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 this:

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.
-no-wobble Keep the display stationary instead of very slowly wobbling back and forth.
-no-dns Do not attempt to resolve IP addresses to hostnames.
-no-times 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.

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