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diff --git a/doc/info.texi b/doc/info.texi new file mode 100644 index 0000000..62c4c85 --- /dev/null +++ b/doc/info.texi @@ -0,0 +1,1511 @@ +\input texinfo.tex @c -*-texinfo-*- +@c We must \input texinfo.tex instead of texinfo, otherwise make +@c distcheck in the Texinfo distribution fails, because the texinfo Info +@c file is made first, and texi2dvi must include . first in the path. +@comment %**start of header +@setfilename info.info +@settitle Info +@syncodeindex fn cp +@syncodeindex vr cp +@syncodeindex ky cp +@comment %**end of header + +@copying +This file describes how to use Info, the on-line, menu-driven GNU +documentation system. + +Copyright @copyright{} 1989, 1992, 1996, 1997, 1998, 1999, 2000, 2001, +2002, 2003, 2004, 2005, 2006, 2007, 2008 Free Software Foundation, Inc. + +@quotation +Permission is granted to copy, distribute and/or modify this document +under the terms of the GNU Free Documentation License, Version 1.2 or +any later version published by the Free Software Foundation; with no +Invariant Sections, with the Front-Cover texts being ``A GNU +Manual,'' and with the Back-Cover Texts as in (a) below. A copy of the +license is included in the section entitled ``GNU Free Documentation +License'' in the Emacs manual. + +(a) The FSF's Back-Cover Text is: ``You have freedom to copy and +modify this GNU Manual, like GNU software. Buying copies from GNU +Press supports the FSF in developing GNU and promoting software +freedom.'' + +This document is part of a collection distributed under the GNU Free +Documentation License. If you want to distribute this document +separately from the collection, you can do so by adding a copy of the +license to the document, as described in section 6 of the license. +@end quotation +@end copying + +@dircategory Texinfo documentation system +@direntry +* Info: (info). How to use the documentation browsing system. +@end direntry + +@titlepage +@title Info +@subtitle The online, hyper-text GNU documentation system +@author Brian Fox +@author and the GNU Texinfo community +@page +@vskip 0pt plus 1filll +@insertcopying +@end titlepage + +@contents + +@ifnottex +@node Top +@top Info: An Introduction + +The GNU Project distributes most of its on-line manuals in the +@dfn{Info format}, which you read using an @dfn{Info reader}. You are +probably using an Info reader to read this now. + +There are two primary Info readers: @code{info}, a stand-alone program +designed just to read Info files (@pxref{Top,,Stand-alone Info, +info-stnd, GNU Info}), and the @code{info} package in GNU Emacs, a +general-purpose editor. At present, only the Emacs reader supports +using a mouse. + +@ifinfo +If you are new to the Info reader and want to learn how to use it, +type the command @kbd{h} now. It brings you to a programmed +instruction sequence. + +To read about advanced Info commands, type @kbd{n} twice. This +brings you to @cite{Advanced Info Commands}, skipping over the `Getting +Started' chapter. +@end ifinfo +@end ifnottex + +@menu +* Getting Started:: Getting started using an Info reader. +* Advanced:: Advanced Info commands. +* Expert Info:: Info commands for experts. +* Index:: An index of topics, commands, and variables. +@end menu + +@node Getting Started, Advanced, Top, Top +@comment node-name, next, previous, up +@chapter Getting Started + +This first part of this Info manual describes how to get around inside +of Info. The second part of the manual describes various advanced +Info commands. The third part briefly explains how to generate Info +files from Texinfo files, and describes how to write an Info file +by hand. + +@ifnotinfo +This manual is primarily designed for browsing with an Info reader +program on a computer, so that you can try Info commands while reading +about them. Reading it on paper or with an HTML browser is less +effective, since you must take it on faith that the commands described +really do what the manual says. By all means go through this manual +now that you have it; but please try going through the on-line version +as well. + +@cindex Info reader, how to invoke +@cindex entering Info +There are two ways of looking at the online version of this manual: + +@enumerate +@item +Type @code{info} at your shell's command line. This approach uses a +stand-alone program designed just to read Info files. + +@item +Type @code{emacs} at the command line; then type @kbd{C-h i} +(@kbd{Control-h}, followed by @kbd{i}). This approach uses the Info +mode of the Emacs editor. +@end enumerate + +In either case, then type @kbd{mInfo} (just the letters), followed by +@key{RET}---the ``Return'' or ``Enter'' key. At this point, you should +be ready to follow the instructions in this manual as you read them on +the screen. +@c FIXME! (pesch@cygnus.com, 14 dec 1992) +@c Is it worth worrying about what-if the beginner goes to somebody +@c else's Emacs session, which already has an Info running in the middle +@c of something---in which case these simple instructions won't work? +@end ifnotinfo + +@menu +* Help-Small-Screen:: Starting Info on a Small Screen. +* Help:: How to use Info. +* Help-P:: Returning to the Previous node. +* Help-^L:: The Space, DEL, B and ^L commands. +* Help-Inv:: Invisible text in Emacs Info. +* Help-M:: Menus. +* Help-Xref:: Following cross-references. +* Help-Int:: Some intermediate Info commands. +* Help-Q:: Quitting Info. +@end menu + +@node Help-Small-Screen +@section Starting Info on a Small Screen + +@ifnotinfo +(In Info, you only see this section if your terminal has a small +number of lines; most readers pass by it without seeing it.) +@end ifnotinfo + +@cindex small screen, moving around +Since your terminal has a relatively small number of lines on its +screen, it is necessary to give you special advice at the beginning. + +If the entire text you are looking at fits on the screen, the text +@samp{All} will be displayed at the bottom of the screen. In the +stand-alone Info reader, it is displayed at the bottom right corner of +the screen; in Emacs, it is displayed on the modeline. If you see the +text @samp{Top} instead, it means that there is more text below that +does not fit. To move forward through the text and see another screen +full, press @key{SPC}, the Space bar. To move back up, press the key +labeled @samp{Backspace} or @samp{DEL} (on some keyboards, this key +might be labeled @samp{Delete}). + +@ifinfo +Here are 40 lines of junk, so you can try @key{SPC} and @key{DEL} and +see what they do. At the end are instructions of what you should do +next. + +@format +This is line 20 +This is line 21 +This is line 22 +This is line 23 +This is line 24 +This is line 25 +This is line 26 +This is line 27 +This is line 28 +This is line 29 +This is line 30 +This is line 31 +This is line 32 +This is line 33 +This is line 34 +This is line 35 +This is line 36 +This is line 37 +This is line 38 +This is line 39 +This is line 40 +This is line 41 +This is line 42 +This is line 43 +This is line 44 +This is line 45 +This is line 46 +This is line 47 +This is line 48 +This is line 49 +This is line 50 +This is line 51 +This is line 52 +This is line 53 +This is line 54 +This is line 55 +This is line 56 +This is line 57 +This is line 58 +This is line 59 +@end format + +If you have managed to get here, go back to the beginning with +@kbd{DEL} (or @key{BACKSPACE}), and come back here again, then you +understand the about the @samp{Space} and @samp{Backspace} keys. So +now type an @kbd{n}---just one character; don't type the quotes and +don't type the Return key afterward---to get to the normal start of +the course. +@end ifinfo + +@node Help, Help-P, Help-Small-Screen, Getting Started +@comment node-name, next, previous, up +@section How to use Info + +You are talking to the program Info, for reading documentation. + + There are two ways to use Info: from within Emacs or as a +stand-alone reader that you can invoke from a shell using the command +@command{info}. + +@cindex node, in Info documents + Right now you are looking at one @dfn{Node} of Information. +A node contains text describing a specific topic at a specific +level of