(tags-compression-info-list): Fix docstring
[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
768e4b74 9@comment $Id: info.texi,v 1.20 2001/05/03 14:02:33 karl 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.
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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
78Info is a program for reading documentation, which you are using now.
79
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80@ifinfo
81If you are new to Info and want to learn how to use it, type the
82command @kbd{h} now. It brings you to a programmed instruction
83sequence.
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84
85To learn advanced Info commands, type @kbd{n} twice. This brings you to
86@cite{Info for Experts}, skipping over the `Getting Started' chapter.
87@end ifinfo
b457dbd9 88@end ifnottex
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89
90@menu
91* Getting Started:: Getting started using an Info reader.
92* Advanced Info:: Advanced commands within Info.
b457dbd9 93* Creating an Info File:: How to make your own Info file.
768e4b74 94* Index:: An index of topics, commands, and variables.
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95@end menu
96
97@node Getting Started, Advanced Info, Top, Top
98@comment node-name, next, previous, up
99@chapter Getting Started
100
101This first part of the Info manual describes how to get around inside
102of Info. The second part of the manual describes various advanced
103Info commands, and how to write an Info as distinct from a Texinfo
b457dbd9 104file. The third part briefly explains how to generate Info files from
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105Texinfo files.
106
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107@ifnotinfo
108This manual is primarily designed for browsing with an Info reader
109program on a computer, so that you can try Info commands while reading
110about them. Reading it on paper or with an HTML browser is less
26901792 111effective, since you must take it on faith that the commands described
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112really do what the manual says. By all means go through this manual
113now that you have it; but please try going through the on-line version
114as well.
26901792 115
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116@cindex Info reader, how to invoke
117@cindex entering Info
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118There are two ways of looking at the online version of this manual:
119
120@enumerate
121@item
122Type @code{info} at your shell's command line. This approach uses a
3c7625c9 123stand-alone program designed just to read Info files.
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124
125@item
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126Type @code{emacs} at the command line; then type @kbd{C-h i}
127(@kbd{Control-h}, followed by @kbd{i}). This approach uses the Info
128mode of the Emacs program, an editor with many other capabilities.
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129@end enumerate
130
131In either case, then type @kbd{mInfo} (just the letters), followed by
132@key{RET}---the ``Return'' or ``Enter'' key. At this point, you should
133be ready to follow the instructions in this manual as you read them on
134the screen.
135@c FIXME! (pesch@cygnus.com, 14 dec 1992)
136@c Is it worth worrying about what-if the beginner goes to somebody
137@c else's Emacs session, which already has an Info running in the middle
138@c of something---in which case these simple instructions won't work?
b457dbd9 139@end ifnotinfo
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140
141@menu
142* Help-Small-Screen:: Starting Info on a Small Screen
143* Help:: How to use Info
144* Help-P:: Returning to the Previous node
145* Help-^L:: The Space, Rubout, B and ^L commands.
146* Help-M:: Menus
147* Help-Adv:: Some advanced Info commands
148* Help-Q:: Quitting Info
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149@end menu
150
b457dbd9 151@node Help-Small-Screen
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152@section Starting Info on a Small Screen
153
b457dbd9 154@ifnotinfo
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155(In Info, you only see this section if your terminal has a small
156number of lines; most readers pass by it without seeing it.)
b457dbd9 157@end ifnotinfo
26901792 158
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159@cindex small screen, moving around
160Since your terminal has a relatively small number of lines on its
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161screen, it is necessary to give you special advice at the beginning.
162
b457dbd9 163If you see the text @samp{--All----} near the bottom right corner
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164of the screen, it means the entire text you are looking at fits on the
165screen. If you see @samp{--Top----} instead, it means that there is
166more text below that does not fit. To move forward through the text
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167and see another screen full, press @key{SPC}, the Space bar. To move
168back up, press the key labeled @samp{Backspace} or @samp{DEL} (on some
169keyboards, this key might be labeled @samp{Delete}).
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170
171@ifinfo
3c7625c9 172Here are 40 lines of junk, so you can try @key{SPC} and @key{DEL} and
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173see what they do. At the end are instructions of what you should do
174next.
b457dbd9 175
26901792 176@format
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177This is line 20
178This is line 21
179This is line 22
180This is line 23
181This is line 24
182This is line 25
183This is line 26
184This is line 27
185This is line 28
186This is line 29
187This is line 30
188This is line 31
189This is line 32
190This is line 33
191This is line 34
192This is line 35
193This is line 36
194This is line 37
195This is line 38
196This is line 39
197This is line 40
198This is line 41
199This is line 42
200This is line 43
201This is line 44
202This is line 45
203This is line 46
204This is line 47
205This is line 48
206This is line 49
207This is line 50
208This is line 51
209This is line 52
210This is line 53
211This is line 54
212This is line 55
213This is line 56
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214This is line 57
215This is line 58
216This is line 59
26901792 217@end format
b457dbd9 218
26901792 219If you have managed to get here, go back to the beginning with
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220@kbd{DEL} (or @key{BACKSPACE}), and come back here again, then you
221understand the about the @samp{Space} and @samp{Backspace} keys. So
222now type an @kbd{n} ---just one character; don't type the quotes and
223don't type the Return key afterward--- to get to the normal start of
224the course.
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225@end ifinfo
226
227@node Help, Help-P, Help-Small-Screen, Getting Started
228@comment node-name, next, previous, up
229@section How to use Info
230
231You are talking to the program Info, for reading documentation.
232
b457dbd9 233@cindex node, in Info documents
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234 Right now you are looking at one @dfn{Node} of Information.
235A node contains text describing a specific topic at a specific
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236level of detail. This node's topic is ``how to use Info''. The mode
237line says that this is node @samp{Help} in the file @file{info}.
26901792 238
b457dbd9 239@cindex header of Info node
26901792 240 The top line of a node is its @dfn{header}. This node's header (look at
b457dbd9 241it now) says that the @samp{Next} node after this one is the node
26901792 242called @samp{Help-P}. An advanced Info command lets you go to any node
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243whose name you know. In the stand-alone Info reader program, the
244header line shows the names of this node and the info file as well.
245In Emacs, the header line is displayed in a special typeface, and it
246doesn't scroll off the screen when you scroll the display. The names
247of this node and of its Info file are omitted by Emacs from the header
248line.
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249
250 Besides a @samp{Next}, a node can have a @samp{Previous} or an
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251@samp{Up} links, or both. As you can see, this node has all of these
252links.
26901792 253
b457dbd9 254@kindex n @r{(Info mode)}
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255 Now it is time to move on to the @samp{Next} node, named @samp{Help-P}.
256
257@format
b457dbd9 258>> Type @kbd{n} to move there. Type just one character;
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259 do not type the quotes and do not type a @key{RET} afterward.
260@end format
261
b457dbd9 262@noindent
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263@samp{>>} in the margin means it is really time to try a command.
