACE}), and come back here again, then you
225understand the about the @samp{Space} and @samp{Backspace} keys. So
226now type an @kbd{n} ---just one character; don't type the quotes and
227don't type the Return key afterward--- to get to the normal start of
228the course.
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229@end ifinfo
230
231@node Help, Help-P, Help-Small-Screen, Getting Started
232@comment node-name, next, previous, up
233@section How to use Info
234
235You are talking to the program Info, for reading documentation.
236
b457dbd9 237@cindex node, in Info documents
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238 Right now you are looking at one @dfn{Node} of Information.
239A node contains text describing a specific topic at a specific
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240level of detail. This node's topic is ``how to use Info''. The mode
241line says that this is node @samp{Help} in the file @file{info}.
26901792 242
b457dbd9 243@cindex header of Info node
26901792 244 The top line of a node is its @dfn{header}. This node's header (look at
b457dbd9 245it now) says that the @samp{Next} node after this one is the node
26901792 246called @samp{Help-P}. An advanced Info command lets you go to any node
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247whose name you know. In the stand-alone Info reader program, the
248header line shows the names of this node and the info file as well.
249In Emacs, the header line is displayed in a special typeface, and it
250doesn't scroll off the screen when you scroll the display. The names
251of this node and of its Info file are omitted by Emacs from the header
252line.
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253
254 Besides a @samp{Next}, a node can have a @samp{Previous} or an
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255@samp{Up} links, or both. As you can see, this node has all of these
256links.
26901792 257
b457dbd9 258@kindex n @r{(Info mode)}
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259 Now it is time to move on to the @samp{Next} node, named @samp{Help-P}.
260
261@format
b457dbd9 262>> Type @kbd{n} to move there. Type just one character;
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263 do not type the quotes and do not type a @key{RET} afterward.
264@end format
265
b457dbd9 266@noindent
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267@samp{>>} in the margin means it is really time to try a command.
268
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269@format
270>> If you have a mouse, and if you already practiced typing @kbd{n}
271 to get to the next node, click now with the right mouse button on
272 the @samp{Next} link to do the same ``the mouse way''.
273@end format
274
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275@node Help-P, Help-^L, Help, Getting Started
276@comment node-name, next, previous, up
277@section Returning to the Previous node
278
b457dbd9 279@kindex p @r{(Info mode)}
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280This node is called @samp{Help-P}. The @samp{Previous} node, as you see,
281is @samp{Help}, which is the one you just came from using the @kbd{n}
282command. Another @kbd{n} command now would take you to the next
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283node, @samp{Help-^L}. In Emacs, @kbd{n} runs the Emacs command
284@code{Info-next}, and @kbd{p} runs @code{Info-prev}.
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285
286@format
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287>> But do not type @kbd{n} yet. First, try the @kbd{p} command,
288 or click the mouse on the @samp{Prev} link, which takes you to the
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289 @samp{Previous} node. When you get there, you can do an @kbd{n}
290 again to return here.
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291@end format
292
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293 If you read this in Emacs, you will see an @samp{Info} item in the
294menu bar, close to its right edge. Clicking your mouse on the
295@samp{Info} menu-bar item opens a menu of commands which include
296@samp{Next} and @samp{Prev} (and also some others which you didn't yet
297learn about).
298
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299 This all probably seems insultingly simple so far, but @emph{do not} be
300led into skimming. Things will get more complicated soon. Also,
301do not try a new command until you are told it is time to. Otherwise,
302you may make Info skip past an important warning that was coming up.
303
304@format
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305>> Now do an @kbd{n}, or click the mouse on the @samp{Next} link, to
306 get to the node @samp{Help-^L} and learn more.
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307@end format
308
309@node Help-^L, Help-M, Help-P, Getting Started
310@comment node-name, next, previous, up
b457dbd9 311@section The Space, DEL, B and ^L commands.
26901792 312
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313 This node's mode line tells you that you are now at node @samp{Help-^L},
314and the header line tells you that @kbd{p} would get you back to
315@samp{Help-P}. The node's title is underlined; it says what the node
316is about (most nodes have titles).
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317
318 This is a big node and it does not all fit on your display screen.
319You can tell that there is more that is not visible because you
320can see the string @samp{--Top-----} rather than @samp{--All----} near
321the bottom right corner of the screen.
322
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323@kindex SPC @r{(Info mode)}
324@kindex DEL @r{(Info mode)}
325@kindex BACKSPACE @r{(Info mode)}
326@findex Info-scroll-up
327@findex Info-scroll-down
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328 The @key{SPC}, @key{BACKSPACE} (or @key{DEL})@footnote{The key which
329we call ``Backspace or DEL'' in this manual is labeled differently on
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330different keyboards. Look for a key which is a little ways above the
331@key{ENTER} or @key{RET} key and which you normally use outside Emacs
332to erase the character before the cursor, i.e.@: the character you
333typed last. It might be labeled @samp{Backspace} or @samp{<-} or
334@samp{DEL}, or sometimes @samp{Delete}.} and @kbd{b} commands exist to
335allow you to ``move around'' in a node that does not all fit on the
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336screen at once. @key{SPC} moves forward, to show what was below the
337bottom of the screen. @key{DEL} or @key{BACKSPACE} moves backward, to
338show what was above the top of the screen (there is not anything above
339the top until you have typed some spaces). In Emacs, @key{SPC} runs
340the command @code{Info-scroll-up}, while @key{BACKSPACE} runs
341@code{Info-scroll-down}.
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342
343@format
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344>> Now try typing a @key{SPC} (afterward, type a @key{BACKSPACE} to
345 return here).
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346@end format
347
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348 When you type the @key{SPC}, the two lines that were at the bottom of
349the screen appear at the top, followed by more lines. @key{DEL} or
350@key{BACKSPACE} takes the two lines from the top and moves them to the
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351bottom, @emph{usually}, but if there are not a full screen's worth of
352lines above them they may not make it all the way to the bottom.
353
354 If you are reading this in Emacs, note that the header line is
355always visible, never scrolling off the display. That way, you can
356always see the @samp{Next}, @samp{Prev}, and @samp{Up} links, and you
357can conveniently go to one of these links from anywhere in the node by
358clicking the mouse on one of these links.
359
360@cindex reading Info documents top to bottom
361@cindex Info documents as tutorials
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362 @key{SPC} and @key{DEL} not only move forward and backward through
363the current node. When these keys hit the beginning or the end of the
364current node, they move to preceding or subsequent nodes.
