+ |----------[#####|##########]--------------------------------------------|
+ ^ ^ ^ ^ ^
+ 2.5% 25% 50% 75% 97.5%
+
+=item B<histogram>
+
+Show a I<histrogram> of the round-trip times. The width of the window is taken
+as round-trip time from 0ms on the left to the I<interval> (the B<-i> option,
+default 1000ms) on the right.
+
+The height of the graph is scaled so that the most-used buckets vertically fills
+the line. The buckets are colored green up to and including the 80th
+percentile, yellow up to and including the 95th percentile and red for the
+remainder.
+
+=back
+
+=item B<-b>
+
+Audible bell. Print a ASCII BEL character (\a or 0x07) when a packet
+is received before the timeout occurs. This can be useful in order to
+monitory hosts' connectivity without looking physically at the
+console, for example to trace network cables (start audible beep,
+disconnect cable N: if beep stops, the cable was in use) or to tell
+when a host returns from a reboot.
+
+This relies on the terminal bell to be functional. To enable the
+terminal bell, use the following instructions.
+
+=over 4
+
+=item
+
+the visual bell is disabled in your terminal emulator, with the +vb
+commandline flag or the following in your .Xresources:
+
+ XTerm*visualBell: false
+
+=item
+
+the PC speaker module is loaded in your kernel:
+
+ modprobe pcspkr
+
+=item
+
+X11 has the terminal bell enabled:
+
+ xset b on; xset b 100
+
+=item
+
+and finally, if you are using PulseAudio, that the module-x11-bell
+module is loaded with a pre-loaded sample defined in your pulseaudio
+configuration:
+
+ load-sample-lazy x11-bell /usr/share/sounds/freedesktop/stereo/complete.oga
+ load-module module-x11-bell sample=x11-bell
+