@c This is part of the Emacs manual.
-@c Copyright (C) 1985, 86, 87, 93, 94, 95, 97, 2000, 2001, 2004
-@c Free Software Foundation, Inc.
+@c Copyright (C) 1985, 1986, 1987, 1993, 1994, 1995, 1997, 2000, 2001,
+@c 2002, 2003, 2004, 2005, 2006 Free Software Foundation, Inc.
@c See file emacs.texi for copying conditions.
@node Help, Mark, M-x, Top
@chapter Help
@kindex F1
Emacs provides extensive help features accessible through a single
-character, @kbd{C-h}. @kbd{C-h} is a prefix key that is used for
-commands that display documentation. The characters that you can type after
-@kbd{C-h} are called @dfn{help options}. One help option is @kbd{C-h};
-that is how you ask for help about using @kbd{C-h}. To cancel, type
-@kbd{C-g}. The function key @key{F1} is equivalent to @kbd{C-h}.
+character, @kbd{C-h} (or @key{F1}). @kbd{C-h} is a prefix key that is
+used for commands that display documentation. The characters that you
+can type after @kbd{C-h} are called @dfn{help options}. One help
+option is @kbd{C-h}; that is how you ask for help about using
+@kbd{C-h}. To cancel, type @kbd{C-g}. The function key @key{F1} is
+equivalent to @kbd{C-h}.
@kindex C-h C-h
@findex help-for-help
@kbd{C-h C-h} (@code{help-for-help}) displays a list of the possible
-help options, each with a brief description. Before you type a help
-option, you can use @key{SPC} or @key{DEL} to scroll through the list.
+help options, each with a brief description. You can look at the
+list, using @key{SPC} and @key{DEL} to scroll through it, then type
+the help option you want. To cancel, type @kbd{C-g}.
@kbd{C-h} or @key{F1} means ``help'' in various other contexts as
well. After a prefix key, it displays a list of the alternatives that
Most help buffers use a special major mode, Help mode, which lets you
scroll conveniently with @key{SPC} and @key{DEL}. It also offers
-hyperlinks to further help regarding cross-referenced names, Info nodes,
-customization buffers and the like. @xref{Help Mode}.
+hyperlinks to URLs and further help regarding cross-referenced names, Info
+nodes, customization buffers and the like. @xref{Help Mode}.
@cindex searching documentation efficiently
@cindex looking for a subject in documentation
manual index, then finally look in the FAQ and the package keywords.
@table @kbd
-@item C-h a @var{topic} @key{RET}
-This searches for commands whose names match @var{topic}, which should
-be a regular expression (@pxref{Regexps}). Browse the buffer that this
-command displays to find what you are looking for. @xref{Apropos}.
-
-@item M-x apropos @key{RET} @var{topic} @key{RET}
-This works like @kbd{C-h a}, but it also searches for noninteractive
-functions and for variables. @xref{Apropos}.
-
-@item M-x apropos-documentation @key{RET} @var{topic} @key{RET}
-This searches the @emph{documentation strings} (the built-in short
-descriptions) of all variables and functions (not their names) for a
-match for @var{topic}, a regular expression. @xref{Apropos}.
+@item C-h a @var{topics} @key{RET}
+This searches for commands whose names match @var{topics}, which
+should be a keyword, a list of keywords, or a regular expression
+(@pxref{Regexps}). This command displays all the matches in a new
+buffer. @xref{Apropos}.
@item C-h i d m emacs @key{RET} i @var{topic} @key{RET}
This looks up @var{topic} in the indices of the Emacs on-line manual.
pertinent to the feature you need. @xref{Library Keywords}.
@end table
- To find the documentation of a key sequence or a menu item, type
-@kbd{C-h K} and then type that key sequence or select the menu
-item. This looks up the description of the command invoked by the key
-or the menu in the appropriate manual (not necessarily the Emacs
-manual). Likewise, use @kbd{C-h F} for reading documentation of a
-command.