detail. This node's topic is ``how to use Info''. The mode +line says that this is node @samp{Help} in the file @file{info}. + +@cindex header of Info node + The top line of a node is its @dfn{header}. This node's header +(look at it now) says that the @samp{Next} node after this one is the +node called @samp{Help-P}. An advanced Info command lets you go to +any node whose name you know. In the stand-alone Info reader program, +the header line shows the names of this node and the Info file as +well. In Emacs, the header line is displayed with a special typeface, +and remains at the top of the window all the time even if you scroll +through the node. + + Besides a @samp{Next}, a node can have a @samp{Previous} link, or an +@samp{Up} link, or both. As you can see, this node has all of these +links. + +@kindex n @r{(Info mode)} + Now it is time to move on to the @samp{Next} node, named @samp{Help-P}. + +@format +>> Type @kbd{n} to move there. Type just one character; + do not type the quotes and do not type a @key{RET} afterward. +@end format + +@noindent +@samp{>>} in the margin means it is really time to try a command. + +@format +>> If you are in Emacs and have a mouse, and if you already practiced + typing @kbd{n} to get to the next node, click now with the left + mouse button on the @samp{Next} link to do the same ``the mouse way''. +@end format + +@node Help-P, Help-^L, Help, Getting Started +@comment node-name, next, previous, up +@section Returning to the Previous node + +@kindex p @r{(Info mode)} +This node is called @samp{Help-P}. The @samp{Previous} node, as you see, +is @samp{Help}, which is the one you just came from using the @kbd{n} +command. Another @kbd{n} command now would take you to the next +node, @samp{Help-^L}. + +@format +>> But do not type @kbd{n} yet. First, try the @kbd{p} command, or + (in Emacs) click on the @samp{Prev} link. That takes you to + the @samp{Previous} node. Then use @kbd{n} to return here. +@end format + + If you read this in Emacs, you will see an @samp{Info} item in the +menu bar, close to its right edge. Clicking the mouse on the +@samp{Info} menu-bar item opens a menu of commands which include +@samp{Next} and @samp{Previous} (and also some others which you didn't yet +learn about). + + This all probably seems insultingly simple so far, but @emph{please +don't} start skimming. Things will get complicated soon enough! +Also, please do not try a new command until you are told it is time +to. You could make Info skip past an important warning that was +coming up. + +@format +>> Now do an @kbd{n}, or (in Emacs) click the middle mouse button on + the @samp{Next} link, to get to the node @samp{Help-^L} and learn more. +@end format + +@node Help-^L, Help-Inv, Help-P, Getting Started +@comment node-name, next, previous, up +@section The Space, DEL, B and ^L commands + + This node's mode line tells you that you are now at node +@samp{Help-^L}, and the header line tells you that @kbd{p} would get +you back to @samp{Help-P}. The node's title is highlighted and may be +underlined as well; it says what the node is about. + + This is a big node and it does not all fit on your display screen. +You can tell that there is more that is not visible because you +can see the text @samp{Top} rather than @samp{All} near the bottom of +the screen. + +@kindex SPC @r{(Info mode)} +@kindex DEL @r{(Info mode)} +@kindex BACKSPACE @r{(Info mode)} +@findex Info-scroll-up +@findex Info-scroll-down + The @key{SPC}, @key{BACKSPACE} (or @key{DEL})@footnote{The key which +we call ``Backspace or DEL'' in this manual is labeled differently on +different keyboards. Look for a key which is a little ways above the +@key{ENTER} or @key{RET} key and which you normally use outside Emacs +to erase the character before the cursor, i.e.@: the character you +typed last. It might be labeled @samp{Backspace} or @samp{<-} or +@samp{DEL}, or sometimes @samp{Delete}.} and @kbd{b} commands exist to +allow you to ``move around'' in a node that does not all fit on the +screen at once. @key{SPC} moves forward, to show what was below the +bottom of the screen. @key{DEL} or @key{BACKSPACE} moves backward, to +show what was above the top of the screen (there is not anything above +the top until you have typed some spaces). + +@format +>> Now try typing a @key{SPC} (afterward, type a @key{BACKSPACE} to + return here). +@end format + + When you type the @key{SPC}, the two lines that were at the bottom of +the screen appear at the top, followed by more lines. @key{DEL} or +@key{BACKSPACE} takes the two lines from the top and moves them to the +bottom, @emph{usually}, but if there are not a full screen's worth of +lines above them they may not make it all the way to the bottom. + + If you are reading this in Emacs, note that the header line is +always visible, never scrolling off the display. That way, you can +always see the @samp{Next}, @samp{Prev}, and @samp{Up} links, and you +can conveniently go to one of these links at any time by +clicking the middle mouse button on the link. + +@cindex reading Info documents top to bottom +@cindex Info documents as tutorials + @key{SPC} and @key{DEL} not only move forward and backward through +the current node. They also move between nodes. @key{SPC} at the end +of a node moves to the next node; @key{DEL} (or @key{BACKSPACE}) at +the beginning of a node moves to the previous node. In effect, these +commands scroll through all the nodes in an Info file as a single +logical sequence. You can read an entire manual top to bottom by just +typing @key{SPC}, and move backward through the entire manual from +bottom to top by typing @key{DEL} (or @key{BACKSPACE}). + + In this sequence, a node's subnodes appear following their parent. +If a node has a menu, @key{SPC} takes you into the subnodes listed in +the menu, one by one. Once you reach the end of a node, and have seen +all of its subnodes, @key{SPC} takes you to the next node or to the +parent's next node. + +@kindex PAGEUP @r{(Info mode)} +@kindex PAGEDOWN @r{(Info mode)} + Many keyboards nowadays have two scroll keys labeled @samp{PageUp} +and @samp{PageDown} (or maybe @samp{Prior} and @samp{Next}). If your +keyboard has these keys, you can use them to move forward and backward +through the text of one node, like @key{SPC} and @key{BACKSPACE} (or +@key{DEL}). However, @key{PAGEUP} and @key{PAGEDOWN} keys never +scroll beyond the beginning or the end of the current node. + +@kindex C-l @r{(Info mode)} + If your screen is ever garbaged, you can tell Info to display it +again by typing @kbd{C-l} (@kbd{Control-L}---that is, hold down +@key{CTRL} and type @kbd{L} or @kbd{l}). + +@format +>> Type @kbd{C-l} now. +@end format + +@kindex b @r{(Info mode)} + To move back to the beginning of the node you are on, you can type +the @key{BACKSPACE} key (or @key{DEL}) many times. You can also type +@kbd{b} just once. @kbd{b} stands for ``beginning.'' + +@format +>> Try that now. (We have put in enough verbiage to push this past + the first screenful, but screens are so big nowadays that perhaps it + isn't enough. You may need to shrink your Emacs or Info window.) + Then come back, by typing @key{SPC} one or more times. +@end format + +@kindex ? @r{(Info mode)} +@findex Info-summary + You have just learned a considerable number of commands. If you +want to use one but have trouble remembering which, you should type +@kbd{?}, which displays a brief list of commands. When you are +finished looking at the list, make it go away by typing @key{SPC} +repeatedly. + +@format +>> Type a @key{?