Gnome Alt + F2 clear command history

In a terminal run:

dconf-editor

In the program that pops up, navigate to:

org > gnome > shell

In there, find a key called

command-history

click on it and click the

"Set to Default"

button.

You need to restart the Gnome 3 desktop by log out / log in, or by pressing

<Alt>+<F2>

and then type in the text field

r

and press

<Enter>