Help
Emacs provides extensive help features accessible through a single
character, C-h. C-h is a prefix key that is used for
commands that display documentation. The characters that you can type after
C-h are called help options. One help option is C-h;
that is how you ask for help about using C-h. To cancel, type
C-g. The function key <F1> is equivalent to C-h.
C-h C-h (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 <SPC> or <DEL> to scroll through the list.
C-h or <F1> means "help" in various other contexts as
well. For example, in the middle of query-replace, it describes
the options available for how to operate on the current match. After a
prefix key, it displays a list of the alternatives that can follow the
prefix key. (A few prefix keys don't support C-h, because they
define other meanings for it, but they all support <F1>.)
Most help buffers use a special major mode, Help mode, which lets you
scroll conveniently with <SPC> and <DEL>. It also offers
hyperlinks to further help regarding cross-referenced names, Info nodes,
customization buffers and the like. See Help Mode.
If you are looking for a certain feature, but don't know where
exactly it is documented, and aren't sure of the name of a
related command or option, we recommend trying these methods. Usually
it is best to start with an apropos command, then try searching the
manual index, then finally look in the FAQ and the package keywords.
- C-h a topic <RET>
- This searches for commands whose names match topic, which should
be a regular expression (see Regexps). Browse the buffer that this
command displays to find what you are looking for. See Apropos.
- M-x apropos <RET> topic <RET>
- This works like C-h a, but it also searches for user options and
other variables, in case the feature you are looking for is controlled
by an option, not a command. See Apropos.
- M-x apropos-documentation <RET> topic <RET>
- This searches the documentation strings (the built-in short
descriptions) of all variables and functions (not their names) for a
match for topic, a regular expression. See Apropos.
- C-h i d m emacs <RET> i topic <RET>
- This looks up topic in the indices of the Emacs on-line manual.
If there are several matches, Emacs displays the first one. You can then
press <,> to move to other matches, until you find what you are
looking for.
- C-h i d m emacs <RET> s topic <RET>
- Similar, but searches for topic (which can be a regular
expression) in the text of the manual rather than in its
indices.
- C-h F
- This brings up the Emacs FAQ, where you can use the usual search
commands (see Search) to find the information.
- C-h p
- Finally, you can try looking up a suitable package using keywords
pertinent to the feature you need. See Library Keywords.
To find the documentation of a key sequence or a menu item, type
C-h C-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 C-h C-f for reading documentation of a
command.
- Help Summary: Brief list of all Help commands.
- Key Help: Asking what a key does in Emacs.
- Name Help: Asking about a command, variable or function name.
- Apropos: Asking what pertains to a given topic.
- Library Keywords: Finding Lisp libraries by keywords (topics).
- Language Help: Help relating to international language support.
- Help Mode: Special features of Help mode and Help buffers.
- Misc Help: Other help commands.
- Help Echo: Help on active text and tooltips (`balloon help')
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