} now. Press @key{SPC} to see consecutive screenfuls of + the list until finished. Then type @key{SPC} several times. If + you are using Emacs, the help will then go away automatically. +@end format + + (If you are using the stand-alone Info reader, type @kbd{C-x 0} to +return here, that is---press and hold @key{CTRL}, type an @kbd{x}, +then release @key{CTRL} and @kbd{x}, and press @kbd{0}; that's a zero, +not the letter ``o''.) + + From now on, you will encounter large nodes without warning, and +will be expected to know how to use @key{SPC} and @key{BACKSPACE} to +move around in them without being told. Since not all terminals have +the same size screen, it would be impossible to warn you anyway. + +@format +>> Now type @kbd{n}, or click the middle mouse button on the @samp{Next} link, + to visit the next node. +@end format + +@node Help-Inv, Help-M, Help-^L, Getting Started +@comment node-name, next, previous, up +@section Invisible text in Emacs Info + + Before discussing menus, we need to make some remarks that are only +relevant to users reading Info using Emacs. Users of the stand-alone +version can skip this node by typing @kbd{]} now. + +@cindex invisible text in Emacs + In Emacs, certain text that appears in the stand-alone version is +normally hidden, technically because it has the @samp{invisibility} +property. Invisible text is really a part of the text. It becomes +visible (by default) after killing and yanking, it appears in printed +output, it gets saved to file just like any other text, and so on. +Thus it is useful to know it is there. + +@findex visible-mode +You can make invisible text visible by using the command @kbd{M-x +visible-mode}. Visible mode is a minor mode, so using the command a +second time will make the text invisible again. Watch the effects of +the command on the ``menu'' below and the top line of this node. + +If you prefer to @emph{always} see the invisible text, you can set +@code{Info-hide-note-references} to @code{nil}. Enabling Visible mode +permanently is not a real alternative, because Emacs Info also uses +(although less extensively) another text property that can change the +text being displayed, the @samp{display} property. Only the +invisibility property is affected by Visible mode. When, in this +tutorial, we refer to the @samp{Emacs} behavior, we mean the +@emph{default} Emacs behavior. + +Now type @kbd{]}, to learn about the @kbd{]} and @kbd{[} commands. + +@menu +* ]: Help-]. Node telling about ]. +* stuff: Help-]. Same node. +* Help-]:: Yet again, same node. +@end menu + +@node Help-], , , Help-Inv +@subsection The @kbd{]} and @kbd{[} commands + +If you type @kbd{n} now, you get an error message saying that this +node has no next node. Similarly, if you type @kbd{p}, the error +message tells you that there is no previous node. (The exact message +depends on the Info reader you use.) This is because @kbd{n} and +@kbd{p} carry you to the next and previous node @emph{at the same +level}. The present node is contained in a menu (see next) of the +node you came from, and hence is considered to be at a lower level. +It is the only node in the previous node's menu (even though it was +listed three times). Hence it has no next or previous node that +@kbd{n} or @kbd{p} could move to. + +If you systematically move through a manual by typing @kbd{n}, you run +the risk of skipping many nodes. You do not run this risk if you +systematically use @kbd{@key{SPC}}, because, when you scroll to the +bottom of a node and type another @kbd{@key{SPC}}, then this carries +you to the following node in the manual @emph{regardless of level}. +If you immediately want to go to that node, without having to scroll +to the bottom of the screen first, you can type @kbd{]}. + +Similarly, @kbd{@key{BACKSPACE}} carries you to the preceding node +regardless of level, after you scrolled to the beginning of the +present node. If you want to go to the preceding node immediately, +you can type @kbd{[}. + +For instance, typing this sequence will come back here in three steps: +@kbd{[ n [}. To do the same backward, type @kbd{] p ]}. + +Now type @kbd{]} to go to the next node and learn about menus. + +@node Help-M, Help-Xref, Help-Inv, Getting Started +@comment node-name, next, previous, up +@section Menus and the @kbd{m} command + +@cindex menus in an Info document +@cindex Info menus + With only the @kbd{n} (next), @kbd{p} (previous), @kbd{@key{SPC}}, +@kbd{@key{BACKSPACE}}, @kbd{]} and @kbd{[} commands for moving between +nodes, nodes are restricted to a linear sequence. Menus allow a +branching structure. A menu is a list of other nodes you can move to. +It is actually just part of the text of the node formatted specially +so that Info can interpret it. The beginning of a menu is always +identified by a line which starts with @w{@samp{* Menu:}}. A node +contains a menu if and only if it has a line in it which starts that +way. The only menu you can use at any moment is the one in the node +you are in. To use a menu in any other node, you must move to that +node first. + + After the start of the menu, each line that starts with a @samp{*} +identifies one subtopic. The line usually contains a brief name for +the subtopic (followed by a @samp{:}, normally hidden in Emacs), the +name of the node that talks about that subtopic (again, normally +hidden in Emacs), and optionally some further description of the +subtopic. Lines in the menu that do not start with a @samp{*} have no +special meaning---they are only for the human reader's benefit and do +not define additional subtopics. Here is an example: + +@example +* Foo: Node about FOO. This tells about FOO. +@end example + +The subtopic name is Foo, and the node describing it is @samp{Node +about FOO}. The rest of the line is just for the reader's +Information. [[ But this line is not a real menu item, simply because +there is no line above it which starts with @w{@samp{* Menu:}}. Also, +in a real menu item, the @samp{*} would appear at the very start of +the line. This is why the ``normally hidden'' text in Emacs, namely +@samp{: Node about FOO.}, is actually visible in this example, even +when Visible mode is off.]] + + When you use a menu to go to another node (in a way that will be +described soon), what you specify is the subtopic name, the first +thing in the menu line. Info uses it to find the menu line, extracts +the node name from it, and goes to that node. The reason that there +is both a subtopic name and a node name is that the node name must be +meaningful to the computer and may therefore have to be ugly looking. +The subtopic name can be chosen just to be convenient for the user to +specify. Often the node name is convenient for the user to specify +and so both it and the subtopic name are the same. There is an +abbreviation for this: + +@example +* Foo:: This tells about FOO. +@end example + +@noindent +This means that the subtopic name and node name are the same; they are +both @samp{Foo}. (The @samp{::} is normally hidden in Emacs.) + +@format +>> Now use @key{SPC} to find the menu in this node, then come back to + the front with a @kbd{b} and some @key{SPC}s. As you see, a menu is + actually visible in its node. If you cannot find a menu in a node + by looking at it, then the node does not have a menu and the + @kbd{m} command is not available. +@end format + +If you keep typing @key{SPC} once the menu appears on the screen, it +will move to another node (the first one in the menu). If that +happens, type @key{BACKSPACE} to come back. + +@kindex m @r{(Info mode)} + The command to go to one of the subnodes is @kbd{m}. This is very +different from the commands you have used: it is a command that +prompts you for more input. + + The Info commands you know do not need additional input; when you +type one of them, Info processes it instantly and then is ready for +another command. The @kbd{m} command is different: it needs to know +the @dfn{name of the subtopic}. Once you have typed @kbd{m}, Info +tries to read the subtopic name. + + Now, in the stand-alone Info, look for the line containing many +dashes near the bottom of the screen. (This is the stand-alone +equivalent for the mode line in Emacs.) There is one more line +beneath that one, but usually it is blank. (In Emacs, this is the +echo area.) When it is blank, Info is ready for a command, such as +@kbd{n} or @kbd{b} or @key{SPC} or @kbd{m}. If that line contains +text ending in a colon, it means Info is reading more input for the +last command. You can't type an Info command then, because Info is +trying to read input, not commands. You must either give the input +and finish the command you started, or type @kbd{Control-g} to cancel +the command. When you have done one of those things, the input entry +line becomes