-
@menu
* Help Summary:: Brief list of all Help commands.
* Key Help:: Asking what a key does in Emacs.
Here is a summary of the Emacs interactive help commands.
@xref{Help Files}, for other help commands that just display a
-pre-written file of information.
+pre-written file of information. The character that follows
+@kbd{C-h} is a ``help option.''
@table @kbd
-@item C-h a @var{regexp} @key{RET}
-Display a list of commands whose names match @var{regexp}
-(@code{apropos-command}).
+@item C-h a @var{topics} @key{RET}
+Display a list of commands whose names match @var{topics}
+(@code{apropos-command}; @pxref{Apropos}).
@item C-h b
Display a table of all key bindings in effect now, in this order: minor
mode bindings, major mode bindings, and global bindings
Show the name of the command that @var{key} runs
(@code{describe-key-briefly}). Here @kbd{c} stands for ``character.''
For more extensive information on @var{key}, use @kbd{C-h k}.
+@item C-h d @var{topics} @key{RET}
+Display a list of commands and variables whose documentation matches
+@var{topics} (@code{apropos-documentation}).
+@item C-h e
+Display the @code{*Messages*} buffer
+(@code{view-echo-area-messages}).
@item C-h f @var{function} @key{RET}
Display documentation on the Lisp function named @var{function}
(@code{describe-function}). Since commands are Lisp functions,
programming language you are editing (@code{info-lookup-symbol}).
@item C-h .
Display a help message associated with special text areas, such as
-links (@code{display-local-help}).
+links in @samp{*Help*} buffers (@code{display-local-help}).
@end table
@node Key Help
@kindex C-h c
@findex describe-key-briefly
- The most basic @kbd{C-h} options are @kbd{C-h c}
+ The most basic @kbd{C-h} commands are @kbd{C-h c}
(@code{describe-key-briefly}) and @w{@kbd{C-h k}} (@code{describe-key}).
@kbd{C-h c @var{key}} displays in the echo area the name of the command
that @var{key} is bound to. For example, @kbd{C-h c C-f} displays
displays the documentation string of the command as well as its name.
This is too big for the echo area, so a window is used for the display.
- @kbd{C-h c} and @kbd{C-h k} work for any sort of key sequences,
-including function keys and mouse events.
+@kindex C-h K
+@findex Info-goto-emacs-key-command-node
+ To find the documentation of a key sequence, type @kbd{C-h K} and
+then enter that key sequence. This looks up the description of the
+command invoked by the key in whichever manual describes it (this need
+not be the Emacs manual). @kbd{C-h K} runs the command
+@code{Info-goto-emacs-key-command-node}.
+
+ @kbd{C-h c}, @kbd{C-h k} and @kbd{C-h K} work for any sort of key
+sequences, including function keys, menus, and mouse events. For
+instance, you can type @kbd{C-h k} and then select a menu item from
+the menu bar, to show the documentation string of the command that
+menu item runs.
@kindex C-h w
@findex where-is
hyperlinks to the definition, if you have the source files installed.
(@xref{Hyperlinking}.) If you know Lisp (or C), this provides the
ultimate documentation. If you don't know Lisp, you should learn it.
-If you are just @emph{using} Emacs, treating Emacs as an object
-(file), then you don't really love it. For true intimacy with your
-editor, you need to read the source code.
+(The Introduction to Emacs Lisp Programming, available from the FSF
+through fsf.org, is a good way to get started.) Emacs won't be happy
+if it feels you are just @emph{using} Emacs, treating it as an object
+program. If you really love Emacs, show that you care by reading the
+source code.
+
+@kindex C-h F
+@findex Info-goto-emacs-command-node
+ To find a specific function's documentation in a manual, use
+@kbd{C-h F} (@code{Info-goto-emacs-command-node}). This knows
+about various manuals, not just the Emacs manual, and finds the
+right one.
