Dismiss all notifications

dismiss_notifications.sh

osascript -e '
tell application "System Events"
  tell process "NotificationCenter"
    if not (window "Notification Center" exists) then return
    set alertGroups to groups of first UI element of first scroll area of first group of window "Notification Center"
    repeat with aGroup in alertGroups
      try
        perform (first action of aGroup whose name contains "Close" or name contains "Clear")
      on error errMsg
        log errMsg
      end try
    end repeat
    -- Show no message on success
    return ""
  end tell
end tell'

cf: https://www.reddit.com/r/MacOS/comments/1f92zj7/comment/lljccxb/