264
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265@format
266>> If you have a mouse, and if you already practiced typing @kbd{n}
267 to get to the next node, click now with the right mouse button on
268 the @samp{Next} link to do the same ``the mouse way''.
269@end format
270
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271@node Help-P, Help-^L, Help, Getting Started
272@comment node-name, next, previous, up
273@section Returning to the Previous node
274
b457dbd9 275@kindex p @r{(Info mode)}
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276This node is called @samp{Help-P}. The @samp{Previous} node, as you see,
277is @samp{Help}, which is the one you just came from using the @kbd{n}
278command. Another @kbd{n} command now would take you to the next
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279node, @samp{Help-^L}. In Emacs, @kbd{n} runs the Emacs command
280@code{Info-next}, and @kbd{p} runs @code{Info-prev}.
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281
282@format
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283>> But do not type @kbd{n} yet. First, try the @kbd{p} command,
284 or click the mouse on the @samp{Prev} link, which takes you to the
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285 @samp{Previous} node. When you get there, you can do an @kbd{n}
286 again to return here.
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287@end format
288
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289 If you read this in Emacs, you will see an @samp{Info} item in the
290menu bar, close to its right edge. Clicking your mouse on the
291@samp{Info} menu-bar item opens a menu of commands which include
292@samp{Next} and @samp{Prev} (and also some others which you didn't yet
293learn about).
294
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295 This all probably seems insultingly simple so far, but @emph{do not} be
296led into skimming. Things will get more complicated soon. Also,
297do not try a new command until you are told it is time to. Otherwise,
298you may make Info skip past an important warning that was coming up.
299
300@format
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301>> Now do an @kbd{n}, or click the mouse on the @samp{Next} link, to
302 get to the node @samp{Help-^L} and learn more.
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303@end format
304
305@node Help-^L, Help-M, Help-P, Getting Started
306@comment node-name, next, previous, up
b457dbd9 307@section The Space, DEL, B and ^L commands.
26901792 308
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309 This node's mode line tells you that you are now at node @samp{Help-^L},
310and the header line tells you that @kbd{p} would get you back to
311@samp{Help-P}. The node's title is underlined; it says what the node
312is about (most nodes have titles).
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313
314 This is a big node and it does not all fit on your display screen.
315You can tell that there is more that is not visible because you
316can see the string @samp{--Top-----} rather than @samp{--All----} near
317the bottom right corner of the screen.
318
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319@kindex SPC @r{(Info mode)}
320@kindex DEL @r{(Info mode)}
321@kindex BACKSPACE @r{(Info mode)}
322@findex Info-scroll-up
323@findex Info-scroll-down
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324 The @key{SPC}, @key{BACKSPACE} (or @key{DEL})@footnote{The key which
325we call ``Backspace or DEL'' in this manual is labeled differently on
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326different keyboards. Look for a key which is a little ways above the
327@key{ENTER} or @key{RET} key and which you normally use outside Emacs
328to erase the character before the cursor, i.e.@: the character you
329typed last. It might be labeled @samp{Backspace} or @samp{<-} or
330@samp{DEL}, or sometimes @samp{Delete}.} and @kbd{b} commands exist to
331allow you to ``move around'' in a node that does not all fit on the
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332screen at once. @key{SPC} moves forward, to show what was below the
333bottom of the screen. @key{DEL} or @key{BACKSPACE} moves backward, to
334show what was above the top of the screen (there is not anything above
335the top until you have typed some spaces). In Emacs, @key{SPC} runs
336the command @code{Info-scroll-up}, while @key{BACKSPACE} runs
337@code{Info-scroll-down}.
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338
339@format
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340>> Now try typing a @key{SPC} (afterward, type a @key{BACKSPACE} to
341 return here).
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342@end format
343
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344 When you type the @key{SPC}, the two lines that were at the bottom of
345the screen appear at the top, followed by more lines. @key{DEL} or
346@key{BACKSPACE} takes the two lines from the top and moves them to the
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347bottom, @emph{usually}, but if there are not a full screen's worth of
348lines above them they may not make it all the way to the bottom.
349
350 If you are reading this in Emacs, note that the header line is
351always visible, never scrolling off the display. That way, you can
352always see the @samp{Next}, @samp{Prev}, and @samp{Up} links, and you
353can conveniently go to one of these links from anywhere in the node by
354clicking the mouse on one of these links.
355
356@cindex reading Info documents top to bottom
357@cindex Info documents as tutorials
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358 @key{SPC} and @key{DEL} not only move forward and backward through
359the current node. When these keys hit the beginning or the end of the
360current node, they move to preceding or subsequent nodes.
361Specifically, they scroll through all the nodes in an Info file as a
362single logical sequence. In this sequence, a node's subnodes appear
363following their parent. If a node has a menu, @key{SPC} takes you
364into the subnodes listed in the menu, one by one. Once you reach the
365end of a node, and have seen all of its subnodes, @key{SPC} takes you
366to the next node or to the parent's next node. This is so you could
367read the entire manual top to bottom by just typing @key{SPC}.
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368
369@kindex PAGEUP @r{(Info mode)}
370@kindex PAGEDOWN @r{(Info mode)}
371 Many keyboards nowadays have two scroll keys labeled @samp{PageUp}
372and @samp{PageDown} (or maybe @samp{Prior} and @samp{Next}). If your
373keyboard has these keys, you can use them to move forward and backward
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374through the text, like with @key{SPC} and @key{BACKSPACE}. However,
375unlike @key{SPC} and @key{BACKSPACE}, @key{PAGEUP} and @key{PAGEDOWN}
376keys will never scroll beyond the beginning or the end of the current
377node.
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378
379@kindex C-l @r{(Info mode)}
26901792 380 If your screen is ever garbaged, you can tell Info to print it out
b457dbd9 381again by typing @kbd{C-l} (@kbd{Control-L}, that is---hold down
3c7625c9 382@key{CTRL} and type @kbd{L} or @kbd{l}).
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383
384@format
385>> Type @kbd{C-l} now.
386@end format
387
b457dbd9 388@kindex b @r{(Info mode)}
26901792 389 To move back to the beginning of the node you are on, you can type
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390a lot of @key{BACKSPACE} keys. You can also type simply @kbd{b} for
391beginning.
b457dbd9 392
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393@format
394>> Try that now. (We have put in enough verbiage to push this past
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395 the first screenful, but screens are so big nowadays that perhaps it
396 isn't enough. You may need to shrink your Emacs or Info window.)
3c7625c9 397 Then come back, with @key{SCS}s.
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398@end format
399
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400 If your screen is very tall, all of this node might fit at once.
401In that case, @kbd{b} won't do anything. Sorry; what can we do?
26901792 402
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403@kindex ? @r{(Info mode)}
404@findex Info-summary
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405 You have just learned a considerable number of commands. If you
406want to use one but have trouble remembering which, you should type
79c43dcd 407a @kbd{?} (in Emacs it runs the @code{Info-summary} command) which
b457dbd9 408prints out a brief list of commands. When you are finished looking at
3c7625c9 409the list, make it go away by typing a @key{SPC} repeatedly.