365Specifically, they scroll through all the nodes in an Info file as a
366single logical sequence. In this sequence, a node's subnodes appear
367following their parent. If a node has a menu, @key{SPC} takes you
368into the subnodes listed in the menu, one by one. Once you reach the
369end of a node, and have seen all of its subnodes, @key{SPC} takes you
370to the next node or to the parent's next node. This is so you could
371read the entire manual top to bottom by just typing @key{SPC}.
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372
373@kindex PAGEUP @r{(Info mode)}
374@kindex PAGEDOWN @r{(Info mode)}
375 Many keyboards nowadays have two scroll keys labeled @samp{PageUp}
376and @samp{PageDown} (or maybe @samp{Prior} and @samp{Next}). If your
377keyboard has these keys, you can use them to move forward and backward
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378through the text, like with @key{SPC} and @key{BACKSPACE}. However,
379unlike @key{SPC} and @key{BACKSPACE}, @key{PAGEUP} and @key{PAGEDOWN}
380keys will never scroll beyond the beginning or the end of the current
381node.
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382
383@kindex C-l @r{(Info mode)}
1fdd9f43 384 If your screen is ever garbaged, you can tell Info to display it
b457dbd9 385again by typing @kbd{C-l} (@kbd{Control-L}, that is---hold down
3c7625c9 386@key{CTRL} and type @kbd{L} or @kbd{l}).
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387
388@format
389>> Type @kbd{C-l} now.
390@end format
391
b457dbd9 392@kindex b @r{(Info mode)}
26901792 393 To move back to the beginning of the node you are on, you can type
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394a lot of @key{BACKSPACE} keys. You can also type simply @kbd{b} for
395beginning.
b457dbd9 396
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397@format
398>> Try that now. (We have put in enough verbiage to push this past
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399 the first screenful, but screens are so big nowadays that perhaps it
400 isn't enough. You may need to shrink your Emacs or Info window.)
b08bd2df 401 Then come back, with @key{SPS}s.
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402@end format
403
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404 If your screen is very tall, all of this node might fit at once.
405In that case, @kbd{b} won't do anything. Sorry; what can we do?
26901792 406
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407@kindex ? @r{(Info mode)}
408@findex Info-summary
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409 You have just learned a considerable number of commands. If you
410want to use one but have trouble remembering which, you should type
79c43dcd 411a @kbd{?} (in Emacs it runs the @code{Info-summary} command) which
1fdd9f43 412displays a brief list of commands. When you are finished looking at
3c7625c9 413the list, make it go away by typing a @key{SPC} repeatedly.
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414
415@format
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416>> Type a @key{?} now. Press @key{SPC} to see consecutive screenfuls of
417 the list until finished. Then type @key{SPC} several times, until
418 it goes away.
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419@end format
420
b457dbd9 421 (If you are using the stand-alone Info reader, type @kbd{C-x 0} to
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422return here, that is---press and hold @key{CTRL}, type an @kbd{x},
423then release @key{CTRL} and @kbd{x}, and press @kbd{0}---a zero, not
b457dbd9 424the letter ``o''.)
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425
426 From now on, you will encounter large nodes without warning, and
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427will be expected to know how to use @key{SPC} and @key{BACKSPACE} to
428move around in them without being told. Since not all terminals have
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429the same size screen, it would be impossible to warn you anyway.
430
431@format
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432>> Now type @kbd{n}, or click the mouse on the @samp{Next} link, to
433 see the description of the @kbd{m} command.
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434@end format
435
e4a9d9e3 436@node Help-M, Help-Xref, Help-^L, Getting Started
26901792 437@comment node-name, next, previous, up
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438@section Menus and the @kbd{m} command
439
440@cindex menus in an Info document
441@cindex Info menus
442 With only the @kbd{n} (next) and @kbd{p} (previous) commands for
443moving between nodes, nodes are restricted to a linear sequence.
444Menus allow a branching structure. A menu is a list of other nodes
445you can move to. It is actually just part of the text of the node
446formatted specially so that Info can interpret it. The beginning of a
447menu is always identified by a line which starts with @samp{* Menu:}.
448A node contains a menu if and only if it has a line in it which starts
449that way. The only menu you can use at any moment is the one in the
450node you are in. To use a menu in any other node, you must move to
451that node first.
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452
453 After the start of the menu, each line that starts with a @samp{*}
454identifies one subtopic. The line usually contains a brief name
455for the subtopic (followed by a @samp{:}), the name of the node that talks
456about that subtopic, and optionally some further description of the
457subtopic. Lines in the menu that do not start with a @samp{*} have no
458special meaning---they are only for the human reader's benefit and do
459not define additional subtopics. Here is an example:
460
461@example
b457dbd9 462* Foo: Node about FOO This tells about FOO
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463@end example
464
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465The subtopic name is Foo, and the node describing it is @samp{Node
466about FOO}. The rest of the line is just for the reader's
467Information. [[ But this line is not a real menu item, simply because
468there is no line above it which starts with @samp{* Menu:}.]]
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469
470 When you use a menu to go to another node (in a way that will be
471described soon), what you specify is the subtopic name, the first
472thing in the menu line. Info uses it to find the menu line, extracts
473the node name from it, and goes to that node. The reason that there
474is both a subtopic name and a node name is that the node name must be
475meaningful to the computer and may therefore have to be ugly looking.
476The subtopic name can be chosen just to be convenient for the user to
477specify. Often the node name is convenient for the user to specify
478and so both it and the subtopic name are the same. There is an
479abbreviation for this:
480
481@example
482* Foo:: This tells about FOO
483@end example
484
485@noindent
486This means that the subtopic name and node name are the same; they are
487both @samp{Foo}.
488
489@format
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490>> Now use @key{SPC} to find the menu in this node, then come back to
491 the front with a @kbd{b} and some @key{SPC}s. As you see, a menu is
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492 actually visible in its node. If you cannot find a menu in a node
493 by looking at it, then the node does not have a menu and the
494 @kbd{m} command is not available.
495@end format
496
b457dbd9 497@kindex m @r{(Info mode)}
26901792 498 The command to go to one of the subnodes is @kbd{m}---but @emph{do
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499not do it yet!} Before you use @kbd{m}, you need to learn about
500commands which prompt you for more input. So far, you have learned
501several commands that do not need additional input; when you typed
502one, Info processed it and was instantly ready for another command.
