Emacs has no limits. It has endless modules and even more functions. Logically you end up with numerous key-combinations. Even if you figure to remember a lot of them by using them, you might happen to forget key combinations you use less. Well, that is my case :)

The one nice thing in Emacs is that a lot of key-combinations are grouped by prefix. i.e. C-c p for projectile, C-h for help, etc. Personally I use f5 as a prefix for custom functions I wrote.

Enters which-key mode. Install it from Melpa and add following line to your Emacs configuration.

(which-key-mode)

Which-key will pop-up a list of key-completions starting with the prefix you enter, adding the name of the function called.

There are some customizations available which you’ll find in the README.org file of the project. Most concern the location of the list (to the right, left, bottom of the screen or in the mini-buffer or also to the right for short lists but moving to the bottom when the list becomes bigger). I choose to keep the default but modified the time lapse before it appears (default 1 second) to 1/2 second. This is the configuration line to add for this:

(setq which-key-idle-delay 0.5)

Check it out if you can’t remember all keystrokes as I do!