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410
411@format
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412>> Type a @key{?} now. Press @key{SPC} to see consecutive screenfuls of
413 the list until finished. Then type @key{SPC} several times, until
414 it goes away.
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415@end format
416
b457dbd9 417 (If you are using the stand-alone Info reader, type @kbd{C-x 0} to
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418return here, that is---press and hold @key{CTRL}, type an @kbd{x},
419then release @key{CTRL} and @kbd{x}, and press @kbd{0}---a zero, not
b457dbd9 420the letter ``o''.)
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421
422 From now on, you will encounter large nodes without warning, and
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423will be expected to know how to use @key{SPC} and @key{BACKSPACE} to
424move around in them without being told. Since not all terminals have
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425the same size screen, it would be impossible to warn you anyway.
426
427@format
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428>> Now type @kbd{n}, or click the mouse on the @samp{Next} link, to
429 see the description of the @kbd{m} command.
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430@end format
431
432@node Help-M, Help-Adv, Help-^L, Getting Started
433@comment node-name, next, previous, up
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434@section Menus and the @kbd{m} command
435
436@cindex menus in an Info document
437@cindex Info menus
438 With only the @kbd{n} (next) and @kbd{p} (previous) commands for
439moving between nodes, nodes are restricted to a linear sequence.
440Menus allow a branching structure. A menu is a list of other nodes
441you can move to. It is actually just part of the text of the node
442formatted specially so that Info can interpret it. The beginning of a
443menu is always identified by a line which starts with @samp{* Menu:}.
444A node contains a menu if and only if it has a line in it which starts
445that way. The only menu you can use at any moment is the one in the
446node you are in. To use a menu in any other node, you must move to
447that node first.
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448
449 After the start of the menu, each line that starts with a @samp{*}
450identifies one subtopic. The line usually contains a brief name
451for the subtopic (followed by a @samp{:}), the name of the node that talks
452about that subtopic, and optionally some further description of the
453subtopic. Lines in the menu that do not start with a @samp{*} have no
454special meaning---they are only for the human reader's benefit and do
455not define additional subtopics. Here is an example:
456
457@example
b457dbd9 458* Foo: Node about FOO This tells about FOO
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459@end example
460
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461The subtopic name is Foo, and the node describing it is @samp{Node
462about FOO}. The rest of the line is just for the reader's
463Information. [[ But this line is not a real menu item, simply because
464there is no line above it which starts with @samp{* Menu:}.]]
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465
466 When you use a menu to go to another node (in a way that will be
467described soon), what you specify is the subtopic name, the first
468thing in the menu line. Info uses it to find the menu line, extracts
469the node name from it, and goes to that node. The reason that there
470is both a subtopic name and a node name is that the node name must be
471meaningful to the computer and may therefore have to be ugly looking.
472The subtopic name can be chosen just to be convenient for the user to
473specify. Often the node name is convenient for the user to specify
474and so both it and the subtopic name are the same. There is an
475abbreviation for this:
476
477@example
478* Foo:: This tells about FOO
479@end example
480
481@noindent
482This means that the subtopic name and node name are the same; they are
483both @samp{Foo}.
484
485@format
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486>> Now use @key{SPC} to find the menu in this node, then come back to
487 the front with a @kbd{b} and some @key{SPC}s. As you see, a menu is
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488 actually visible in its node. If you cannot find a menu in a node
489 by looking at it, then the node does not have a menu and the
490 @kbd{m} command is not available.
491@end format
492
b457dbd9 493@kindex m @r{(Info mode)}
26901792 494 The command to go to one of the subnodes is @kbd{m}---but @emph{do
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495not do it yet!} Before you use @kbd{m}, you need to learn about
496commands which prompt you for more input. So far, you have learned
497several commands that do not need additional input; when you typed
498one, Info processed it and was instantly ready for another command.
499The @kbd{m} command is different: it is incomplete without the
500@dfn{name of the subtopic}. Once you have typed @kbd{m}, Info tries
501to read the subtopic name.
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502
503 Now look for the line containing many dashes near the bottom of the
504screen. There is one more line beneath that one, but usually it is
505blank. If it is empty, Info is ready for a command, such as @kbd{n}
3c7625c9 506or @kbd{b} or @key{SPC} or @kbd{m}. If that line contains text ending
b457dbd9 507in a colon, it means Info is trying to read more input for the last
26901792 508command. At such times, commands do not work, because Info tries to
b457dbd9 509use them as the input it needs. You must either type your response and
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510finish the command you started, or type @kbd{Control-g} to cancel the
511command. When you have done one of those things, the line becomes
512blank again.
513
b457dbd9 514@findex Info-menu
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515 The command to go to a subnode via a menu is @kbd{m}. After you type
516the @kbd{m}, the line at the bottom of the screen says @samp{Menu item: }.
517You must then type the name of the subtopic you want, and end it with
b457dbd9 518a @key{RET}. In Emacs, @kbd{m} runs the command @code{Info-menu}.
26901792 519
b457dbd9 520@cindex abbreviating Info subnodes
26901792 521 You can abbreviate the subtopic name. If the abbreviation is not
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522unique, the first matching subtopic is chosen. Some menus put
523the shortest possible abbreviation for each subtopic name in capital
524letters, so you can see how much you need to type. It does not
525matter whether you use upper case or lower case when you type the
526subtopic. You should not put any spaces at the end, or inside of the
527item name, except for one space where a space appears in the item in
528the menu.
529
530@cindex completion of Info node names
26901792 531 You can also use the @dfn{completion} feature to help enter the subtopic
3c7625c9 532name. If you type the @key{TAB} key after entering part of a name, it will
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533magically fill in more of the name---as much as follows uniquely from
534what you have entered.
535
536 If you move the cursor to one of the menu subtopic lines, then you do
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537not need to type the argument: you just type a @key{RET}, and it
538stands for the subtopic of the line you are on.
26901792 539
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540Here is a menu to give you a chance to practice. This menu gives you
541three ways of going to one place, Help-FOO:
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542
543@menu
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544* Foo: Help-FOO. A node you can visit for fun.
545* Bar: Help-FOO. Strange! two ways to get to the same place.
546* Help-FOO:: And yet another!
547@end menu
548
549@format
550>> Now type just an @kbd{m} and see what happens:
551@end format
552
553 Now you are ``inside'' an @kbd{m} command. Commands cannot be used
554now; the next thing you will type must be the name of a subtopic.
555
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556 You can change your mind about doing the @kbd{m} by typing
557@kbd{Control-g}.
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558
559@format
560>> Try that now; notice the bottom line clear.
b457dbd9 561@end format
26901792 562
b457dbd9 563@format
26901792 564>> Then type another @kbd{m}.
b457dbd9 565@end format
26901792 566
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567@format
568>> Now type @kbd{BAR}, the item name. Do not type @key{RET} yet.