503The @kbd{m} command is different: it is incomplete without the
504@dfn{name of the subtopic}. Once you have typed @kbd{m}, Info tries
505to read the subtopic name.
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506
507 Now look for the line containing many dashes near the bottom of the
508screen. There is one more line beneath that one, but usually it is
509blank. If it is empty, Info is ready for a command, such as @kbd{n}
3c7625c9 510or @kbd{b} or @key{SPC} or @kbd{m}. If that line contains text ending
b457dbd9 511in a colon, it means Info is trying to read more input for the last
26901792 512command. At such times, commands do not work, because Info tries to
b457dbd9 513use them as the input it needs. You must either type your response and
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514finish the command you started, or type @kbd{Control-g} to cancel the
515command. When you have done one of those things, the line becomes
516blank again.
517
b457dbd9 518@findex Info-menu
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519 The command to go to a subnode via a menu is @kbd{m}. After you type
520the @kbd{m}, the line at the bottom of the screen says @samp{Menu item: }.
521You must then type the name of the subtopic you want, and end it with
b457dbd9 522a @key{RET}. In Emacs, @kbd{m} runs the command @code{Info-menu}.
26901792 523
b457dbd9 524@cindex abbreviating Info subnodes
26901792 525 You can abbreviate the subtopic name. If the abbreviation is not
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526unique, the first matching subtopic is chosen. Some menus put
527the shortest possible abbreviation for each subtopic name in capital
528letters, so you can see how much you need to type. It does not
529matter whether you use upper case or lower case when you type the
530subtopic. You should not put any spaces at the end, or inside of the
531item name, except for one space where a space appears in the item in
532the menu.
533
534@cindex completion of Info node names
26901792 535 You can also use the @dfn{completion} feature to help enter the subtopic
3c7625c9 536name. If you type the @key{TAB} key after entering part of a name, it will
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537magically fill in more of the name---as much as follows uniquely from
538what you have entered.
539
540 If you move the cursor to one of the menu subtopic lines, then you do
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541not need to type the argument: you just type a @key{RET}, and it
542stands for the subtopic of the line you are on.
26901792 543
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544Here is a menu to give you a chance to practice. This menu gives you
545three ways of going to one place, Help-FOO:
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546
547@menu
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548* Foo: Help-FOO. A node you can visit for fun.
549* Bar: Help-FOO. Strange! two ways to get to the same place.
550* Help-FOO:: And yet another!
551@end menu
552
553@format
554>> Now type just an @kbd{m} and see what happens:
555@end format
556
557 Now you are ``inside'' an @kbd{m} command. Commands cannot be used
558now; the next thing you will type must be the name of a subtopic.
559
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560 You can change your mind about doing the @kbd{m} by typing
561@kbd{Control-g}.
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562
563@format
564>> Try that now; notice the bottom line clear.
b457dbd9 565@end format
26901792 566
b457dbd9 567@format
26901792 568>> Then type another @kbd{m}.
b457dbd9 569@end format
26901792 570
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571@format
572>> Now type @kbd{BAR}, the item name. Do not type @key{RET} yet.
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573@end format
574
b457dbd9 575 While you are typing the item name, you can use the @key{DEL} (or
3c7625c9 576@key{BACKSPACE}) key to cancel one character at a time if you make a
b457dbd9 577mistake.
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578
579@format
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580>> Press @key{DEL} to cancel the @samp{R}. You could type another @kbd{R}
581 to replace it. But you do not have to, since @samp{BA} is a valid
582 abbreviation.
583@end format
26901792 584
b457dbd9 585@format
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586>> Now you are ready to go. Type a @key{RET}.
587@end format
588
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589 After visiting @samp{Help-FOO}, you should return here.
590
591 Another way to move to the menu subtopic lines and between them is
592to type @key{TAB}. Each time you type a @key{TAB}, you move to the
593next subtopic line. To move to a previous subtopic line, type
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594@kbd{M-@key{TAB}}---that is, press and hold the @key{META} key and then
595press @key{TAB}. (On some keyboards, the @key{META} key might be labeled
596@samp{Alt}.)
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597
598 Once you move cursor to a subtopic line, press @key{RET} to go to
599that subtopic's node.
600
601@cindex mouse support in Info mode
602@kindex Mouse-2 @r{(Info mode)}
603 If your terminal supports a mouse, you have yet another way of going
604to a subtopic. Move your mouse pointer to the subtopic line,
605somewhere between the beginning @samp{*} and the colon @samp{:} which
606ends the subtopic's brief name. You will see the subtopic's name
607change its appearance (usually, its background color will change), and
608the shape of the mouse pointer will change if your platform supports
609that. After a while, if you leave the mouse on that spot, a tooltip
610will pop up saying ``Mouse-2: go to that node''. (If the tooltips are
1fdd9f43 611turned off or unavailable, this message is displayed in the @dfn{echo
3c7625c9 612area}, the bottom screen line where you typed the menu subtopics in
b457dbd9 613response to the prompt.) @kbd{Mouse-2} is the second button of your
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614mouse counting from the left---the rightmost button for two-button
615mice, the middle button for 3-button mice. So pressing @kbd{Mouse-2}
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616while the mouse pointer is on a menu subtopic goes to that subtopic.
617
618@findex Info-mouse-follow-nearest-node
619 More generally, @kbd{Mouse-2} in an Info buffer runs the Emacs
620command @code{Info-mouse-follow-nearest-node}, which finds the nearest
621link to another node and goes there. For example, near a cross
622reference it acts like @kbd{f}, in a menu it acts like @kbd{m}, on the
623node's header line it acts like @kbd{n}, @kbd{p}, or @kbd{u}, etc. At
624end of the node's text @kbd{Mouse-2} moves to the next node, or up if
625there's no next node.
626
627 Here is another way to get to Help-FOO, a menu. You can ignore this
628if you want, or else try it by typing @key{TAB} and then @key{RET}, or
629clicking @kbd{Mouse-2} on it (but then please come back to here).
630
631@menu
632* Help-FOO::
633@end menu
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634
635@format
636>> Type @kbd{n} to see more commands.
637@end format
638
26901792 639@node Help-FOO, , , Help-M
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640@subsection The @kbd{u} command
641
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642 Congratulations! This is the node @samp{Help-FOO}. It has an @samp{Up}
643pointer @samp{Help-M}, the node you just came from via the @kbd{m}
644command. This is the usual convention---the nodes you reach from a menu
645have @samp{Up} nodes that lead back to the menu. Menus move Down in the
646tree, and @samp{Up} moves Up. @samp{Previous}, on the other hand, is
647usually used to ``stay on the same level but go backwards''.