blank again. Then you can type Info commands again. + +@findex Info-menu + The command to go to a subnode via a menu is @kbd{m}. After you type +the @kbd{m}, the line at the bottom of the screen says @samp{Menu item: }. +You must then type the name of the subtopic you want, and end it with +a @key{RET}. + +@cindex abbreviating Info subnodes + You can abbreviate the subtopic name. If the abbreviation is not +unique, the first matching subtopic is chosen. Some menus put +the shortest possible abbreviation for each subtopic name in capital +letters, so you can see how much you need to type. It does not +matter whether you use upper case or lower case when you type the +subtopic. You should not put any spaces at the end, or inside of the +item name, except for one space where a space appears in the item in +the menu. + +@cindex completion of Info node names + You can also use the @dfn{completion} feature to help enter the +subtopic name. If you type the @key{TAB} key after entering part of a +name, it will fill in more of the name---as much as Info can deduce +from the part you have entered. + + If you move the cursor to one of the menu subtopic lines, then you do +not need to type the argument: you just type a @key{RET}, and it +stands for the subtopic of the line you are on. You can also click +the middle mouse button directly on the subtopic line to go there. + +Here is a menu to give you a chance to practice. This menu gives you +three ways of going to one place, Help-FOO: + +@menu +* Foo: Help-FOO. A node you can visit for fun. +* Bar: Help-FOO. We have made two ways to get to the same place. +* Help-FOO:: And yet another! +@end menu + +(Turn Visible mode on if you are using Emacs.) + +@format +>> Now type just an @kbd{m} and see what happens: +@end format + + Now you are ``inside'' an @kbd{m} command. Commands cannot be used +now; the next thing you will type must be the name of a subtopic. + + You can change your mind about doing the @kbd{m} by typing +@kbd{Control-g}. + +@format +>> Try that now; notice the bottom line clear. +@end format + +@format +>> Then type another @kbd{m}. +@end format + +@format +>> Now type @kbd{BAR}, the item name. Do not type @key{RET} yet. +@end format + + While you are typing the item name, you can use the @key{DEL} (or +@key{BACKSPACE}) key to cancel one character at a time if you make a +mistake. + +@format +>> Press @key{DEL} to cancel the @samp{R}. You could type another @kbd{R} + to replace it. But you do not have to, since @samp{BA} is a valid + abbreviation. +@end format + +@format +>> Now you are ready to go. Type a @key{RET}. +@end format + + After visiting @samp{Help-FOO}, you should return here. + + Another way to move to the menu subtopic lines and between them is +to type @key{TAB}. Each time you type a @key{TAB}, you move to the +next subtopic line. To move to a previous subtopic line in the +stand-alone reader, type @kbd{M-@key{TAB}}---that is, press and hold +the @key{META} key and then press @key{TAB}. (On some keyboards, the +@key{META} key might be labeled @samp{Alt}.) In Emacs Info, type +@kbd{S-@key{TAB}} to move to a previous subtopic line (press and hold +the @key{Shift} key and then press @key{TAB}). + + Once you move cursor to a subtopic line, press @key{RET} to go to +that subtopic's node. + +@cindex mouse support in Info mode +@kindex Mouse-2 @r{(Info mode)} + If your terminal supports a mouse, you have yet another way of going +to a subtopic. Move your mouse pointer to the subtopic line, +somewhere between the beginning @samp{*} and the colon @samp{:} which +ends the subtopic's brief name. You will see the subtopic's name +change its appearance (usually, its background color will change), and +the shape of the mouse pointer will change if your platform supports +that. After a while, if you leave the mouse on that spot, a small +window will pop up, saying ``Mouse-2: go to that node,'' or the same +message may appear at the bottom of the screen. + + @kbd{Mouse-2} is the second button of your mouse counting from the +left---the middle button on a 3-button mouse. (On a 2-button mouse, +you may have to press both buttons together to ``press the middle +button''.) The message tells you pressing @kbd{Mouse-2} with the +current position of the mouse pointer (on subtopic in the menu) will +go to that subtopic. + +@findex Info-mouse-follow-nearest-node + More generally, @kbd{Mouse-2} in an Info buffer finds the nearest +link to another node and goes there. For example, near a cross +reference it acts like @kbd{f}, in a menu it acts like @kbd{m}, on the +node's header line it acts like @kbd{n}, @kbd{p}, or @kbd{u}, etc. At +end of the node's text @kbd{Mouse-2} moves to the next node, or up if +there's no next node. + +@format +>> Type @kbd{n} to see more commands. +@end format + +@node Help-FOO, , , Help-M +@subsection The @kbd{u} command + + Congratulations! This is the node @samp{Help-FOO}. It has an @samp{Up} +pointer @samp{Help-M}, the node you just came from via the @kbd{m} +command. This is the usual convention---the nodes you reach from a menu +have @samp{Up} nodes that lead back to the menu. Menus move Down in the +tree, and @samp{Up} moves Up. @samp{Previous}, on the other hand, is +usually used to ``stay on the same level but go backwards''. + +@kindex u @r{(Info mode)} +@findex Info-up + You can go back to the node @samp{Help-M} by typing the command +@kbd{u} for ``Up''. This puts you at the menu subtopic line pointing +to the subnode that the @kbd{u} command brought you from. (Some Info +readers may put you at the @emph{front} of the node instead---to get +back to where you were reading, you have to type some @key{SPC}s.) + + Another way to go Up is to click @kbd{Mouse-2} on the @samp{Up} +pointer shown in the header line (provided that you have a mouse). + +@format +>> Now type @kbd{u} to move back up to @samp{Help-M}. +@end format + +@node Help-Xref, Help-Int, Help-M, Getting Started +@comment node-name, next, previous, up +@section Following Cross-References + +@cindex cross references in Info documents + In Info documentation, you will see many @dfn{cross references}. +Cross references look like this: @xref{Help-Cross, Cross}. That text +is a real, live cross reference, whose name is @samp{Cross} and which +points to the node named @samp{Help-Cross}. (The node name is hidden +in Emacs. Do @kbd{M-x visible-mode} to show or hide it.) + +@kindex f @r{(Info mode)} +@findex Info-follow-reference + You can follow a cross reference by moving the cursor to it and +press @key{RET}, just as in a menu. In Emacs, you can also click +@kbd{Mouse-1} on a cross reference to follow it; you can see that the +cross reference is mouse-sensitive by moving the mouse pointer to the +reference and watching how the underlying text and the mouse pointer +change in response. + + Another way to follow a cross reference is to type @kbd{f} and then +specify the name of the cross reference (in this case, @samp{Cross}) +as an argument. For this command, it does not matter where the cursor +was. If the cursor is on or near a cross reference, @kbd{f} suggests +that reference name in parentheses as the default; typing @key{RET} +will follow that reference. However, if you type a different +reference name, @kbd{f} will follow the other reference which has that +name. + +@format +>> Type @kbd{f}, followed by @kbd{Cross}, and then @key{RET}. +@end format + + As you enter the reference name, you can use the @key{DEL} (or +@key{BACKSPACE}) key to edit your input. If you change your mind +about following any reference, you can use @kbd{Control-g} to cancel +the command. Completion is available in the @kbd{f} command; you can +complete among all the cross reference names in the current node by +typing a @key{TAB}. + + To get a list of all the cross references in the current node, you +can type @kbd{?} after an @kbd{f}. The @kbd{f} continues to await a +cross reference name even after displaying the list, so if you don't +actually want to follow a reference, you should type a @kbd{Control-g} +to cancel the @kbd{f}. + +@format +>> Type @kbd{f?