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569@end format
570
b457dbd9 571 While you are typing the item name, you can use the @key{DEL} (or
3c7625c9 572@key{BACKSPACE}) key to cancel one character at a time if you make a
b457dbd9 573mistake.
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574
575@format
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576>> Press @key{DEL} to cancel the @samp{R}. You could type another @kbd{R}
577 to replace it. But you do not have to, since @samp{BA} is a valid
578 abbreviation.
579@end format
26901792 580
b457dbd9 581@format
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582>> Now you are ready to go. Type a @key{RET}.
583@end format
584
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585 After visiting @samp{Help-FOO}, you should return here.
586
587 Another way to move to the menu subtopic lines and between them is
588to type @key{TAB}. Each time you type a @key{TAB}, you move to the
589next subtopic line. To move to a previous subtopic line, type
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590@kbd{M-@key{TAB}}---that is, press and hold the @key{META} key and then
591press @key{TAB}. (On some keyboards, the @key{META} key might be labeled
592@samp{Alt}.)
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593
594 Once you move cursor to a subtopic line, press @key{RET} to go to
595that subtopic's node.
596
597@cindex mouse support in Info mode
598@kindex Mouse-2 @r{(Info mode)}
599 If your terminal supports a mouse, you have yet another way of going
600to a subtopic. Move your mouse pointer to the subtopic line,
601somewhere between the beginning @samp{*} and the colon @samp{:} which
602ends the subtopic's brief name. You will see the subtopic's name
603change its appearance (usually, its background color will change), and
604the shape of the mouse pointer will change if your platform supports
605that. After a while, if you leave the mouse on that spot, a tooltip
606will pop up saying ``Mouse-2: go to that node''. (If the tooltips are
607turned off or unavailable, this message is printed in the @dfn{echo
3c7625c9 608area}, the bottom screen line where you typed the menu subtopics in
b457dbd9 609response to the prompt.) @kbd{Mouse-2} is the second button of your
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610mouse counting from the left---the rightmost button for two-button
611mice, the middle button for 3-button mice. So pressing @kbd{Mouse-2}
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612while the mouse pointer is on a menu subtopic goes to that subtopic.
613
614@findex Info-mouse-follow-nearest-node
615 More generally, @kbd{Mouse-2} in an Info buffer runs the Emacs
616command @code{Info-mouse-follow-nearest-node}, which finds the nearest
617link to another node and goes there. For example, near a cross
618reference it acts like @kbd{f}, in a menu it acts like @kbd{m}, on the
619node's header line it acts like @kbd{n}, @kbd{p}, or @kbd{u}, etc. At
620end of the node's text @kbd{Mouse-2} moves to the next node, or up if
621there's no next node.
622
623 Here is another way to get to Help-FOO, a menu. You can ignore this
624if you want, or else try it by typing @key{TAB} and then @key{RET}, or
625clicking @kbd{Mouse-2} on it (but then please come back to here).
626
627@menu
628* Help-FOO::
629@end menu
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630
631@format
632>> Type @kbd{n} to see more commands.
633@end format
634
26901792 635@node Help-FOO, , , Help-M
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636@subsection The @kbd{u} command
637
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638 Congratulations! This is the node @samp{Help-FOO}. It has an @samp{Up}
639pointer @samp{Help-M}, the node you just came from via the @kbd{m}
640command. This is the usual convention---the nodes you reach from a menu
641have @samp{Up} nodes that lead back to the menu. Menus move Down in the
642tree, and @samp{Up} moves Up. @samp{Previous}, on the other hand, is
643usually used to ``stay on the same level but go backwards''.
26901792 644
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645@kindex u @r{(Info mode)}
646@findex Info-up
26901792 647 You can go back to the node @samp{Help-M} by typing the command
3c7625c9 648@kbd{u} for ``Up'' (the Emacs command run by @kbd{u} is
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649@code{Info-up}). That puts you at the @emph{front} of the node---to
650get back to where you were reading you have to type some @key{SPC}s.
651(Some Info readers, such as the one built into Emacs, put you at the
652same place where you were reading in @samp{Help-M}.)
653
654 Another way to go Up is to click on the @samp{Up} pointer shown in
655the header line (provided that you have a mouse).
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656
657@format
658>> Now type @kbd{u} to move back up to @samp{Help-M}.
659@end format
660
661@node Help-Adv, Help-Q, Help-M, Getting Started
662@comment node-name, next, previous, up
663@section Some advanced Info commands
664
665 The course is almost over, so please stick with it to the end.
666
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667@kindex l @r{(Info mode)}
668@findex Info-last
669@cindex going back in Info mode
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670 If you have been moving around to different nodes and wish to
671retrace your steps, the @kbd{l} command (@kbd{l} for @dfn{last}) will
672do that, one node-step at a time. As you move from node to node, Info
673records the nodes where you have been in a special history list. The
674@kbd{l} command revisits nodes in the history list; each successive
675@kbd{l} command moves one step back through the history.
676
b457dbd9 677 If you have been following directions, ad @kbd{l} command now will get
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678you back to @samp{Help-M}. Another @kbd{l} command would undo the
679@kbd{u} and get you back to @samp{Help-FOO}. Another @kbd{l} would undo
680the @kbd{m} and get you back to @samp{Help-M}.
681
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682 In Emacs, @kbd{l} runs the command @code{Info-last}.
683
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684@format
685>> Try typing three @kbd{l}'s, pausing in between to see what each
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686 @kbd{l} does. Then follow directions again and you will end up
687 back here.
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688@end format
689
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690 Note the difference between @kbd{l} and @kbd{p}: @kbd{l} moves to
691where @emph{you} last were, whereas @kbd{p} always moves to the node
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692which the header says is the @samp{Previous} node (from this node, the
693@samp{Prev} link leads to @samp{Help-M}).
694
695@kindex d @r{(Info mode)}
696@findex Info-directory
697@cindex go to Directory node
698 The @kbd{d} command (@code{Info-directory} in Emacs) gets you
699instantly to the Directory node. This node, which is the first one
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700you saw when you entered Info, has a menu which leads (directly or
701indirectly, through other menus), to all the nodes that exist. The
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702Directory node lists all the manuals and other Info documents that
703are, or could be, installed on your system.
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704
705@format
b457dbd9 706>> Try doing a @kbd{d}, then do an @kbd{l} to return here (yes,
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707 @emph{do} return).
708@end format
709
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710@kindex t @r{(Info mode)}
711@findex Info-top-node
712@cindex go to Top node
713 The @kbd{t} command moves to the @samp{Top} node of the manual.
714This is useful if you want to browse the manual's main menu, or select
715some specific top-level menu item. The Emacs command run by @kbd{t}
716is @code{Info-top-node}.
717
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718 Sometimes, in Info documentation, you will see a cross reference.
