bell - Ring a display's bell
bell ?-displayof window? ?-nice?
This command rings the bell on the display for window and returns an
empty string. If the -displayof option is omitted, the display of the
application's main window is used by default. The command uses the current
bell-related settings for the display, which may be modified with programs
such as xset.
If -nice is not specified, this command also resets the
screen saver for the screen. Some screen savers will ignore this, but others
will reset so that the screen becomes visible again.