Provided by: xscreensaver-data-extra_5.15-2ubuntu1_amd64 bug


       sonar - display a sonar scope


       sonar  [-ping hosts-or-subnets] [-ping-timeout int] [-delay usecs] [-speed ratio] [-sweep-
       size ratio] [-font-size points] [-team-a-name string] [-team-b-name string] [-team-a-count
       int] [-team-b-count int] [-no-dns] [-no-times] [-no-wobble] [-debug] [-fps]


       This  draws a sonar screen that pings (get it?) the hosts on your local network, and plots
       their distance (response time)  from  you.   The  three  rings  represent  ping  times  of
       approximately 2.5, 70 and 2,000 milliseconds respectively.

       Alternately, it can run a simulation that doesn't involve hosts.


       sonar understands the following options:

       -ping hosts-or-subnets
               The  list of things to ping, separated by commas or spaces.  Elements of this list
               may be:

               simulation  Run in simulation mode instead of pinging real hosts.

               hostname    Ping the given host.

               A.B.C.D     Ping the given IP address.

               subnet      Ping the local class C subnet (the nearest 255 addresses).

               subnet/NN   Ping a different-sized local subnet:  e.g.,  subnet/28  would  ping  a
                           4-bit subnet (the nearest 15 addresses).

               A.B.C.D/NN  Ping  an  arbitrary  other  subnet.  The IP address specifies the base
                           address, and the part after the slash  is  how  wide  the  subnet  is.
                           Typical values are /24 (for 255 addresses) and /28 (for 15 addresses).

               filename    Ping  the  hosts  listed  in  the given file.  This file can be in the
                           format used by /etc/hosts, or it can be any file that has  host  names
                           as  the  first  or  second  element on each line.  If you use ssh, try

                             sonar -ping $HOME/.ssh/known_hosts

       -ping-timeout int
               The amount of time in milliseconds the program will wait for an answer to a ping.

       -delay int
               Delay between frames, in microseconds.  Default 20000.

       -speed ratio
               Less than 1 for slower, greater than 1 for faster.  Default 1.

       -sweep-size ratio
               How big the glowing sweep area should be. Default 0.3.

       -font-size points
               How large the text should be.  Default 10 points.

               Keep the display stationary instead of very slowly wobbling back and forth.

       -no-dns Do not attempt to resolve IP addresses to hostnames.

               Do not display ping times beneath the host names.

       -team-a-name string
               In simulation mode, the name of team A.

       -team-b-name string
               In simulation mode, the name of team B.

       -team-a-count int
               In simulation mode, the number of bogies on team A.

       -team-b-count int
               In simulation mode, the number of bogies on team B.

       -fps    Display the current frame rate, polygon count, and CPU load.


       On most Unix systems, this program must be installed as  setuid  root  in  order  to  ping
       hosts.   This  is  because  root  privileges  are  needed  to  create  an ICMP RAW socket.
       Privileges are disavowed shortly after startup (just after connecting to the X server)  so
       this is believed to be safe:
       chown root:root sonar
       chmod u+s sonar
       It  is  not  necessary  to make it setuid on MacOS systems, because on MacOS, unprivileged
       programs can ping by using ICMP DGRAM sockets instead of ICMP RAW.

       In ping-mode, the display is a logarithmic scale,  calibrated  so  that  the  three  rings
       represent ping times of approximately 2.5, 70 and 2,000 milliseconds respectively.

       This  means  that  if any the hosts you are pinging take longer than 2 seconds to respond,
       they won't show up; and if you are pinging several hosts with very  fast  response  times,
       they will all appear close to the center of the screen (making their names hard to read.)


       X(1), xscreensaver(1), ping(8)


       Copyright © 2000-2008 by Jamie Zawinski <>
       Copyright © 1998 by Stephen Martin. <>

       Permission  to use, copy, modify, distribute, and sell this software and its documentation
       for any purpose is hereby granted without fee, provided that the  above  copyright  notice
       appear in all copies and that both that copyright notice and this permission notice appear
       in supporting documentation.  No representations are made about the  suitability  of  this
       software for any purpose.  It is provided "as is" without express or implied warranty.


       Stephen Martin <>, 3-nov-1998.

       Subnet support, etc. added by Jamie Zawinski, 17-Jul-2000.

       Rewritten using OpenGL instead of X11 by Jamie Zawinski, 12-Aug-2008.