Define Key Shortcuts in Emacs

Set a keybind: (global-set-key <key> <command>) (global-set-key <key> <command>) and (define-key global-map <key> <command>) are basically the same thing in most cases;
Switch to another buffer: C-x b
Open file: C-x C-f
Cancel a command: C-g
Quit Emacs: C-x C-c
Find out the current keybinding of a key, for example, C-x C-e: press C-h k, then press C-x C-e;
List all current key bindings:
Get last executed command, for example: use "C-x b" to switch to another window: Press C-x b, select "Messages", Press C-x , then you can see the last executed command "(switch-to-buffer "Message")";

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