@node Apropos
@section Apropos
+ A more sophisticated sort of question to ask is, ``What are the
+commands for working with files?'' The @dfn{apropos} commands ask
+such questions---they look for things whose names match an
+@dfn{apropos pattern}, which means either a word, a list of words, or
+a regular expression. Each apropos command displays a list of
+matching items in a special buffer.
+
+@table @kbd
+@item C-h a @var{pattern} @key{RET}
+Search for commands whose names match @var{pattern}.
+
+@item M-x apropos @key{RET} @var{pattern} @key{RET}
+Similar, but it searches for noninteractive functions and for
+variables, as well as commands.
+
+@item M-x apropos-variable @key{RET} @var{pattern} @key{RET}
+Similar, but it searches for variables only.
+
+@item M-x apropos-value @key{RET} @var{pattern} @key{RET}
+Similar, but it searches for variables based on their values, or
+functions based on their definitions.
+
+@item C-h d @var{pattern} @key{RET}
+Search the @emph{documentation strings} (the built-in short
+descriptions) of all variables and functions (not their names) for a
+match for @var{pattern}.
+@end table
+
@kindex C-h a
@findex apropos-command
@cindex apropos
- A more sophisticated sort of question to ask is, ``What are the
-commands for working with files?'' To ask this question, type @kbd{C-h
-a file @key{RET}}, which displays a list of all command names that
-contain @samp{file}, including @code{copy-file}, @code{find-file}, and
-so on. With each command name appears a brief description of how to use
-the command, and what keys you can currently invoke it with. For
-example, it would say that you can invoke @code{find-file} by typing
-@kbd{C-x C-f}. The @kbd{a} in @kbd{C-h a} stands for ``Apropos'';
-@kbd{C-h a} runs the command @code{apropos-command}. This command
-normally checks only commands (interactive functions); if you specify a
-prefix argument, it checks noninteractive functions as well.
-
- Because @kbd{C-h a} looks only for commands matching the string you
-specify, you may not find what you want on the first try. In that
-case, don't just give up. You can give Apropos a list of words to
-search for. When more than one word is specified, at least two of
-those words must be present for an item to match. If you are looking
-for commands to kill a chunk of text before point, try @kbd{C-h a kill
-back behind before @key{RET}}. For even greater flexibility, you can
-also supply a regular expression to Apropos (@pxref{Regexps}).
+ To find the commands that work on files, type @kbd{C-h a file
+@key{RET}}. This displays a list of all command names that contain
+@samp{file}, including @code{copy-file}, @code{find-file}, and so on.
+With each command name appears a brief description of how to use the
+command, and what keys you can currently invoke it with. For example,
+it would say that you can invoke @code{find-file} by typing @kbd{C-x
+C-f}. The @kbd{a} in @kbd{C-h a} stands for ``Apropos''; @kbd{C-h a}
+runs the command @code{apropos-command}. This command normally checks
+only commands (interactive functions); if you specify a prefix
+argument, it checks noninteractive functions as well.
+
+ If you want more information about a function definition, variable or
+symbol property listed in the Apropos buffer, you can click on it with
+@kbd{Mouse-1} or @kbd{Mouse-2}, or move there and type @key{RET}.
+
+ @kbd{C-h a} with a single word can find too many matches. Don't
+just give up; you can give Apropos a list of words to search for.
+When you specify more than one word in the apropos pattern, a name
+must contain at least two of the words in order to match. Thus, if
+you are looking for commands to kill a chunk of text before point, you
+could try @kbd{C-h a kill back backward behind before @key{RET}}.
+
+ For even greater flexibility, you can specify a regular expression
+(@pxref{Regexps}). An apropos pattern is interpreted as a regular
+expression if it contains any of the regular expression special
+characters, @samp{^$*+?.\[}.
Here is a set of arguments to give to @kbd{C-h a} that covers many
-classes of Emacs commands, since there are strong conventions for naming
-the standard Emacs commands. By giving you a feel for the naming
-conventions, this set should also serve to aid you in developing a
-technique for picking @code{apropos} strings.
