Useful Describe Keys in Emacs

What captures the beauty of Emac’s self-documenting nature is the describe system of commands. If you know what you’re looking for, then describe will explain what it is

– Mastering Emacs

Many a times in GNU Emacs you get stuck trying to figure out what some key strokes do. Sometimes, you get someone’s config(emacs.d/init.el) file and you wonder what those goddamn minor/ major modes do. Well, Emacs inbuilt describe system makes work easier as it helps you, the user, know what stuff does. Below, I list some of the most important key bindings in GNU Emacs which you’ll probably (maybe) use in your daily interaction with GNU Emacs:

1. C-h m/ M-x describe-mode: Running this command will display the major mode and any minor modes enabled in the current buffer along with any key-bindings introduced by said modes
2. C-h k/ M-x describe-key: Describe key-binding.
3. C-h v/ M-x describe-variable: Describes a variable.
4. C-h f/ M-x describe-function: Describes a function and any other relevant details pertaining that function. Here’s an example of what is displayed by running M-x describe-function followed by list-packages:

list-packages is an interactive autoloaded compiled Lisp function in
‘package.el’.

(list-packages &optional NO-FETCH)

:around advice: fullframe-command-on-advice

Display a list of packages.
This first fetches the updated list of packages before
displaying, unless a prefix argument NO-FETCH is specified.
The list is displayed in a buffer named ‘*Packages*’.

[back]

References:
1. Mastering Emacs by Mickey Petersen