} to get a list of the cross references in this node. Then + type a @kbd{Control-g} and see how the @samp{f} gives up. +@end format + + The @key{TAB}, @kbd{M-@key{TAB}} and @kbd{S-@key{TAB}} keys, +which move between menu items in a menu, also move between cross +references outside of menus. + + Sometimes a cross reference (or a node) can lead to another file (in +other words another ``manual''), or, on occasion, even a file on a +remote machine (although Info files distributed with Emacs or the +stand-alone Info avoid using remote links). Such a cross reference +looks like this: @xref{Top,, Overview of Texinfo, texinfo, Texinfo: +The GNU Documentation Format}. (After following this link, type +@kbd{l} to get back to this node.) Here the name @samp{texinfo} +between parentheses refers to the file name. This file name appears +in cross references and node names if it differs from the current +file, so you can always know that you are going to be switching to +another manual and which one. + +However, Emacs normally hides some other text in cross-references. +If you put your mouse over the cross reference, then the information +appearing in a separate box (tool tip) or in the echo area will show +the full cross-reference including the file name and the node name of +the cross reference. If you have a mouse, just leave it over the +cross reference @xref{Top,, Overview of Texinfo, texinfo, Texinfo: +The GNU Documentation Format}, and watch what happens. If you +always like to have that information visible without having to move +your mouse over the cross reference, use @kbd{M-x visible-mode}, or +set @code{Info-hide-note-references} to a value other than @code{t} +(@pxref{Emacs Info Variables}). + +@format +>> Now type @kbd{n} to learn more commands. +@end format + +@node Help-Int, Help-Q, Help-Xref, Getting Started +@comment node-name, next, previous, up +@section Some intermediate Info commands + + The introductory course is almost over; please continue +a little longer to learn some intermediate-level commands. + + Most Info files have an index, which is actually a large node +containing little but a menu. The menu has one menu item for each +topic listed in the index. (As a special feature, menus for indices +may also include the line number within the node of the index entry. +This allows Info readers to go to the exact line of an entry, not just +the start of the containing node.) + + You can get to the index from the main menu of the file with the +@kbd{m} command and the name of the index node; then you can use the +@kbd{m} command again in the index node to go to the node that +describes the topic you want. + + There is also a short-cut Info command, @kbd{i}, which does all of +that for you. It searches the index for a given topic (a string) and +goes to the node which is listed in the index for that topic. +@xref{Search Index}, for a full explanation. + +@kindex l @r{(Info mode)} +@findex Info-history-back +@cindex going back in Info history + If you have been moving around to different nodes and wish to +retrace your steps, the @kbd{l} command (@kbd{l} for @dfn{last}) will +do that, one node-step at a time. As you move from node to node, Info +records the nodes where you have been in a special history list. The +@kbd{l} command revisits nodes in the history list; each successive +@kbd{l} command moves one step back through the history. + +@format +>> Try typing @kbd{p p n} and then three @kbd{l}'s, pausing in between +to see what each @kbd{l} does. You should wind up right back here. +@end format + + Note the difference between @kbd{l} and @kbd{p}: @kbd{l} moves to +where @emph{you} last were, whereas @kbd{p} always moves to the node +which the header says is the @samp{Previous} node (from this node, the +@samp{Prev} link leads to @samp{Help-Xref}). + +@kindex r @r{(Info mode)} +@findex Info-history-forward +@cindex going forward in Info history + You can use the @kbd{r} command (@code{Info-history-forward} in Emacs) +to revisit nodes in the history list in the forward direction, so that +@kbd{r} will return you to the node you came from by typing @kbd{l}. + +@kindex L @r{(Info mode)} +@findex Info-history +@cindex history list of visited nodes + The @kbd{L} command (@code{Info-history} in Emacs) creates a virtual +node that contains a list of all nodes you visited. You can select +a previously visited node from this menu to revisit it. + +@kindex d @r{(Info mode)} +@findex Info-directory +@cindex go to Directory node + The @kbd{d} command (@code{Info-directory} in Emacs) gets you +instantly to the Directory node. This node, which is the first one +you saw when you entered Info, has a menu which leads (directly or +indirectly, through other menus), to all the nodes that exist. The +Directory node lists all the manuals and other Info documents that +are, or could be, installed on your system. + +@format +>> Try doing a @kbd{d}, then do an @kbd{l} to return here (yes, + @emph{do} return). +@end format + +@kindex t @r{(Info mode)} +@findex Info-top-node +@cindex go to Top node + The @kbd{t} command moves to the @samp{Top} node of the manual. +This is useful if you want to browse the manual's main menu, or select +some specific top-level menu item. The Emacs command run by @kbd{t} +is @code{Info-top-node}. + +@format +>> Now type @kbd{n} to see the last node of the course. +@end format + + @xref{Advanced}, for more advanced Info features. + +@c If a menu appears at the end of this node, remove it. +@c It is an accident of the menu updating command. + +@node Help-Q, , Help-Int, Getting Started +@comment node-name, next, previous, up +@section Quitting Info + +@kindex q @r{(Info mode)} +@findex Info-exit +@cindex quitting Info mode + To get out of Info, back to what you were doing before, type @kbd{q} +for @dfn{Quit}. This runs @code{Info-exit} in Emacs. + + This is the end of the basic course on using Info. You have learned +how to move in an Info document, and how to follow menus and cross +references. This makes you ready for reading manuals top to bottom, +as new users should do when they learn a new package. + + Another set of Info commands is useful when you need to find +something quickly in a manual---that is, when you need to use a manual +as a reference rather than as a tutorial. We urge you to learn +these search commands as well. If you want to do that now, follow this +cross reference to @ref{Advanced}. + +Yet another set of commands are meant for experienced users; you can +find them by looking in the Directory node for documentation on Info. +Finding them will be a good exercise in using Info in the usual +manner. + +@format +>> Type @kbd{d} to go to the Info directory node; then type + @kbd{mInfo} and Return, to get to the node about Info and + see what other help is available. +@end format + + +@node Advanced +@chapter Advanced Info Commands + + This chapter describes various advanced Info commands. (If you +are using a stand-alone Info reader, there are additional commands +specific to it, which are documented in several chapters of @ref{Top,, +GNU Info, info-stnd, GNU Info}.) + +@kindex C-q @r{(Info mode)} + One advanced command useful with most of the others described here +is @kbd{C-q}, which ``quotes'' the next character so that it is +entered literally (@pxref{Inserting Text,,,emacs,The GNU Emacs +Manual}). For example, pressing @kbd{?} ordinarily brings up a list +of completion possibilities. If you want to (for example) search for +an actual @samp{?} character, the simplest way is to insert it using +@kbd{C-q ?