719Cross references look like this: @xref{Help-Cross, Cross}. That is a
720real, live cross reference which is named @samp{Cross} and points at
721the node named @samp{Help-Cross}.
722
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723@kindex f @r{(Info mode)}
724@findex Info-follow-reference
725@cindex cross references in Info documents
726 If you wish to follow a cross reference, you must use the @kbd{f}
727command. The @kbd{f} must be followed by the cross reference name
728(in this case, @samp{Cross}). If the cursor is on or near the cross
729reference, Info suggests the name if the nearest reference in
730parentheses; typing @key{RET} will follow that reference. You can
731also type a different name, if the default is not what you want.
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732While you enter the name, you can use the @key{DEL} (or
733@key{BACKSPACE}) key to edit your input. If you change your mind
734about following any reference, you can use @kbd{Control-g} to cancel
735the command.
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736
737 Completion is available in the @kbd{f} command; you can complete among
3c7625c9 738all the cross reference names in the current node by typing a @key{TAB}.
26901792 739
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740 @kbd{f} runs @code{Info-follow-reference} in Emacs.
741
26901792 742@format
b457dbd9 743>> Type @kbd{f}, followed by @kbd{Cross}, and a @key{RET}.
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744@end format
745
746 To get a list of all the cross references in the current node, you can
b457dbd9 747type @kbd{?} after an @kbd{f}. The @kbd{f} continues to await a
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748cross reference name even after printing the list, so if you don't
749actually want to follow a reference, you should type a @kbd{Control-g}
b457dbd9 750to cancel the @kbd{f}.
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751
752@format
b457dbd9 753>> Type @kbd{f?} to get a list of the cross references in this node. Then
26901792 754 type a @kbd{Control-g} and see how the @samp{f} gives up.
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755@end format
756
757 The @key{TAB} and @kbd{M-@key{TAB}} key, which move between
758subtopics in a menu can move between cross references as well. Once
759the cursor is on a cross reference, you can press @key{RET} to follow
760that reference, just like you do in a menu.
26901792 761
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762 Clicking @kbd{Mouse-2} on or near a cross reference also follows the
763reference. You can see that the cross reference is mouse-sensitive by
764moving the mouse pointer to the reference and watching how the
765underlying text and the mouse pointer change in response.
766
767@format
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768>> Now type @kbd{n} to see the last node of the course.
769@end format
770
771@c If a menu appears at the end of this node, remove it.
772@c It is an accident of the menu updating command.
773
b457dbd9 774@node Advanced Info
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775@chapter Info for Experts
776
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777 This chapter describes various advanced Info commands. (If you are
778using a stand-alone Info reader, there are additional commands
779specific to it, which are documented in several chapters of @ref{Top,,
780GNU Info, info-stnd, GNU Info}.)
781
782 This chapter also explains how to write an Info as distinct from a
783Texinfo file. (However, in most cases, writing a Texinfo file is
784better, since you can use it @emph{both} to generate an Info file and
785to make a printed manual. @xref{Top,, Overview of Texinfo, texinfo,
786Texinfo: The GNU Documentation Format}.)
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787
788@menu
789* Expert:: Advanced Info commands: g, s, e, and 1 - 5.
b457dbd9 790* Info Search:: How to search Info documents for specific subjects.
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791* Add:: Describes how to add new nodes to the hierarchy.
792 Also tells what nodes look like.
793* Menus:: How to add to or create menus in Info nodes.
794* Cross-refs:: How to add cross-references to Info nodes.
795* Tags:: How to make tags tables for Info files.
796* Checking:: Checking an Info File
797* Emacs Info Variables:: Variables modifying the behavior of Emacs Info.
798@end menu
799
b457dbd9 800@node Expert, Info Search, , Advanced Info
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801@comment node-name, next, previous, up
802@section Advanced Info Commands
803
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804Here are some more Info commands that make it easier to move around.
805
806@unnumberedsubsec @kbd{g} goes to a node by name
26901792 807
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808@kindex g @r{(Info mode)}
809@findex Info-goto-node
810@cindex go to a node by name
811 If you know a node's name, you can go there by typing @kbd{g}, the
26901792 812name, and @key{RET}. Thus, @kbd{gTop@key{RET}} would go to the node
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813called @samp{Top} in this file. (This is equivalent to @kbd{t}, see
814@ref{Help-Adv}.) @kbd{gExpert@key{RET}} would come back here.
815@kbd{g} in Emacs runs the command @code{Info-goto-node}.
26901792 816
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817 Unlike @kbd{m}, @kbd{g} does not allow the use of abbreviations.
818But it does allow completion, so you can type @key{TAB} to complete a
819partial node name.
26901792 820
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821@cindex go to another Info file
822 To go to a node in another file, you can include the file name in the
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823node name by putting it at the front, in parentheses. Thus,
824@kbd{g(dir)Top@key{RET}} would go to the Info Directory node, which is
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825the node @samp{Top} in the Info file @file{dir}. Likewise,
826@kbd{g(emacs)Top@key{RET}} goes to the top node of the Emacs manual.
26901792 827
b457dbd9 828 The node name @samp{*} specifies the whole file. So you can look at
26901792 829all of the current file by typing @kbd{g*@key{RET}} or all of any
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830other file with @kbd{g(@var{filename})@key{RET}}.
831
832@unnumberedsubsec @kbd{1} -- @kbd{9} choose a menu subtopic by its number
833
834@kindex 1 @r{through} 9 @r{(Info mode)}
835@findex Info-nth-menu-item
836@cindex select @var{n}'th menu item
837 If you begrudge each character of type-in which your system requires,
838you might like to use the commands @kbd{1}, @kbd{2}, @kbd{3}, @kbd{4},
839@dots{}, @kbd{9}. They are short for the @kbd{m} command together
840with a name of a menu subtopic. @kbd{1} goes through the first item
841in the current node's menu; @kbd{2} goes through the second item, etc.
842In the stand-alone reader, @kbd{0} goes through the last menu item;
843this is so you need not count how many entries are there. In Emacs,
844the digit keys run the command @code{Info-nth-menu-item}.
845
846 If your display supports multiple fonts, and you are using Emacs'
847Info mode to read Info files, the @samp{*} for the fifth menu item
848stands out, either in color or in some other attribute, such as
849underline, and so is the @samp{*} for the ninth item; this makes it
850easy to see at a glance which number to use for an item.
851
852 Some terminals don't support colors or underlining. If you need to
26901792 853actually count items, it is better to use @kbd{m} instead, and specify
b457dbd9 854the name, or use @key{TAB} to quickly move between menu items.
26901792 855
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856@unnumberedsubsec @kbd{e} makes Info document editable
857
858@kindex e @r{(Info mode)}
859@findex Info-edit
860@cindex edit Info document
861 The Info command @kbd{e} changes from Info mode to an ordinary
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862Emacs editing mode, so that you can edit the text of the current node.
