#! /bin/bash
selection=$(zenity --list "Option 1" "Option 2" "Option 3" --column="" --text="Text above column(s)" --title="My menu")
case "$selection" in
"Option 1")zenity --info --text="Do something here for No1";;
"Option 2")zenity --info --text="Do something here for No2";;
"Option 3")zenity --info --text="Do something here for No3";;
esac