26901792 648
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649@kindex u @r{(Info mode)}
650@findex Info-up
26901792 651 You can go back to the node @samp{Help-M} by typing the command
3c7625c9 652@kbd{u} for ``Up'' (the Emacs command run by @kbd{u} is
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653@code{Info-up}). That puts you at the @emph{front} of the node---to
654get back to where you were reading you have to type some @key{SPC}s.
655(Some Info readers, such as the one built into Emacs, put you at the
656same place where you were reading in @samp{Help-M}.)
657
658 Another way to go Up is to click on the @samp{Up} pointer shown in
659the header line (provided that you have a mouse).
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660
661@format
662>> Now type @kbd{u} to move back up to @samp{Help-M}.
663@end format
664
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665@node Help-Xref, Help-Int, Help-M, Getting Started
666@comment node-name, next, previous, up
667@section Following Cross-References
668
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669@cindex cross references in Info documents
670 In Info documentation, you will see many @dfn{cross references}.
671Cross references look like this: @xref{Help-Cross, Cross}. That text
672is a real, live cross reference, whose name is @samp{Cross} and which
673points to the node named @samp{Help-Cross}.
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674
675@kindex f @r{(Info mode)}
676@findex Info-follow-reference
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677 There are two ways to follow a cross reference. You can move the
678cursor to it and press @key{RET}, just as in a menu. @key{RET}
679follows the cross reference that the cursor is on. Or you can type
680@kbd{f} and then specify the name of the cross reference (in this
681case, @samp{Cross}) as an argument. In Emacs Info, @kbd{f} runs
682@code{Info-follow-reference},
683
684 In the @kbd{f} command, you select the cross reference with its
685name, so it does not matter where the cursor was. If the cursor is on
686or near a cross reference, @kbd{f} suggests that reference name in
687parentheses as the default; typing @key{RET} will follow that
688reference. However, if you type a different reference name, @kbd{f}
689will follow the other reference which has that name.
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690
691@format
1fdd9f43 692>> Type @kbd{f}, followed by @kbd{Cross}, and then @key{RET}.
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693@end format
694
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695 As you enter the reference name, you can use the @key{DEL} (or
696@key{BACKSPACE}) key to edit your input. If you change your mind
697about following any reference, you can use @kbd{Control-g} to cancel
698the command. Completion is available in the @kbd{f} command; you can
699complete among all the cross reference names in the current node by
700typing a @key{TAB}.
701
702 To get a list of all the cross references in the current node, you
703can type @kbd{?} after an @kbd{f}. The @kbd{f} continues to await a
704cross reference name even after displaying the list, so if you don't
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705actually want to follow a reference, you should type a @kbd{Control-g}
706to cancel the @kbd{f}.
707
708@format
709>> Type @kbd{f?} to get a list of the cross references in this node. Then
710 type a @kbd{Control-g} and see how the @samp{f} gives up.
711@end format
712
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713 The @key{TAB} and @kbd{M-@key{TAB}} key, which move between menu
714items in a menu, also move between cross references outside of menus.
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715
716@node Help-Int, Help-Q, Help-Xref, Getting Started
26901792 717@comment node-name, next, previous, up
2fc7d480 718@section Some intermediate Info commands
26901792 719
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720 The introductory course is almost over; please continue
721a little longer to learn some intermediate-level commands.
26901792 722
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723 Most Info files have an index, which is actually a large node that
724contains nothing but a menu. The menu has one menu item for each
725topic listed in the index. You can find the index node from the main
726menu of the file, with the @kbd{m} command; then you can use the
727@kbd{m} command again in the index node to go to the node that
728describes the topic.
729
730 There is also a short-cut Info command, @kbd{i}, which does all of
731that for you. It searches the index for a given topic (a string) and
732goes to the node which is listed in the index for that topic.
733@xref{Info Search}, for a full explanation.
734
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735@kindex l @r{(Info mode)}
736@findex Info-last
737@cindex going back in Info mode
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738 If you have been moving around to different nodes and wish to
739retrace your steps, the @kbd{l} command (@kbd{l} for @dfn{last}) will
740do that, one node-step at a time. As you move from node to node, Info
741records the nodes where you have been in a special history list. The
742@kbd{l} command revisits nodes in the history list; each successive
743@kbd{l} command moves one step back through the history.
744
b457dbd9 745 If you have been following directions, ad @kbd{l} command now will get
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746you back to @samp{Help-M}. Another @kbd{l} command would undo the
747@kbd{u} and get you back to @samp{Help-FOO}. Another @kbd{l} would undo
748the @kbd{m} and get you back to @samp{Help-M}.
749
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750 In Emacs, @kbd{l} runs the command @code{Info-last}.
751
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752@format
753>> Try typing three @kbd{l}'s, pausing in between to see what each
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754 @kbd{l} does. Then follow directions again and you will end up
755 back here.
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756@end format
757
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758 Note the difference between @kbd{l} and @kbd{p}: @kbd{l} moves to
759where @emph{you} last were, whereas @kbd{p} always moves to the node
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760which the header says is the @samp{Previous} node (from this node, the
761@samp{Prev} link leads to @samp{Help-M}).
762
763@kindex d @r{(Info mode)}
764@findex Info-directory
765@cindex go to Directory node
766 The @kbd{d} command (@code{Info-directory} in Emacs) gets you
767instantly to the Directory node. This node, which is the first one
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768you saw when you entered Info, has a menu which leads (directly or
769indirectly, through other menus), to all the nodes that exist. The
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770Directory node lists all the manuals and other Info documents that
771are, or could be, installed on your system.
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772
773@format
b457dbd9 774>> Try doing a @kbd{d}, then do an @kbd{l} to return here (yes,
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775 @emph{do} return).
776@end format
777
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778@kindex t @r{(Info mode)}
779@findex Info-top-node
780@cindex go to Top node
781 The @kbd{t} command moves to the @samp{Top} node of the manual.
782This is useful if you want to browse the manual's main menu, or select
783some specific top-level menu item. The Emacs command run by @kbd{t}
784is @code{Info-top-node}.
785
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786 Clicking @kbd{Mouse-2} on or near a cross reference also follows the
787reference. You can see that the cross reference is mouse-sensitive by
788moving the mouse pointer to the reference and watching how the
789underlying text and the mouse pointer change in response.