863Type @kbd{C-c C-c} to switch back to Info. The @kbd{e} command is allowed
864only if the variable @code{Info-enable-edit} is non-@code{nil}.
865
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866 The @kbd{e} command only works in Emacs, where it runs the command
867@code{Info-edit}. The stand-alone Info reader doesn't allow you to
868edit the Info file, so typing @kbd{e} there goes to the end of the
869current node.
870
871@node Info Search, Add, Expert, Advanced Info
872@comment node-name, next, previous, up
873@section How to search Info documents for specific subjects
874
875@cindex searching Info documents
876@cindex Info document as a reference
877 The commands which move between and inside nodes allow you to read
878the entire manual or its large portions. But what if you need to find
879some information in the manual as fast as you can, and you don't know
880or don't remember in what node to look for it? This need arises when
881you use a manual as a @dfn{reference}, or when it is impractical to
882read the entire manual before you start using the programs it
883describes.
884
885 Info has powerful searching facilities that let you find things
886quickly. You can search either the manual indices or its text.
887
888@kindex i @r{(Info mode)}
889@findex Info-index
890 Since most subjects related to what the manual describes should be
891indexed, you should try the index search first. The @kbd{i} command
892prompts you for a subject and then looks up that subject in the
893indices. If it finds an index entry with the subject you typed, it
894goes to the node to which that index entry points. You should browse
895through that node to see whether the issue you are looking for is
896described there. If it isn't, type @kbd{,} one or more times to go
897through additional index entries which match your subject.
898
899 The @kbd{i} command finds all index entries which include the string
900you typed @emph{as a substring}. For each match, Info shows in the
901echo area the full index entry it found. Often, the text of the full
902index entry already gives you enough information to decide whether it
903is relevant to what you are looking for, so we recommend that you read
904what Emacs shows in the echo are before looking at the node it
905displays.
906
907 Since @kbd{i} looks for a substring, you can search for subjects even
908if you are not sure how they are spelled in the index. For example,
909suppose you want to find something that is pertinent to commands which
910complete partial input (e.g., when you type @key{TAB}). If you want
911to catch index entries that refer to ``complete'', ``completion'', and
912``completing'', you could type @kbd{icomplet@key{RET}}.
913
914 Info documents which describe programs should index the commands,
915options, and key sequences that the program provides. If you are
916looking for a description of a command, an option, or a key, just type
917their names when @kbd{i} prompts you for a topic. For example, if you
918want to read the description of what the @kbd{C-f} key does, type
919@kbd{iC-f@key{RET}}. Here @kbd{C-f} are 3 literal characters
920@samp{C}, @samp{-}, and @samp{f}, not the ``Control-f'' command key
921you type inside Emacs to run the command bound to @kbd{C-f}.
922
923 In Emacs, @kbd{i} runs the command @code{Info-index}.
924
925@kindex s @r{(Info mode)}
926@findex Info-search
927 The @kbd{s} command allows you to search a whole file for a string.
928It switches to the next node if and when that is necessary. You
929type @kbd{s} followed by the string to search for, terminated by
930@key{RET}. To search for the same string again, just @kbd{s} followed
931by @key{RET} will do. The file's nodes are scanned in the order
932they are in in the file, which has no necessary relationship to the
933order that they may be in the tree structure of menus and @samp{next}
934pointers. But normally the two orders are not very different. In any
935case, you can always do a @kbd{b} to find out what node you have
936reached, if the header is not visible (this can happen, because @kbd{s}
937puts your cursor at the occurrence of the string, not at the beginning
938of the node).
939
940@kindex M-s @r{(Info mode)}
941 In Emacs, @kbd{Meta-s} is equivalent to @kbd{s}. That is for
942compatibility with other GNU packages that use @kbd{M-s} for a similar
943kind of search command. Both @kbd{s} and @kbd{M-s} run in Emacs the
944command @code{Info-search}.
945
946
947@node Add, Menus, Info Search, Advanced Info
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948@comment node-name, next, previous, up
949@section Adding a new node to Info
950
951To add a new topic to the list in the Info directory, you must:
b457dbd9 952
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953@enumerate
954@item
955Create some nodes, in some file, to document that topic.
956@item
957Put that topic in the menu in the directory. @xref{Menus, Menu}.
958@end enumerate
959
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960 Usually, the way to create the nodes is with Texinfo (@pxref{Top,,
961Overview of Texinfo, texinfo, Texinfo: The GNU Documentation Format});
962this has the advantage that you can also make a printed manual from
963them. However, if you want to edit an Info file, here is how.
26901792 964
b457dbd9 965@cindex node delimiters
26901792 966 The new node can live in an existing documentation file, or in a new
79c43dcd 967one. It must have a @samp{^_} character before it (invisible to the
26901792 968user; this node has one but you cannot see it), and it ends with either
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969a @samp{^_}, a @samp{^L} (``formfeed''), or the end of file.@footnote{If
970you put in a @samp{^L} to end a new node, be sure that there is a
971@samp{^_} after it to start the next one, since @samp{^L} cannot
972@emph{start} a node. Also, a nicer way to make a node boundary be a
973page boundary as well is to put a @samp{^L} @emph{right after} the
974@samp{^_}.}
975
976 The @samp{^_} starting a node must be followed by a newline or a
977@samp{^L} newline, after which comes the node's header line. The header
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978line must give the node's name (by which Info finds it), and state the
979names of the @samp{Next}, @samp{Previous}, and @samp{Up} nodes (if there
980are any). As you can see, this node's @samp{Up} node is the node
981@samp{Top}, which points at all the documentation for Info. The
982@samp{Next} node is @samp{Menus}.
983
984@cindex node header line format
985@cindex format of node headers
986 The keywords @dfn{Node}, @dfn{Next}, @dfn{Previous}, and @dfn{Up}
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987may appear in any order, anywhere in the header line, but the
988recommended order is the one in this sentence. Each keyword must be
989followed by a colon, spaces and tabs, and then the appropriate name.
990The name may be terminated with a tab, a comma, or a newline. A space
991does not end it; node names may contain spaces. The case of letters
992in the names is insignificant.
993
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994@cindex node name format
995@cindex Directory node
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996 A node name has two forms. A node in the current file is named by
997what appears after the @samp{Node: } in that node's first line. For
998example, this node's name is @samp{Add}. A node in another file is
999named by @samp{(@var{filename})@var{node-within-file}}, as in
1000@samp{(info)Add} for this node. If the file name starts with ``./'',
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1001then it is relative to the current directory; otherwise, it is
1002relative starting from the standard directory for Info files of your
1003site. The name @samp{(@var{filename})Top} can be abbreviated to just
1004@samp{(@var{filename})}. By convention, the name @samp{Top} is used
1005for the ``highest'' node in any single file---the node whose @samp{Up}
1006points out of the file. The @samp{Directory} node is @file{(dir)}, it
1007points to a file @file{dir} which holds a large menu listing all the
1008Info documents installed on your site. The @samp{Top} node of a
1009document file listed in the @samp{Directory} should have an @samp{Up:
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1010(dir)} in it.