}. This works the same in Emacs and stand-alone Info. + +@menu +* Search Text:: How to search Info documents. +* Search Index:: How to search the indices for specific subjects. +* Go to node:: How to go to a node by name. +* Choose menu subtopic:: How to choose a menu subtopic by its number. +* Create Info buffer:: How to create a new Info buffer in Emacs. +* Emacs Info Variables:: Variables modifying the behavior of Emacs Info. +@end menu + + +@node Search Text, Search Index, , Advanced +@comment node-name, next, previous, up +@section @kbd{s} searches Info documents + +@cindex searching Info documents +@cindex Info document as a reference + The commands which move between and inside nodes allow you to read +the entire manual or its large portions. But what if you need to find +some information in the manual as fast as you can, and you don't know +or don't remember in what node to look for it? This need arises when +you use a manual as a @dfn{reference}, or when it is impractical to +read the entire manual before you start using the programs it +describes. + + Info has powerful searching facilities that let you find things +quickly. You can search either the manual text or its indices. + +@kindex s @r{(Info mode)} +@findex Info-search + The @kbd{s} command allows you to search a whole Info file for a string. +It switches to the next node if and when that is necessary. You +type @kbd{s} followed by the string to search for, terminated by +@key{RET}. To search for the same string again, just @kbd{s} followed +by @key{RET} will do. The file's nodes are scanned in the order +they are in the file, which has no necessary relationship to the +order that they may be in the tree structure of menus and @samp{next} +pointers. But normally the two orders are not very different. In any +case, you can always look at the mode line to find out what node you have +reached, if the header is not visible (this can happen, because @kbd{s} +puts your cursor at the occurrence of the string, not at the beginning +of the node). + +@kindex M-s @r{(Info mode)} + In Emacs, @kbd{Meta-s} is equivalent to @kbd{s}. That is for +compatibility with other GNU packages that use @kbd{M-s} for a similar +kind of search command. Both @kbd{s} and @kbd{M-s} run in Emacs the +command @code{Info-search}. + +@kindex C-s @r{(Info mode)} +@kindex C-r @r{(Info mode)} +@findex isearch + Instead of using @kbd{s} in Emacs Info and in the stand-alone Info, +you can use an incremental search started with @kbd{C-s} or @kbd{C-r}. +It can search through multiple Info nodes. @xref{Incremental Search,,, +emacs, The GNU Emacs Manual}. In Emacs, you can disable this behavior +by setting the variable @code{Info-isearch-search} to @code{nil} +(@pxref{Emacs Info Variables}). + +@node Search Index, Go to node, Search Text, Advanced +@comment node-name, next, previous, up +@section @kbd{i} searches the indices for specific subjects + +@cindex searching Info indices +@kindex i @r{(Info mode)} +@findex Info-index + Since most topics in the manual should be indexed, you should try +the index search first before the text search. The @kbd{i} command +prompts you for a subject and then looks up that subject in the +indices. If it finds an index entry with the subject you typed, it +goes to the node to which that index entry points. You should browse +through that node to see whether the issue you are looking for is +described there. If it isn't, type @kbd{,} one or more times to go +through additional index entries which match your subject. + + The @kbd{i} command and subsequent @kbd{,} commands find all index +entries which include the string you typed @emph{as a substring}. +For each match, Info shows in the echo area the full index entry it +found. Often, the text of the full index entry already gives you +enough information to decide whether it is relevant to what you are +looking for, so we recommend that you read what Info shows in the echo +area before looking at the node it displays. + + Since @kbd{i} looks for a substring, you can search for subjects even +if you are not sure how they are spelled in the index. For example, +suppose you want to find something that is pertinent to commands which +complete partial input (e.g., when you type @key{TAB}). If you want +to catch index entries that refer to ``complete,'' ``completion,'' and +``completing,'' you could type @kbd{icomplet@key{RET}}. + + Info documents which describe programs should index the commands, +options, and key sequences that the program provides. If you are +looking for a description of a command, an option, or a key, just type +their names when @kbd{i} prompts you for a topic. For example, if you +want to read the description of what the @kbd{C-l} key does, type +@kbd{iC-l@key{RET}} literally. + +@findex info-apropos +@findex index-apropos +If you aren't sure which manual documents the topic you are looking +for, try the @kbd{M-x info-apropos} command in Emacs, or the @kbd{M-x +index-apropos} command in the stand-alone reader. It prompts for +a string and then looks up that string in all the indices of all the +Info documents installed on your system. + +@node Go to node, Choose menu subtopic, Search Index, Advanced +@comment node-name, next, previous, up +@section @kbd{g} goes to a node by name + +@kindex g @r{(Info mode)} +@findex Info-goto-node +@cindex go to a node by name + If you know a node's name, you can go there by typing @kbd{g}, the +name, and @key{RET}. Thus, @kbd{gTop@key{RET}} would go to the node +called @samp{Top} in this file. (This is equivalent to @kbd{t}, see +@ref{Help-Int}.) @kbd{gGo to node@key{RET}} would come back here. + + Unlike @kbd{m}, @kbd{g} does not allow the use of abbreviations. +But it does allow completion, so you can type @key{TAB} to complete a +partial node name. + +@cindex go to another Info file + To go to a node in another file, you can include the file name in the +node name by putting it at the front, in parentheses. Thus, +@kbd{g(dir)Top@key{RET}} would go to the Info Directory node, which is +the node @samp{Top} in the Info file @file{dir}. Likewise, +@kbd{g(emacs)Top@key{RET}} goes to the top node of the Emacs manual. + + The node name @samp{*} specifies the whole file. So you can look at +all of the current file by typing @kbd{g*@key{RET}} or all of any +other file with @kbd{g(@var{filename})*@key{RET}}. + +@node Choose menu subtopic, Create Info buffer, Go to node, Advanced +@comment node-name, next, previous, up +@section @kbd{1}--@kbd{9} choose a menu subtopic by its number + +@kindex 1 @r{through} 9 @r{(Info mode)} +@findex Info-nth-menu-item +@cindex select @var{n}'th menu item + If you begrudge each character of type-in which your system requires, +you might like to use the commands @kbd{1}, @kbd{2}, @kbd{3}, @kbd{4}, +@dots{}, @kbd{9}. They are short for the @kbd{m} command together +with a name of a menu subtopic. @kbd{1} goes through the first item +in the current node's menu; @kbd{2} goes through the second item, etc. +In the stand-alone reader, @kbd{0} goes through the last menu item; +this is so you need not count how many entries are there. + + If your display supports multiple fonts, colors or underlining, and +you are using Emacs' Info mode to read Info files, the third, sixth +and ninth menu items have a @samp{*} that stands out, either in color +or in some other attribute, such as underline; this makes it easy to +see at a glance which number to use for an item. + + Some terminals don't support either multiple fonts, colors or +underlining. If you need to actually count items, it is better to use +@kbd{m} instead, and specify the name, or use @key{TAB} to quickly +move between menu items. + +@node Create Info buffer, Emacs Info Variables, Choose menu subtopic, Advanced +@comment node-name, next, previous, up +@section @kbd{M-n} creates a new independent Info buffer in Emacs + +@kindex M-n @r{(Info mode)} +@findex clone-buffer +@cindex multiple Info buffers + If you are reading Info in Emacs, you can select a new independent +Info buffer in a new Emacs window by typing @kbd{M-n}. The new buffer +starts out as an exact copy of the old one, but you will be able to +move independently between nodes in the two buffers. (In Info mode, +@kbd{M-n} runs the Emacs command @code{clone-buffer}.) + + In Emacs Info, you can also produce new Info buffers by giving a +numeric prefix argument to the @kbd{m} and @kbd{g} commands. @kbd{C-u +m} and @kbd{C-u g} go to a new node in exactly the same way that +@kbd{m} and @kbd{g} do, but they do so in a new Info buffer which they +select in another window. + + Another way to produce new Info buffers in Emacs is to use a numeric +prefix argument for the @kbd{C-h i} command (@code{info}) which +switches to the Info buffer with that number. Thus, @kbd{C-u 2 C-h i} +switches to the buffer @samp{*info*<2>}, creating it