790
791@format
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792>> Now type @kbd{n} to see the last node of the course.
793@end format
794
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795 @xref{Advanced Info}, for more advanced Info features.
796
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797@c If a menu appears at the end of this node, remove it.
798@c It is an accident of the menu updating command.
799
b457dbd9 800@node Advanced Info
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801@chapter Info for Experts
802
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803 This chapter describes various advanced Info commands. (If you are
804using a stand-alone Info reader, there are additional commands
805specific to it, which are documented in several chapters of @ref{Top,,
806GNU Info, info-stnd, GNU Info}.)
807
808 This chapter also explains how to write an Info as distinct from a
809Texinfo file. (However, in most cases, writing a Texinfo file is
810better, since you can use it @emph{both} to generate an Info file and
811to make a printed manual. @xref{Top,, Overview of Texinfo, texinfo,
812Texinfo: The GNU Documentation Format}.)
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813
814@menu
815* Expert:: Advanced Info commands: g, s, e, and 1 - 5.
b457dbd9 816* Info Search:: How to search Info documents for specific subjects.
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817* Add:: Describes how to add new nodes to the hierarchy.
818 Also tells what nodes look like.
819* Menus:: How to add to or create menus in Info nodes.
820* Cross-refs:: How to add cross-references to Info nodes.
821* Tags:: How to make tags tables for Info files.
822* Checking:: Checking an Info File
823* Emacs Info Variables:: Variables modifying the behavior of Emacs Info.
824@end menu
825
b457dbd9 826@node Expert, Info Search, , Advanced Info
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827@comment node-name, next, previous, up
828@section Advanced Info Commands
829
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830Here are some more Info commands that make it easier to move around.
831
832@unnumberedsubsec @kbd{g} goes to a node by name
26901792 833
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834@kindex g @r{(Info mode)}
835@findex Info-goto-node
836@cindex go to a node by name
837 If you know a node's name, you can go there by typing @kbd{g}, the
26901792 838name, and @key{RET}. Thus, @kbd{gTop@key{RET}} would go to the node
b457dbd9 839called @samp{Top} in this file. (This is equivalent to @kbd{t}, see
2fc7d480 840@ref{Help-Int}.) @kbd{gExpert@key{RET}} would come back here.
b457dbd9 841@kbd{g} in Emacs runs the command @code{Info-goto-node}.
26901792 842
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843 Unlike @kbd{m}, @kbd{g} does not allow the use of abbreviations.
844But it does allow completion, so you can type @key{TAB} to complete a
845partial node name.
26901792 846
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847@cindex go to another Info file
848 To go to a node in another file, you can include the file name in the
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849node name by putting it at the front, in parentheses. Thus,
850@kbd{g(dir)Top@key{RET}} would go to the Info Directory node, which is
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851the node @samp{Top} in the Info file @file{dir}. Likewise,
852@kbd{g(emacs)Top@key{RET}} goes to the top node of the Emacs manual.
26901792 853
b457dbd9 854 The node name @samp{*} specifies the whole file. So you can look at
26901792 855all of the current file by typing @kbd{g*@key{RET}} or all of any
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856other file with @kbd{g(@var{filename})@key{RET}}.
857
858@unnumberedsubsec @kbd{1} -- @kbd{9} choose a menu subtopic by its number
859
860@kindex 1 @r{through} 9 @r{(Info mode)}
861@findex Info-nth-menu-item
862@cindex select @var{n}'th menu item
863 If you begrudge each character of type-in which your system requires,
864you might like to use the commands @kbd{1}, @kbd{2}, @kbd{3}, @kbd{4},
865@dots{}, @kbd{9}. They are short for the @kbd{m} command together
866with a name of a menu subtopic. @kbd{1} goes through the first item
867in the current node's menu; @kbd{2} goes through the second item, etc.
868In the stand-alone reader, @kbd{0} goes through the last menu item;
869this is so you need not count how many entries are there. In Emacs,
870the digit keys run the command @code{Info-nth-menu-item}.
871
872 If your display supports multiple fonts, and you are using Emacs'
873Info mode to read Info files, the @samp{*} for the fifth menu item
874stands out, either in color or in some other attribute, such as
875underline, and so is the @samp{*} for the ninth item; this makes it
876easy to see at a glance which number to use for an item.
877
878 Some terminals don't support colors or underlining. If you need to
26901792 879actually count items, it is better to use @kbd{m} instead, and specify
b457dbd9 880the name, or use @key{TAB} to quickly move between menu items.
26901792 881
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882@unnumberedsubsec @kbd{e} makes Info document editable
883
884@kindex e @r{(Info mode)}
885@findex Info-edit
886@cindex edit Info document
887 The Info command @kbd{e} changes from Info mode to an ordinary
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888Emacs editing mode, so that you can edit the text of the current node.
889Type @kbd{C-c C-c} to switch back to Info. The @kbd{e} command is allowed
890only if the variable @code{Info-enable-edit} is non-@code{nil}.
891
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892 The @kbd{e} command only works in Emacs, where it runs the command
893@code{Info-edit}. The stand-alone Info reader doesn't allow you to
894edit the Info file, so typing @kbd{e} there goes to the end of the
895current node.
896
897@node Info Search, Add, Expert, Advanced Info
898@comment node-name, next, previous, up
899@section How to search Info documents for specific subjects
900
901@cindex searching Info documents
902@cindex Info document as a reference
903 The commands which move between and inside nodes allow you to read
904the entire manual or its large portions. But what if you need to find
905some information in the manual as fast as you can, and you don't know
906or don't remember in what node to look for it? This need arises when
907you use a manual as a @dfn{reference}, or when it is impractical to
908read the entire manual before you start using the programs it
909describes.
910
911 Info has powerful searching facilities that let you find things
912quickly. You can search either the manual indices or its text.
913
914@kindex i @r{(Info mode)}
915@findex Info-index
916 Since most subjects related to what the manual describes should be
917indexed, you should try the index search first. The @kbd{i} command
918prompts you for a subject and then looks up that subject in the
919indices. If it finds an index entry with the subject you typed, it
920goes to the node to which that index entry points. You should browse
921through that node to see whether the issue you are looking for is
922described there. If it isn't, type @kbd{,} one or more times to go
923through additional index entries which match your subject.