+classes of Emacs commands, since there are strong conventions for
+naming the standard Emacs commands. By giving you a feel for the
+naming conventions, this set should also serve to aid you in
+developing a technique for picking Apropos keywords.
@quotation
char, line, word, sentence, paragraph, region, page, sexp, list, defun,
view, describe, default.
@end quotation
+@findex apropos
+ To list all Lisp symbols that contain a match for an Apropos pattern,
+not just the ones that are defined as commands, use the command
+@kbd{M-x apropos} instead of @kbd{C-h a}. This command does not check
+key bindings by default; specify a numeric argument if you want it to
+check them.
+
@findex apropos-variable
- To list all user variables that match a regexp, use the command
-@kbd{M-x apropos-variable}. By default, this command shows only
-variables meant for user customization; if you specify a prefix
+ To list user-customizable variables that match an apropos pattern,
+use the command @kbd{M-x apropos-variable}. If you specify a prefix
argument, it checks all variables.
-@findex apropos
- To list all Lisp symbols that contain a match for a regexp, not just
-the ones that are defined as commands, use the command @kbd{M-x apropos}
-instead of @kbd{C-h a}. This command does not check key bindings by
-default; specify a numeric argument if you want it to check them.
-
+@kindex C-h d
@findex apropos-documentation
- The @code{apropos-documentation} command is like @code{apropos} except
-that it searches documentation strings as well as symbol names for
-matches for the specified regular expression.
+ The @code{apropos-documentation} command is like @code{apropos}
+except that it searches documentation strings instead of symbol names
+for matches for the specified Apropos pattern.
@findex apropos-value
- The @code{apropos-value} command is like @code{apropos} except that it
-searches symbols' values for matches for the specified regular
-expression. This command does not check function definitions or
-property lists by default; specify a numeric argument if you want it to
-check them.
+ The @code{apropos-value} command is like @code{apropos} except that
+it searches variables' values for matches for the pattern. With a
+prefix argument, it also checks symbols' function definitions and
+property lists.
@vindex apropos-do-all
If the variable @code{apropos-do-all} is non-@code{nil}, the commands
above all behave as if they had been given a prefix argument.
@vindex apropos-sort-by-scores
+@cindex apropos search results, order by score
By default, Apropos lists the search results in alphabetical order.
If the variable @code{apropos-sort-by-scores} is non-@code{nil},
Apropos tries to guess the relevance of each result, and displays the
most relevant ones first.
- If you want more information about a function definition, variable or
-symbol property listed in the Apropos buffer, you can click on it with
-@kbd{Mouse-1} or @kbd{Mouse-2}, or move there and type @key{RET}.
+@vindex apropos-documentation-sort-by-scores
+ By default, Apropos lists the search results for
+@code{apropos-documentation} in order of relevance of the match. If
+the variable @code{apropos-documentation-sort-by-scores} is
+@code{nil}, Apropos lists the symbols found in alphabetical order.
@node Library Keywords
@section Keyword Search for Lisp Libraries
libraries by topic keywords. Here is a partial list of keywords you can
use:
-@multitable {emulations} {aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa}
+@multitable {convenience} {aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa}
@item abbrev@tab abbreviation handling, typing shortcuts, macros.
@item bib@tab code related to the @code{bib} bibliography processor.
@item c@tab support for the C language and related languages.
the support for a specific language environment. @xref{Language
Environments}. This tells you which languages this language
environment is useful for, and lists the character sets, coding
-systems, and input methods that go with it. It also shows some sample
-text to illustrate scripts.
+systems, and input methods that it operates on. It also shows some
+sample text to illustrate scripts.
The command @kbd{C-h h} (@code{view-hello-file}) displays the file
@file{etc/HELLO}, which shows how to say ``hello'' in many languages.
@item @key{SPC}
Scroll forward.
@item @key{DEL}
-@itemx @key{BS}
-Scroll backward. On some keyboards, this key is known as @key{BS} or
-@key{backspace}.
+Scroll backward.