if necessary. + +@node Emacs Info Variables, , Create Info buffer, Advanced +@comment node-name, next, previous, up +@section Emacs Info-mode Variables + +The following variables may modify the behavior of Info-mode in Emacs; +you may wish to set one or several of these variables interactively, +or in your init file. @xref{Examining, Examining and Setting +Variables, Examining and Setting Variables, emacs, The GNU Emacs +Manual}. The stand-alone Info reader program has its own set of +variables, described in @ref{Variables,, Manipulating Variables, +info-stnd, GNU Info}. + +@vtable @code +@item Info-directory-list +The list of directories to search for Info files. Each element is a +string (directory name) or @code{nil} (try default directory). If not +initialized Info uses the environment variable @env{INFOPATH} to +initialize it, or @code{Info-default-directory-list} if there is no +@env{INFOPATH} variable in the environment. + +If you wish to customize the Info directory search list for both Emacs +Info and stand-alone Info, it is best to set the @env{INFOPATH} +environment variable, since that applies to both programs. + +@item Info-additional-directory-list +A list of additional directories to search for Info documentation files. +These directories are not searched for merging the @file{dir} file. + +@item Info-mode-hook +Hooks run when @code{Info-mode} is called. By default, it contains +the hook @code{turn-on-font-lock} which enables highlighting of Info +files. You can change how the highlighting looks by customizing the +faces @code{info-node}, @code{info-xref}, @code{info-xref-visited}, +@code{info-header-xref}, @code{info-header-node}, @code{info-menu-header}, +@code{info-menu-star}, and @code{info-title-@var{n}} (where @var{n} +is the level of the section, a number between 1 and 4). To customize +a face, type @kbd{M-x customize-face @key{RET} @var{face} @key{RET}}, +where @var{face} is one of the face names listed here. + +@item Info-fontify-maximum-menu-size +Maximum size of menu to fontify if @code{font-lock-mode} is non-@code{nil}. + +@item Info-fontify-visited-nodes +If non-@code{nil}, menu items and cross-references pointing to visited +nodes are displayed in the @code{info-xref-visited} face. + +@item Info-use-header-line +If non-@code{nil}, Emacs puts in the Info buffer a header line showing +the @samp{Next}, @samp{Prev}, and @samp{Up} links. A header line does +not scroll with the rest of the buffer, making these links always +visible. + +@item Info-hide-note-references +As explained in earlier nodes, the Emacs version of Info normally +hides some text in menus and cross-references. You can completely +disable this feature, by setting this option to @code{nil}. Setting +it to a value that is neither @code{nil} nor @code{t} produces an +intermediate behavior, hiding a limited amount of text, but showing +all text that could potentially be useful. + +@item Info-scroll-prefer-subnodes +If set to a non-@code{nil} value, @key{SPC} and @key{BACKSPACE} (or +@key{DEL}) keys in a menu visit subnodes of the current node before +scrolling to its end or beginning, respectively. For example, if the +node's menu appears on the screen, the next @key{SPC} moves to a +subnode indicated by the following menu item. Setting this option to +@code{nil} results in behavior similar to the stand-alone Info reader +program, which visits the first subnode from the menu only when you +hit the end of the current node. The default is @code{nil}. + +@item Info-isearch-search +If non-@code{nil}, isearch in Info searches through multiple nodes. + +@item Info-enable-active-nodes +When set to a non-@code{nil} value, allows Info to execute Lisp code +associated with nodes. The Lisp code is executed when the node is +selected. The Lisp code to be executed should follow the node +delimiter (the @samp{DEL} character) and an @samp{execute: } tag, like +this: + +@example +^_execute: (message "This is an active node!") +@end example +@end vtable + + +@node Expert Info +@chapter Info for Experts + + This chapter explains how to write an Info file by hand. However, +in most cases, writing a Texinfo file is better, since you can use it +to make a printed manual or produce other formats, such as HTML and +DocBook, as well as for generating Info files. + +The @code{makeinfo} command converts a Texinfo file into an Info file; +@code{texinfo-format-region} and @code{texinfo-format-buffer} are GNU +Emacs functions that do the same. + +@xref{Top,, Overview of Texinfo, texinfo, Texinfo: The GNU +Documentation Format}, for how to write a Texinfo file. + +@xref{Creating an Info File,,, texinfo, Texinfo: The GNU Documentation +Format}, for how to create an Info file from a Texinfo file. + +@xref{Installing an Info File,,, texinfo, Texinfo: The GNU +Documentation Format}, for how to install an Info file after you +have created one. + +However, if you want to edit an Info file manually and install it manually, +here is how. + +@menu +* Add:: Describes how to add new nodes to the hierarchy. + Also tells what nodes look like. +* Menus:: How to add to or create menus in Info nodes. +* Cross-refs:: How to add cross-references to Info nodes. +* Tags:: How to make tags tables for Info files. +* Checking:: Checking an Info File. +@end menu + +@node Add, Menus, , Expert Info +@comment node-name, next, previous, up +@section Adding a new node to Info + +To add a new topic to the list in the Info directory, you must: + +@enumerate +@item +Create some nodes, in some file, to document that topic. +@item +Put that topic in the menu in the directory. @xref{Menus, Menu}. +@end enumerate + +@cindex node delimiters + The new node can live in an existing documentation file, or in a new +one. It must have a @samp{^_} character before it (invisible to the +user; this node has one but you cannot see it), and it ends with either +a @samp{^_}, a @samp{^L} (``formfeed''), or the end of file.@footnote{If +you put in a @samp{^L} to end a new node, be sure that there is a +@samp{^_} after it to start the next one, since @samp{^L} cannot +@emph{start} a node. Also, a nicer way to make a node boundary be a +page boundary as well is to put a @samp{^L} @emph{right after} the +@samp{^_}.} + + The @samp{^_} starting a node must be followed by a newline or a +@samp{^L} newline, after which comes the node's header line. The +header line must give the node's name (by which Info finds it), and +state the names of the @samp{Next}, @samp{Previous}, and @samp{Up} +nodes (if there are any). As you can see, this node's @samp{Up} node +is the node @samp{Expert Info}. The @samp{Next} node is @samp{Menus}. + +@cindex node header line format +@cindex format of node headers + The keywords @dfn{Node}, @dfn{Next}, @dfn{Previous}, and @dfn{Up} +may appear in any order, anywhere in the header line, but the +recommended order is the one in this sentence. Each keyword must be +followed by a colon, spaces and tabs, and then the appropriate name. +The name may be terminated with a tab, a comma, or a newline. A space +does not end it; node names may contain spaces. The case of letters +in the names is insignificant. + +@cindex node name format +@cindex Directory node + A node name has two forms. A node in the current file is named by +what appears after the @samp{Node: } in that node's first line. For +example, this node's name is @samp{Add}. A node in another file is +named by @samp{(@var{filename})@var{node-within-file}}, as in +@samp{(info)Add} for this node. If the file name starts with @samp{./}, +then it is relative to the current directory; otherwise, it is +relative starting from the standard directory for Info files of your +site. The name @samp{(@var{filename})Top} can be abbreviated to just +@samp{(@var{filename})}. By convention, the name @samp{Top} is used +for the ``highest'' node in any single file---the node whose @samp{Up} +points out of the file. The @samp{Directory} node is @file{(dir)}, it +points to a file @file{dir} which holds a large menu listing all the +Info documents installed on your site. The @samp{Top} node of a +document file listed in the @samp{Directory} should have an @samp{Up: +(dir)} in it. + +@cindex