924
925 The @kbd{i} command finds all index entries which include the string
926you typed @emph{as a substring}. For each match, Info shows in the
927echo area the full index entry it found. Often, the text of the full
928index entry already gives you enough information to decide whether it
929is relevant to what you are looking for, so we recommend that you read
930what Emacs shows in the echo are before looking at the node it
931displays.
932
933 Since @kbd{i} looks for a substring, you can search for subjects even
934if you are not sure how they are spelled in the index. For example,
935suppose you want to find something that is pertinent to commands which
936complete partial input (e.g., when you type @key{TAB}). If you want
937to catch index entries that refer to ``complete'', ``completion'', and
938``completing'', you could type @kbd{icomplet@key{RET}}.
939
940 Info documents which describe programs should index the commands,
941options, and key sequences that the program provides. If you are
942looking for a description of a command, an option, or a key, just type
943their names when @kbd{i} prompts you for a topic. For example, if you
944want to read the description of what the @kbd{C-f} key does, type
945@kbd{iC-f@key{RET}}. Here @kbd{C-f} are 3 literal characters
946@samp{C}, @samp{-}, and @samp{f}, not the ``Control-f'' command key
947you type inside Emacs to run the command bound to @kbd{C-f}.
948
949 In Emacs, @kbd{i} runs the command @code{Info-index}.
950
951@kindex s @r{(Info mode)}
952@findex Info-search
953 The @kbd{s} command allows you to search a whole file for a string.
954It switches to the next node if and when that is necessary. You
955type @kbd{s} followed by the string to search for, terminated by
956@key{RET}. To search for the same string again, just @kbd{s} followed
957by @key{RET} will do. The file's nodes are scanned in the order
958they are in in the file, which has no necessary relationship to the
959order that they may be in the tree structure of menus and @samp{next}
960pointers. But normally the two orders are not very different. In any
961case, you can always do a @kbd{b} to find out what node you have
962reached, if the header is not visible (this can happen, because @kbd{s}
963puts your cursor at the occurrence of the string, not at the beginning
964of the node).
965
966@kindex M-s @r{(Info mode)}
967 In Emacs, @kbd{Meta-s} is equivalent to @kbd{s}. That is for
968compatibility with other GNU packages that use @kbd{M-s} for a similar
969kind of search command. Both @kbd{s} and @kbd{M-s} run in Emacs the
970command @code{Info-search}.
971
972
973@node Add, Menus, Info Search, Advanced Info
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974@comment node-name, next, previous, up
975@section Adding a new node to Info
976
977To add a new topic to the list in the Info directory, you must:
b457dbd9 978
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979@enumerate
980@item
981Create some nodes, in some file, to document that topic.
982@item
983Put that topic in the menu in the directory. @xref{Menus, Menu}.
984@end enumerate
985
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986 Usually, the way to create the nodes is with Texinfo (@pxref{Top,,
987Overview of Texinfo, texinfo, Texinfo: The GNU Documentation Format});
988this has the advantage that you can also make a printed manual from
989them. However, if you want to edit an Info file, here is how.
26901792 990
b457dbd9 991@cindex node delimiters
26901792 992 The new node can live in an existing documentation file, or in a new
79c43dcd 993one. It must have a @samp{^_} character before it (invisible to the
26901792 994user; this node has one but you cannot see it), and it ends with either
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995a @samp{^_}, a @samp{^L} (``formfeed''), or the end of file.@footnote{If
996you put in a @samp{^L} to end a new node, be sure that there is a
997@samp{^_} after it to start the next one, since @samp{^L} cannot
998@emph{start} a node. Also, a nicer way to make a node boundary be a
999page boundary as well is to put a @samp{^L} @emph{right after} the
1000@samp{^_}.}
1001
1002 The @samp{^_} starting a node must be followed by a newline or a
1003@samp{^L} newline, after which comes the node's header line. The header
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1004line must give the node's name (by which Info finds it), and state the
1005names of the @samp{Next}, @samp{Previous}, and @samp{Up} nodes (if there
1006are any). As you can see, this node's @samp{Up} node is the node
1007@samp{Top}, which points at all the documentation for Info. The
1008@samp{Next} node is @samp{Menus}.
1009
1010@cindex node header line format
1011@cindex format of node headers
1012 The keywords @dfn{Node}, @dfn{Next}, @dfn{Previous}, and @dfn{Up}
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1013may appear in any order, anywhere in the header line, but the
1014recommended order is the one in this sentence. Each keyword must be
1015followed by a colon, spaces and tabs, and then the appropriate name.
1016The name may be terminated with a tab, a comma, or a newline. A space
1017does not end it; node names may contain spaces. The case of letters
1018in the names is insignificant.
1019
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1020@cindex node name format
1021@cindex Directory node
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1022 A node name has two forms. A node in the current file is named by
1023what appears after the @samp{Node: } in that node's first line. For
1024example, this node's name is @samp{Add}. A node in another file is
1025named by @samp{(@var{filename})@var{node-within-file}}, as in
1026@samp{(info)Add} for this node. If the file name starts with ``./'',
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1027then it is relative to the current directory; otherwise, it is
1028relative starting from the standard directory for Info files of your
1029site. The name @samp{(@var{filename})Top} can be abbreviated to just
1030@samp{(@var{filename})}. By convention, the name @samp{Top} is used
1031for the ``highest'' node in any single file---the node whose @samp{Up}
1032points out of the file. The @samp{Directory} node is @file{(dir)}, it
1033points to a file @file{dir} which holds a large menu listing all the
1034Info documents installed on your site. The @samp{Top} node of a
1035document file listed in the @samp{Directory} should have an @samp{Up:
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1036(dir)} in it.
1037
b457dbd9 1038@cindex unstructured documents
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1039 The node name @kbd{*} is special: it refers to the entire file.
1040Thus, @kbd{g*} shows you the whole current file. The use of the
1041node @kbd{*} is to make it possible to make old-fashioned,
1042unstructured files into nodes of the tree.
1043
1044 The @samp{Node:} name, in which a node states its own name, must not
b457dbd9
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1045contain a file name, since when Info searches for a node, it does not
1046expect a file name to be there. The @samp{Next}, @samp{Previous} and
1047@samp{Up} names may contain them. In this node, since the @samp{Up}
1048node is in the same file, it was not necessary to use one.
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1049
1050 Note that the nodes in this file have a file name in the header
1051line. The file names are ignored by Info, but they serve as comments
1052to help identify the node for the user.
1053
1054@node Menus, Cross-refs, Add, Advanced Info
1055@comment node-name, next, previous, up
1056@section How to Create Menus
1057
b457dbd9 1058 Any node in the Info hierarchy may have a @dfn{menu}---a list of subnodes.
