CODE EXAMPLE FOR SHELL

ubuntu 18.04 create folders in dock

For files : 
https://askubuntu.com/questions/966740/how-do-i-pin-my-favorite-folders-in-ubuntu-dock-like-in-windows

For apps : 
https://askubuntu.com/questions/1091972/how-do-i-create-app-folders-in-the-gnome-application-menu