unstructured documents + The node name @kbd{*} is special: it refers to the entire file. +Thus, @kbd{g*} shows you the whole current file. The use of the +node @kbd{*} is to make it possible to make old-fashioned, +unstructured files into nodes of the tree. + + The @samp{Node:} name, in which a node states its own name, must not +contain a file name, since when Info searches for a node, it does not +expect a file name to be there. The @samp{Next}, @samp{Previous} and +@samp{Up} names may contain them. In this node, since the @samp{Up} +node is in the same file, it was not necessary to use one. + + Note that the nodes in this file have a file name in the header +line. The file names are ignored by Info, but they serve as comments +to help identify the node for the user. + +@node Menus, Cross-refs, Add, Expert Info +@comment node-name, next, previous, up +@section How to Create Menus + + Any node in the Info hierarchy may have a @dfn{menu}---a list of subnodes. +The @kbd{m} command searches the current node's menu for the topic which it +reads from the terminal. + +@cindex menu and menu entry format + A menu begins with a line starting with @w{@samp{* Menu:}}. The +rest of the line is a comment. After the starting line, every line +that begins with a @samp{* } lists a single topic. The name of the +topic---what the user must type at the @kbd{m}'s command prompt to +select this topic---comes right after the star and space, and is +followed by a colon, spaces and tabs, and the name of the node which +discusses that topic. The node name, like node names following +@samp{Next}, @samp{Previous} and @samp{Up}, may be terminated with a +tab, comma, or newline; it may also be terminated with a period. + + If the node name and topic name are the same, then rather than +giving the name twice, the abbreviation @samp{* @var{name}::} may be +used (and should be used, whenever possible, as it reduces the visual +clutter in the menu). + + It is considerate to choose the topic names so that they differ +from each other very near the beginning---this allows the user to type +short abbreviations. In a long menu, it is a good idea to capitalize +the beginning of each item name which is the minimum acceptable +abbreviation for it (a long menu is more than 5 or so entries). + + The nodes listed in a node's menu are called its ``subnodes,'' and it +is their ``superior''. They should each have an @samp{Up:} pointing at +the superior. It is often useful to arrange all or most of the subnodes +in a sequence of @samp{Next} and @samp{Previous} pointers so that +someone who wants to see them all need not keep revisiting the Menu. + + The Info Directory is simply the menu of the node @samp{(dir)Top}---that +is, node @samp{Top} in file @file{.../info/dir}. You can put new entries +in that menu just like any other menu. The Info Directory is @emph{not} the +same as the file directory called @file{info}. It happens that many of +Info's files live in that file directory, but they do not have to; and +files in that directory are not automatically listed in the Info +Directory node. + + Also, although the Info node graph is claimed to be a ``hierarchy,'' +in fact it can be @emph{any} directed graph. Shared structures and +pointer cycles are perfectly possible, and can be used if they are +appropriate to the meaning to be expressed. There is no need for all +the nodes in a file to form a connected structure. In fact, this file +has two connected components. You are in one of them, which is under +the node @samp{Top}; the other contains the node @samp{Help} which the +@kbd{h} command goes to. In fact, since there is no garbage +collector on the node graph, nothing terrible happens if a substructure +is not pointed to, but such a substructure is rather useless since nobody +can ever find out that it exists. + +@node Cross-refs, Tags, Menus, Expert Info +@comment node-name, next, previous, up +@section Creating Cross References + +@cindex cross reference format + A cross reference can be placed anywhere in the text, unlike a menu +item which must go at the front of a line. A cross reference looks +like a menu item except that it has @samp{*note} instead of @samp{*}. +It @emph{cannot} be terminated by a @samp{)}, because @samp{)}'s are +so often part of node names. If you wish to enclose a cross reference +in parentheses, terminate it with a period first. Here are two +examples of cross references pointers: + +@example +*Note details: commands. (See *note 3: Full Proof.) +@end example + +@noindent +@emph{These are just examples.} The places they ``lead to'' do not +really exist! + +@menu +* Help-Cross:: Target of a cross-reference. +@end menu + + +@node Help-Cross, , , Cross-refs +@subsection The node reached by the cross reference in Info + + This is the node reached by the cross reference named @samp{Cross}. + + While this node is specifically intended to be reached by a cross +reference, most cross references lead to nodes that ``belong'' +someplace else far away in the structure of an Info document. So you +cannot expect this node to have a @samp{Next}, @samp{Previous} or +@samp{Up} links pointing back to where you came from. In general, the +@kbd{l} (el) command is the only way to get back there. + +@format +>> Type @kbd{l} to return to the node where the cross reference was. +@end format + +@node Tags, Checking, Cross-refs, Expert Info +@comment node-name, next, previous, up +@section Tags Tables for Info Files + +@cindex tags tables in Info files + You can speed up the access to nodes of a large Info file by giving +it a tags table. Unlike the tags table for a program, the tags table for +an Info file lives inside the file itself and is used +automatically whenever Info reads in the file. + +@findex Info-tagify + To make a tags table, go to a node in the file using Emacs Info mode and type +@kbd{M-x Info-tagify}. Then you must use @kbd{C-x C-s} to save the +file. Info files produced by the @code{makeinfo} command that is part +of the Texinfo package always have tags tables to begin with. + +@cindex stale tags tables +@cindex update Info tags table + Once the Info file has a tags table, you must make certain it is up +to date. If you edit an Info file directly (as opposed to editing its +Texinfo source), and, as a result of deletion of text, any node moves back +more than a thousand characters in the file from the position +recorded in the tags table, Info will no longer be able to find that +node. To update the tags table, use the @code{Info-tagify} command +again. + + An Info file tags table appears at the end of the file and looks like +this: + +@example +^_^L +Tag Table: +File: info, Node: Cross-refs^?21419 +File: info, Node: Tags^?22145 +^_ +End Tag Table +@end example + +@noindent +Note that it contains one line per node, and this line contains +the beginning of the node's header (ending just after the node name), +a @samp{DEL} character, and the character position in the file of the +beginning of the node. + +@node Checking, , Tags, Expert Info +@section Checking an Info File + +When creating an Info file, it is easy to forget the name of a node when +you are making a pointer to it from another node. If you put in the +wrong name for a node, this is not detected until someone tries to go +through the pointer using Info. Verification of the Info file is an +automatic process which checks all pointers to nodes and reports any +pointers which are invalid. Every @samp{Next}, @samp{Previous}, and +@samp{Up} is checked, as is every menu item and every cross reference. In +addition, any @samp{Next} which does not have a @samp{Previous} pointing +back is reported. Only pointers within the file are checked, because +checking pointers to other files would be terribly slow. But those are +usually few. + +@findex Info-validate +To check an Info file, do @kbd{M-x Info-validate} while looking at any +node of the file with Emacs Info mode. + +@node Index +@unnumbered Index + +This is an alphabetical listing of all the commands, variables, and +topics discussed in this document. + +@printindex cp + +@bye + +@ignore + arch-tag: 965c1638-01d6-4156-9227-b10418b9d8e8 +@end ignore |