alert
and notify-send
seem to be the same thing. I use notify-send
for non-input messages as it doesn't steal focus and I cannot find a way to stop zenity etc. from doing this.
e.g.
# This will display message and then disappear after a delay:
notify-send "job complete"
# This will display message and stay on-screen until clicked:
notify-send -u critical "job complete"