53
votes
Accepted
What is the difference between a function and a command?
Every command is a function, but not every function is also a command.1
A command includes a call to interactive; this is why commands are commonly referred to as "interactive functions". Commands ...
- 14.2k
47
votes
How can I start learning Emacs Lisp?
What a great question! Here is the path I've taken:
Step 0: Read the Emacs Tutorial
Read the Emacs Tutorial before anything else. It sounds like you've done this. Good on ya! However, for anyone ...
- 3,835
29
votes
Accepted
How can I start learning Emacs Lisp?
In my experience, the included tutorial on Emacs Lisp was not too helpful (I tried twice over the years and failed). Instead, I finally used the included Emacs Lisp Reference.
What finally did work:
...
- 560
18
votes
If I know a keybinding/shortcut, how to get the corresponding function?
The describe-key command (C-h k) will tell you what command is bound to a given key sequence. To go the other way and find out what keys (if any) are bound to a command, use where-is (C-h w).
You can ...
- 19.1k
15
votes
Accepted
How can I look up help for a key sequence that I can't type
Evaluate the following using eval-expression (M-:) or in a scratch buffer:
(describe-key (kbd "C-<whatever>"))
- 4,950
13
votes
Info file emacs does not exist
That error is because the full documentation is not installed by default.
Solve it by installing emacs25-common-non-dfsg
# aptitude install emacs25-common-non-dfsg
Test it by trying,
C-h i h
It ...
- 306
13
votes
Change focus to *Help* buffer after running describe-mode
Customize the variable help-window-select:
"Non-nil means select help window for viewing.
Choices are:
never (nil) Select help window only if there is no other window
on its frame.
...
- 17.6k
13
votes
Emacs manuals are missing on Debian/Ubuntu
This is a great question!
I've found the directions online to install it by hand unclear and, frankly, a bit of a pain (at least on Debian).
On Debian...
Emacs on Debian doesn't come with the Emacs ...
- 3,835
12
votes
Accepted
Is there a command `describe-command', similar to command `describe-function'?
Yes. Library help-fns+.el defines command describe-command.
And it redefines describe-function so that it does describe-command if you give it a prefix arg.
The library binds describe-command to C-h ...
- 69.2k
11
votes
Accepted
Why does GNU Emacs use ksi(ξ) as its logo?
It doesn't. It uses just an E that is suggestive of a gnu's horns.
- 69.2k
11
votes
How can I start learning Emacs Lisp?
I recommend the "Emacs Lisp Intro".
The "Emacs Lisp Intro" might be already available in info format within your Emacs. Try C-h i m Emacs Lisp Intro RET or evaluate (info "(eintr) Top") in Emacs.
...
- 2,646
10
votes
How to get the function help without typing?
From gnu.org:
If you type C-h f <RET>, it describes the function called by the
innermost Lisp expression in the buffer around point, provided that
function name is a valid, defined Lisp ...
- 1,538
10
votes
Accepted
How to describe a key sequence that starts with `C-u`?
Prefix keys like C-u may be described in the function body. You should therefore ignore such prefix keys when using C-h k to describe a function.
- 5,325
10
votes
Accepted
How to discover (standard) function names?
Apropos help in Emacs is by no means limited to function apropos.
M-x apropos documentation. It lets you match keywords or a regexp against doc strings. Very helpful when you don't know how the ...
- 69.2k
9
votes
Accepted
How to look up documentation for a minor mode?
You've seen the basics, really. Your main problem was that this documentation was wrong, not that you weren't looking in the right place.
The slightly more direct way to read that documentation for a ...
- 43.1k
9
votes
How can I look up help for a key sequence that I can't type
If you can't use a particular key combination because of your terminal, you can often fake it by manually simulating the key modifier. The following combinations work exactly as though you had used ...
- 1,316
9
votes
Is there a command `describe-command', similar to command `describe-function'?
apropos-command might be sufficiently close.
It doesn’t offer describe-function’s tab completion, but it lets you
search only through commands, and it takes you
to their doc page.
- 22.3k
9
votes
Accepted
How do I create a button in Emacs?
You can use both make-button or make-text-button. For example
(defun button-pressed (button)
(message (format "Button pressed!")))
(define-button-type 'custom-button
'action 'button-pressed
'...
- 801
9
votes
Accepted
How to view package Full Description (commentary section) inside Emacs
M-x finder-commentary RET <library-name> RET extracts that section and presents it in a separate buffer for reading. There is also M-x finder-by-keyword for discovering libraries this way.
- 21k
9
votes
Accepted
Are the graphical depictions in docs drawed in manual labour?
Included with emacs is a basic tool called picture-mode:
To edit a picture made out of text characters (for example, a picture of
the division of a register into fields, as a comment in a program)...
- 6,943
8
votes
Is there a command `describe-command', similar to command `describe-function'?
if you have smex installed, just call smex. Start to type, when the right one comes up, press C-h f.
- 1,706
8
votes
What's :eval (colon eval) in defcustom?
The doc string tells you this:
"Mode line lighter for Github Notifier."
You couldn't otherwise know for sure what the code is about, or what :eval means in that context. That is, you ...
- 69.2k
7
votes
Is there a command `describe-command', similar to command `describe-function'?
I can't find this built-in. It is fairly easy to make a wrapper around describe-function that only completes command names when called interactively. In the implementation below, I duplicated the ...
7
votes
Accepted
What are possible real use cases of the Emacs "psychotherapist" mode?
Eliza stems from 1960s research in AI. It goes beyond the fun as far as AI research is concerned; it's wildly out of date, but still a common, reasonably fun programming exercise. As far as ...
7
votes
Accepted
How do I customize the way Emacs prints out certain keys and key sequences?
Yes. There is a function key-description that takes a list or vector of keys and returns a string that describes them. This is used by the built-in help facilities such as describe-key and describe-...
- 11.4k
7
votes
Accepted
How can I have multiple *Help* buffers with different content?
You can use rename-uniquely. Go to the help buffer, call rename-uniquely. It renames the buffer to something like *Help*<2>. Now If you open another help buffer, it doesn't affect *Help*<2>...
- 693
7
votes
How can I start learning Emacs Lisp?
Start with the Emacs Wiki page Learn Emacs Lisp.
Not that that page itself will teach you Emacs Lisp. It will instead point to learning resources -- exactly what you're looking for here, with your ...
- 69.2k
7
votes
Accepted
Meaning of "value is t"
To quote the Emacs Lisp Manual,
t is the preferred way to represent the truth value true. When you
need to choose a value that represents true, and there is no other
basis for choosing, use t. ...
- 3,835
6
votes
Accepted
How to see the name of the command every time I run it by a shortcut?
You can use post-command-hook.
(defun my-echo-command-name-hook ()
(unless (or (eq this-command 'self-insert-command)
(eq this-command 'next-line))
(message "%s" this-command)))
(...
- 1,639
6
votes
How can I have multiple *Help* buffers with different content?
You can also use command/function clone-buffer.
M-x clone-buffer in buffer *Help* opens a new buffer *Help*<2> (or *Help*<3> if there is already a buffer *Help*<2>, etc.).
Same ...
- 69.2k
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