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1059The @kbd{m} command searches the current node's menu for the topic which it
1060reads from the terminal.
1061
b457dbd9 1062@cindex menu and menu entry format
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1063 A menu begins with a line starting with @samp{* Menu:}. The rest of the
1064line is a comment. After the starting line, every line that begins
b457dbd9
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1065with a @samp{* } lists a single topic. The name of the topic--what
1066the user must type at the @kbd{m}'s command prompt to select this
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1067topic---comes right after the star and space, and is followed by a
1068colon, spaces and tabs, and the name of the node which discusses that
1069topic. The node name, like node names following @samp{Next}, @samp{Previous}
1070and @samp{Up}, may be terminated with a tab, comma, or newline; it may also
1071be terminated with a period.
1072
1073 If the node name and topic name are the same, then rather than
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1074giving the name twice, the abbreviation @samp{* @var{name}::} may be
1075used (and should be used, whenever possible, as it reduces the visual
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1076clutter in the menu).
1077
1078 It is considerate to choose the topic names so that they differ
1079from each other very near the beginning---this allows the user to type
1080short abbreviations. In a long menu, it is a good idea to capitalize
1081the beginning of each item name which is the minimum acceptable
1082abbreviation for it (a long menu is more than 5 or so entries).
1083
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1084 The nodes listed in a node's menu are called its ``subnodes'', and it
1085is their ``superior''. They should each have an @samp{Up:} pointing at
1086the superior. It is often useful to arrange all or most of the subnodes
1087in a sequence of @samp{Next} and @samp{Previous} pointers so that
1088someone who wants to see them all need not keep revisiting the Menu.
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1089
1090 The Info Directory is simply the menu of the node @samp{(dir)Top}---that
1091is, node @samp{Top} in file @file{.../info/dir}. You can put new entries
1092in that menu just like any other menu. The Info Directory is @emph{not} the
1093same as the file directory called @file{info}. It happens that many of
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1094Info's files live in that file directory, but they do not have to; and
1095files in that directory are not automatically listed in the Info
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1096Directory node.
1097
1098 Also, although the Info node graph is claimed to be a ``hierarchy'',
1099in fact it can be @emph{any} directed graph. Shared structures and
1100pointer cycles are perfectly possible, and can be used if they are
1101appropriate to the meaning to be expressed. There is no need for all
1102the nodes in a file to form a connected structure. In fact, this file
1103has two connected components. You are in one of them, which is under
1104the node @samp{Top}; the other contains the node @samp{Help} which the
1105@kbd{h} command goes to. In fact, since there is no garbage
1106collector, nothing terrible happens if a substructure is not pointed
1107to, but such a substructure is rather useless since nobody can
1108ever find out that it exists.
1109
1110@node Cross-refs, Tags, Menus, Advanced Info
1111@comment node-name, next, previous, up
1112@section Creating Cross References
1113
b457dbd9 1114@cindex cross reference format
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1115 A cross reference can be placed anywhere in the text, unlike a menu
1116item which must go at the front of a line. A cross reference looks
b457dbd9 1117like a menu item except that it has @samp{*note} instead of @samp{*}.
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1118It @emph{cannot} be terminated by a @samp{)}, because @samp{)}'s are
1119so often part of node names. If you wish to enclose a cross reference
1120in parentheses, terminate it with a period first. Here are two
1121examples of cross references pointers:
1122
1123@example
1124*Note details: commands. (See *note 3: Full Proof.)
1125@end example
1126
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1127@noindent
1128@emph{These are just examples.} The places they ``lead to'' do not
1129really exist!
26901792 1130
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1131@menu
1132* Help-Cross:: Target of a cross-reference.
1133@end menu
1134
1135
1136@node Help-Cross, , , Cross-refs
1137@subsection The node reached by the cross reference in Info
1138
1139 This is the node reached by the cross reference named @samp{Cross}.
1140
1141 While this node is specifically intended to be reached by a cross
1142reference, most cross references lead to nodes that ``belong''
1143someplace else far away in the structure of an Info document. So you
1144cannot expect this node to have a @samp{Next}, @samp{Previous} or
1145@samp{Up} links pointing back to where you came from. In general, the
1146@kbd{l} (el) command is the only way to get back there.
1147
1148@format
1149>> Type @kbd{l} to return to the node where the cross reference was.
1150@end format
1151
2fc7d480 1152@node Help-Q, , Help-Int, Getting Started
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1153@comment node-name, next, previous, up
1154@section Quitting Info
1155
1156@kindex q @r{(Info mode)}
1157@findex Info-exit
1158@cindex quitting Info mode
1159 To get out of Info, back to what you were doing before, type @kbd{q}
1160for @dfn{Quit}. This runs @code{Info-exit} in Emacs.
1161
1162 This is the end of the basic course on using Info. You have learned
1163how to move in an Info document, and how to follow menus and cross
1164references. This makes you ready for reading manuals top to bottom,
1165as new users should do when they learn a new package.
1166
1167 Another set of Info commands is useful when you need to find
1168something quickly in a manual---that is, when you need to use a manual
1169as a reference rather than as a tutorial. We urge you to make learn
1170these search commands as well. If you want to do that now, follow this
1171cross reference to @ref{Info Search}.
1172
1173Yet another set of commands are meant for experienced users; you can
1174find them by looking in the Directory node for documentation on Info.
1175Finding them will be a good exercise in using Info in the usual
1176manner.
1177
1178@format
1179>> Type @kbd{d} to go to the Info directory node; then type
1180 @kbd{mInfo} and Return, to get to the node about Info and
1181 see what other help is available.
1182@end format
1183
1184
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1185@node Tags, Checking, Cross-refs, Advanced Info
1186@comment node-name, next, previous, up
1187@section Tags Tables for Info Files
1188
b457dbd9 1189@cindex tags tables in info files
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1190 You can speed up the access to nodes of a large Info file by giving
1191it a tags table. Unlike the tags table for a program, the tags table for
b457dbd9 1192an Info file lives inside the file itself and is used
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1193automatically whenever Info reads in the file.
1194
b457dbd9 1195@findex Info-tagify
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1196 To make a tags table, go to a node in the file using Emacs Info mode and type
1197@kbd{M-x Info-tagify}. Then you must use @kbd{C-x C-s} to save the
b457dbd9
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1198file. Info files produced by the @code{makeinfo} command that is part
1199of the Texinfo package always have tags tables to begin with.
