Binary package “dunst” in ubuntu bionic

dmenu-ish notification-daemon

 Dunst is a highly configurable and lightweight notification-daemon: The
 only thing it displays is a colored box with unformatted text. The whole
 notification specification (non-optional parts and the "body" capability) is
 supported as long as it fits into this look & feel.
 .
 Dunst is designed to fit nicely into minimalistic windowmanagers like dwm, but
 it should work on any Linux desktop.