1011
b457dbd9 1012@cindex unstructured documents
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1013 The node name @kbd{*} is special: it refers to the entire file.
1014Thus, @kbd{g*} shows you the whole current file. The use of the
1015node @kbd{*} is to make it possible to make old-fashioned,
1016unstructured files into nodes of the tree.
1017
1018 The @samp{Node:} name, in which a node states its own name, must not
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1019contain a file name, since when Info searches for a node, it does not
1020expect a file name to be there. The @samp{Next}, @samp{Previous} and
1021@samp{Up} names may contain them. In this node, since the @samp{Up}
1022node is in the same file, it was not necessary to use one.
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1023
1024 Note that the nodes in this file have a file name in the header
1025line. The file names are ignored by Info, but they serve as comments
1026to help identify the node for the user.
1027
1028@node Menus, Cross-refs, Add, Advanced Info
1029@comment node-name, next, previous, up
1030@section How to Create Menus
1031
b457dbd9 1032 Any node in the Info hierarchy may have a @dfn{menu}---a list of subnodes.
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1033The @kbd{m} command searches the current node's menu for the topic which it
1034reads from the terminal.
1035
b457dbd9 1036@cindex menu and menu entry format
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1037 A menu begins with a line starting with @samp{* Menu:}. The rest of the
1038line is a comment. After the starting line, every line that begins
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1039with a @samp{* } lists a single topic. The name of the topic--what
1040the user must type at the @kbd{m}'s command prompt to select this
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1041topic---comes right after the star and space, and is followed by a
1042colon, spaces and tabs, and the name of the node which discusses that
1043topic. The node name, like node names following @samp{Next}, @samp{Previous}
1044and @samp{Up}, may be terminated with a tab, comma, or newline; it may also
1045be terminated with a period.
1046
1047 If the node name and topic name are the same, then rather than
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1048giving the name twice, the abbreviation @samp{* @var{name}::} may be
1049used (and should be used, whenever possible, as it reduces the visual
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1050clutter in the menu).
1051
1052 It is considerate to choose the topic names so that they differ
1053from each other very near the beginning---this allows the user to type
1054short abbreviations. In a long menu, it is a good idea to capitalize
1055the beginning of each item name which is the minimum acceptable
1056abbreviation for it (a long menu is more than 5 or so entries).
1057
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1058 The nodes listed in a node's menu are called its ``subnodes'', and it
1059is their ``superior''. They should each have an @samp{Up:} pointing at
1060the superior. It is often useful to arrange all or most of the subnodes
1061in a sequence of @samp{Next} and @samp{Previous} pointers so that
1062someone who wants to see them all need not keep revisiting the Menu.
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1063
1064 The Info Directory is simply the menu of the node @samp{(dir)Top}---that
1065is, node @samp{Top} in file @file{.../info/dir}. You can put new entries
1066in that menu just like any other menu. The Info Directory is @emph{not} the
1067same as the file directory called @file{info}. It happens that many of
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1068Info's files live in that file directory, but they do not have to; and
1069files in that directory are not automatically listed in the Info
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1070Directory node.
1071
1072 Also, although the Info node graph is claimed to be a ``hierarchy'',
1073in fact it can be @emph{any} directed graph. Shared structures and
1074pointer cycles are perfectly possible, and can be used if they are
1075appropriate to the meaning to be expressed. There is no need for all
1076the nodes in a file to form a connected structure. In fact, this file
1077has two connected components. You are in one of them, which is under
1078the node @samp{Top}; the other contains the node @samp{Help} which the
1079@kbd{h} command goes to. In fact, since there is no garbage
1080collector, nothing terrible happens if a substructure is not pointed
1081to, but such a substructure is rather useless since nobody can
1082ever find out that it exists.
1083
1084@node Cross-refs, Tags, Menus, Advanced Info
1085@comment node-name, next, previous, up
1086@section Creating Cross References
1087
b457dbd9 1088@cindex cross reference format
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1089 A cross reference can be placed anywhere in the text, unlike a menu
1090item which must go at the front of a line. A cross reference looks
b457dbd9 1091like a menu item except that it has @samp{*note} instead of @samp{*}.
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1092It @emph{cannot} be terminated by a @samp{)}, because @samp{)}'s are
1093so often part of node names. If you wish to enclose a cross reference
1094in parentheses, terminate it with a period first. Here are two
1095examples of cross references pointers:
1096
1097@example
1098*Note details: commands. (See *note 3: Full Proof.)
1099@end example
1100
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1101@noindent
1102@emph{These are just examples.} The places they ``lead to'' do not
1103really exist!
26901792 1104
768e4b74
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1105@menu
1106* Help-Cross:: Target of a cross-reference.
1107@end menu
1108
1109
1110@node Help-Cross, , , Cross-refs
1111@subsection The node reached by the cross reference in Info
1112
1113 This is the node reached by the cross reference named @samp{Cross}.
1114
1115 While this node is specifically intended to be reached by a cross
1116reference, most cross references lead to nodes that ``belong''
1117someplace else far away in the structure of an Info document. So you
1118cannot expect this node to have a @samp{Next}, @samp{Previous} or
1119@samp{Up} links pointing back to where you came from. In general, the
1120@kbd{l} (el) command is the only way to get back there.
1121
1122@format
1123>> Type @kbd{l} to return to the node where the cross reference was.
1124@end format
1125
1126@node Help-Q, , Help-Adv, Getting Started
1127@comment node-name, next, previous, up
1128@section Quitting Info
1129
1130@kindex q @r{(Info mode)}
1131@findex Info-exit
1132@cindex quitting Info mode
1133 To get out of Info, back to what you were doing before, type @kbd{q}
1134for @dfn{Quit}. This runs @code{Info-exit} in Emacs.
1135
1136 This is the end of the basic course on using Info. You have learned
1137how to move in an Info document, and how to follow menus and cross
1138references. This makes you ready for reading manuals top to bottom,
1139as new users should do when they learn a new package.
1140
1141 Another set of Info commands is useful when you need to find
1142something quickly in a manual---that is, when you need to use a manual
1143as a reference rather than as a tutorial. We urge you to make learn
1144these search commands as well. If you want to do that now, follow this
1145cross reference to @ref{Info Search}.
1146
1147Yet another set of commands are meant for experienced users; you can
1148find them by looking in the Directory node for documentation on Info.
1149Finding them will be a good exercise in using Info in the usual
1150manner.
1151
1152@format
1153>> Type @kbd{d} to go to the Info directory node; then type
1154 @kbd{mInfo} and Return, to get to the node about Info and
1155 see what other help is available.