@item @key{RET}
Follow a cross reference at point.
@item @key{TAB}
@item Mouse-1
@itemx Mouse-2
Follow a cross reference that you click on.
+@item C-c C-c
+Show all documentation about the symbol at point.
@end table
- When a function name (@pxref{M-x,, Running Commands by Name}) or
-variable name (@pxref{Variables}) appears in the documentation, it
-normally appears inside paired single-quotes. You can click on the
-name with @kbd{Mouse-1} or @kbd{Mouse-2}, or move point there and type
-@key{RET}, to view the documentation of that command or variable. Use
-@kbd{C-c C-b} to retrace your steps.
+ When a function name (@pxref{M-x,, Running Commands by Name}),
+variable name (@pxref{Variables}), or face name (@pxref{Faces}) appears
+in the documentation, it normally appears inside paired single-quotes.
+You can click on the name with @kbd{Mouse-1} or @kbd{Mouse-2}, or move
+point there and type @key{RET}, to view the documentation of that
+command, variable or face. Use @kbd{C-c C-b} to retrace your steps.
+
+@cindex URL, viewing in help
+@cindex help, viewing web pages
+@cindex viewing web pages in help
+@cindex web pages, viewing in help
+@findex browse-url
+ You can follow cross references to URLs (web pages) as well. When
+you follow a cross reference that is a URL, the @code{browse-url}
+command is used to view the web page in a browser of your choosing.
+@xref{Browse-URL}.
@kindex @key{TAB} @r{(Help mode)}
@findex help-next-ref
next cross reference. Use @kbd{S-@key{TAB}} to move point up to the
previous cross reference (@code{help-previous-ref}).
+ You can view all documentation about any symbol name that appears in
+the text, by moving point to the symbol name and typing @kbd{C-c C-c}
+(@code{help-follow-symbol}). This shows all available documentation
+about the symbol as a variable, function and/or face. @kbd{C-c C-b}
+works in this case also, to retrace your steps.
+
@node Misc Help
@section Other Help Commands
need to get to the documentation quickly, and you know the exact name
of the file.
-@kindex C-h F
-@kindex C-h K
-@findex Info-goto-emacs-key-command-node
-@findex Info-goto-emacs-command-node
- There are two special help commands for accessing Emacs
-documentation through Info. @kbd{C-h F @var{function} @key{RET}}
-enters Info and goes straight to the documentation of the Emacs
-function @var{function}. @kbd{C-h K @var{key}} enters Info and goes
-straight to the documentation of the key @var{key}. These two keys
-run the commands @code{Info-goto-emacs-command-node} and
-@code{Info-goto-emacs-key-command-node}. You can use @kbd{C-h K} to
-find the documentation of a menu item: just select that menu item when
-@kbd{C-h K} prompts for a key.
-
- @kbd{C-h F} and @kbd{C-h K} know about commands and keys described
-in manuals other than the Emacs manual. Thus, they make it easier to
-find the documentation of commands and keys when you are not sure
-which manual describes them, like when using some specialized mode.
+ The help commands @kbd{C-h F @var{function} @key{RET}} and @kbd{C-h
+K @var{key}}, described above, enter Info and go straight to the
+documentation of @var{function} or @var{key}.
@kindex C-h S
@findex info-lookup-symbol
@cindex balloon help
When a region of text is ``active,'' so that you can select it with
the mouse or a key like @kbd{RET}, it often has associated help text.
-Areas of the mode line are examples. On most window systems, the help
+Areas of the mode line are examples. On graphical displays, the help
text is displayed as a ``tooltip'' (sometimes known as ``balloon
-help''). @xref{Tooltips}. Otherwise, it is shown in the echo area
-when you move point into the active text.
+help''), when you move the mouse over the active text. @xref{Tooltips}.
+On some systems, it is shown in the echo area. On text-only
+terminals, Emacs may not be able to follow the mouse and hence will
+not show the help text on mouse-over.
@kindex C-h .
@findex display-local-help