26901792 1200
b457dbd9
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1201@cindex stale tags tables
1202@cindex update Info tags table
26901792 1203 Once the Info file has a tags table, you must make certain it is up
b457dbd9
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1204to date. If you edit an Info file directly (as opposed to editing its
1205Texinfo source), and, as a result of deletion of text, any node moves back
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1206more than a thousand characters in the file from the position
1207recorded in the tags table, Info will no longer be able to find that
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1208node. To update the tags table, use the @code{Info-tagify} command
1209again.
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1210
1211 An Info file tags table appears at the end of the file and looks like
1212this:
1213
1214@example
b457dbd9 1215^_^L
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1216Tag Table:
1217File: info, Node: Cross-refs^?21419
1218File: info, Node: Tags^?22145
1219^_
1220End Tag Table
1221@end example
1222
1223@noindent
1224Note that it contains one line per node, and this line contains
1225the beginning of the node's header (ending just after the node name),
79c43dcd 1226a @samp{DEL} character, and the character position in the file of the
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1227beginning of the node.
1228
b457dbd9 1229
26901792 1230@node Checking, Emacs Info Variables, Tags, Advanced Info
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1231@section Checking an Info File
1232
b457dbd9
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1233When creating an Info file, it is easy to forget the name of a node when
1234you are making a pointer to it from another node. If you put in the
1235wrong name for a node, this is not detected until someone tries to go
1236through the pointer using Info. Verification of the Info file is an
1237automatic process which checks all pointers to nodes and reports any
1238pointers which are invalid. Every @samp{Next}, @samp{Previous}, and
26901792 1239@samp{Up} is checked, as is every menu item and every cross reference. In
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1240addition, any @samp{Next} which does not have a @samp{Previous} pointing
1241back is reported. Only pointers within the file are checked, because
1242checking pointers to other files would be terribly slow. But those are
1243usually few.
26901792 1244
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1245@findex Info-validate
1246To check an Info file, do @kbd{M-x Info-validate} while looking at any
1247node of the file with Emacs Info mode.
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1248
1249@node Emacs Info Variables, , Checking, Advanced Info
1250@section Emacs Info-mode Variables
1251
b457dbd9 1252The following variables may modify the behavior of Info-mode in Emacs;
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1253you may wish to set one or several of these variables interactively, or
1254in your @file{~/.emacs} init file. @xref{Examining, Examining and Setting
1255Variables, Examining and Setting Variables, emacs, The GNU Emacs
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1256Manual}. The stand-alone Info reader program has its own set of
1257variables, described in @ref{Variables,, Manipulating Variables,
1258info-stnd, GNU Info}.
26901792 1259
b457dbd9 1260@vtable @code
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1261@item Info-directory-list
1262The list of directories to search for Info files. Each element is a
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GM
1263string (directory name) or @code{nil} (try default directory). If not
1264initialized Info uses the environment variable @env{INFOPATH} to
1265initialize it, or @code{Info-default-directory-list} if there is no
1266@env{INFOPATH} variable in the environment.
1267
1268@item Info-additional-directory-list
1269A list of additional directories to search for Info documentation files.
1270These directories are not searched for merging the @file{dir} file.
26901792 1271
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1272@item Info-fontify
1273When set to a non-@code{nil} value, enables highlighting of Info
1274files. The default is @code{t}. You can change how the highlighting
1275looks by customizing the faces @code{info-node}, @code{info-menu-5},
1276@code{info-xref}, @code{info-header-xref}, @code{info-header-node},
1277@code{info-title-@var{n}-face} (where @var{n} is the level of the
1278section, a number between 1 and 4), and @code{info-menu-header}. To
1279customize a face, type @kbd{M-x customize-face @key{RET} @var{face}
1280@key{RET}}, where @var{face} is one of the face names listed here.
1281
1282@item Info-use-header-line
1283If non-@code{nil}, Emacs puts in the Info buffer a header line showing
1284the @samp{Next}, @samp{Prev}, and @samp{Up} links. A header line does
1285not scroll with the rest of the buffer, making these links always
1286visible.
1287
1288@item Info-scroll-prefer-subnodes
3c7625c9
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1289If set to a non-@code{nil} value, @key{SPC} and @key{BACKSPACE} (or
1290@key{DEL}) keys in a menu visit subnodes of the current node before
1291scrolling to its end or beginning, respectively. For example, if the
1292node's menu appears on the screen, the next @key{SPC} moves to a
1293subnode indicated by the following menu item. Setting this option to
1294@code{nil} results in behavior similar to the stand-alone Info reader
1295program, which visits the first subnode from the menu only when you
1296hit the end of the current node. The default is @code{t}.
79148ea7 1297
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1298@item Info-enable-active-nodes
1299When set to a non-@code{nil} value, allows Info to execute Lisp code
1300associated with nodes. The Lisp code is executed when the node is
1301selected. The Lisp code to be executed should follow the node
79c43dcd 1302delimiter (the @samp{DEL} character) and an @samp{execute: } tag, like
3c7625c9 1303this:
26901792 1304
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1305@example
1306^_execute: (message "This is an active node!")
1307@end example
1308
1309@item Info-enable-edit
1310Set to @code{nil}, disables the @samp{e} (@code{Info-edit}) command. A
1311non-@code{nil} value enables it. @xref{Add, Edit}.
1312@end vtable
1313
1314
1315@node Creating an Info File
1316@chapter Creating an Info File from a Texinfo File
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1317
1318@code{makeinfo} is a utility that converts a Texinfo file into an Info
1319file; @code{texinfo-format-region} and @code{texinfo-format-buffer} are
1320GNU Emacs functions that do the same.
1321
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1322@xref{Top,, Overview of Texinfo, texinfo, Texinfo: The GNU
1323Documentation Format}, to learn how to write a Texinfo file.
1324
1325@xref{Creating an Info File,,, texinfo, Texinfo: The GNU Documentation
1326Format}, to learn how to create an Info file from a Texinfo file.
1327
1328@xref{Installing an Info File,,, texinfo, Texinfo: The GNU
1329Documentation Format}, to learn how to install an Info file after you
1330have created one.
1331
1332@node Index
1333@unnumbered Index
1334
1335This is an alphabetical listing of all the commands, variables, and
1336topics discussed in this document.
26901792 1337
b457dbd9 1338@printindex cp
26901792 1339
26901792 1340@bye