1156@end format
1157
1158
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1159@node Tags, Checking, Cross-refs, Advanced Info
1160@comment node-name, next, previous, up
1161@section Tags Tables for Info Files
1162
b457dbd9 1163@cindex tags tables in info files
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1164 You can speed up the access to nodes of a large Info file by giving
1165it a tags table. Unlike the tags table for a program, the tags table for
b457dbd9 1166an Info file lives inside the file itself and is used
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1167automatically whenever Info reads in the file.
1168
b457dbd9 1169@findex Info-tagify
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1170 To make a tags table, go to a node in the file using Emacs Info mode and type
1171@kbd{M-x Info-tagify}. Then you must use @kbd{C-x C-s} to save the
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1172file. Info files produced by the @code{makeinfo} command that is part
1173of the Texinfo package always have tags tables to begin with.
26901792 1174
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1175@cindex stale tags tables
1176@cindex update Info tags table
26901792 1177 Once the Info file has a tags table, you must make certain it is up
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1178to date. If you edit an Info file directly (as opposed to editing its
1179Texinfo source), and, as a result of deletion of text, any node moves back
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1180more than a thousand characters in the file from the position
1181recorded in the tags table, Info will no longer be able to find that
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1182node. To update the tags table, use the @code{Info-tagify} command
1183again.
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1184
1185 An Info file tags table appears at the end of the file and looks like
1186this:
1187
1188@example
b457dbd9 1189^_^L
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1190Tag Table:
1191File: info, Node: Cross-refs^?21419
1192File: info, Node: Tags^?22145
1193^_
1194End Tag Table
1195@end example
1196
1197@noindent
1198Note that it contains one line per node, and this line contains
1199the beginning of the node's header (ending just after the node name),
79c43dcd 1200a @samp{DEL} character, and the character position in the file of the
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1201beginning of the node.
1202
b457dbd9 1203
26901792 1204@node Checking, Emacs Info Variables, Tags, Advanced Info
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1205@section Checking an Info File
1206
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1207When creating an Info file, it is easy to forget the name of a node when
1208you are making a pointer to it from another node. If you put in the
1209wrong name for a node, this is not detected until someone tries to go
1210through the pointer using Info. Verification of the Info file is an
1211automatic process which checks all pointers to nodes and reports any
1212pointers which are invalid. Every @samp{Next}, @samp{Previous}, and
26901792 1213@samp{Up} is checked, as is every menu item and every cross reference. In
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1214addition, any @samp{Next} which does not have a @samp{Previous} pointing
1215back is reported. Only pointers within the file are checked, because
1216checking pointers to other files would be terribly slow. But those are
1217usually few.
26901792 1218
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1219@findex Info-validate
1220To check an Info file, do @kbd{M-x Info-validate} while looking at any
1221node of the file with Emacs Info mode.
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1222
1223@node Emacs Info Variables, , Checking, Advanced Info
1224@section Emacs Info-mode Variables
1225
b457dbd9 1226The following variables may modify the behavior of Info-mode in Emacs;
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1227you may wish to set one or several of these variables interactively, or
1228in your @file{~/.emacs} init file. @xref{Examining, Examining and Setting
1229Variables, Examining and Setting Variables, emacs, The GNU Emacs
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1230Manual}. The stand-alone Info reader program has its own set of
1231variables, described in @ref{Variables,, Manipulating Variables,
1232info-stnd, GNU Info}.
26901792 1233
b457dbd9 1234@vtable @code
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1235@item Info-directory-list
1236The list of directories to search for Info files. Each element is a
79148ea7
GM
1237string (directory name) or @code{nil} (try default directory). If not
1238initialized Info uses the environment variable @env{INFOPATH} to
1239initialize it, or @code{Info-default-directory-list} if there is no
1240@env{INFOPATH} variable in the environment.
1241
1242@item Info-additional-directory-list
1243A list of additional directories to search for Info documentation files.
1244These directories are not searched for merging the @file{dir} file.
26901792 1245
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1246@item Info-fontify
1247When set to a non-@code{nil} value, enables highlighting of Info
1248files. The default is @code{t}. You can change how the highlighting
1249looks by customizing the faces @code{info-node}, @code{info-menu-5},
1250@code{info-xref}, @code{info-header-xref}, @code{info-header-node},
1251@code{info-title-@var{n}-face} (where @var{n} is the level of the
1252section, a number between 1 and 4), and @code{info-menu-header}. To
1253customize a face, type @kbd{M-x customize-face @key{RET} @var{face}
1254@key{RET}}, where @var{face} is one of the face names listed here.
1255
1256@item Info-use-header-line
1257If non-@code{nil}, Emacs puts in the Info buffer a header line showing
1258the @samp{Next}, @samp{Prev}, and @samp{Up} links. A header line does
1259not scroll with the rest of the buffer, making these links always
1260visible.
1261
1262@item Info-scroll-prefer-subnodes
3c7625c9
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1263If set to a non-@code{nil} value, @key{SPC} and @key{BACKSPACE} (or
1264@key{DEL}) keys in a menu visit subnodes of the current node before
1265scrolling to its end or beginning, respectively. For example, if the
1266node's menu appears on the screen, the next @key{SPC} moves to a
1267subnode indicated by the following menu item. Setting this option to
1268@code{nil} results in behavior similar to the stand-alone Info reader
1269program, which visits the first subnode from the menu only when you
1270hit the end of the current node. The default is @code{t}.
79148ea7 1271
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1272@item Info-enable-active-nodes
1273When set to a non-@code{nil} value, allows Info to execute Lisp code
1274associated with nodes. The Lisp code is executed when the node is
1275selected. The Lisp code to be executed should follow the node
79c43dcd 1276delimiter (the @samp{DEL} character) and an @samp{execute: } tag, like
3c7625c9 1277this:
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1279@example
1280^_execute: (message "This is an active node!")
1281@end example
1282
1283@item Info-enable-edit
1284Set to @code{nil}, disables the @samp{e} (@code{Info-edit}) command. A
1285non-@code{nil} value enables it. @xref{Add, Edit}.
1286@end vtable
1287
1288
1289@node Creating an Info File
1290@chapter Creating an Info File from a Texinfo File
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1291
1292@code{makeinfo} is a utility that converts a Texinfo file into an Info
1293file; @code{texinfo-format-region} and @code{texinfo-format-buffer} are
1294GNU Emacs functions that do the same.
1295
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1296@xref{Top,, Overview of Texinfo, texinfo, Texinfo: The GNU
1297Documentation Format}, to learn how to write a Texinfo file.
1298
1299@xref{Creating an Info File,,, texinfo, Texinfo: The GNU Documentation
1300Format}, to learn how to create an Info file from a Texinfo file.
1301
1302@xref{Installing an Info File,,, texinfo, Texinfo: The GNU
1303Documentation Format}, to learn how to install an Info file after you
1304have created one.
1305
1306@node Index
1307@unnumbered Index
1308
1309This is an alphabetical listing of all the commands, variables, and
1310topics discussed in this document.
26901792 1311
b457dbd9 1312@printindex cp
26901792 1313
26901792 1314@bye