Provided by: xscreensaver-gl_6.02+dfsg1-2ubuntu2_amd64 
NAME
sonar - display a sonar scope
SYNOPSIS
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]
DESCRIPTION
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.
OPTIONS
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 IPv4 address.
subnet Ping the local subnet. On systems where we can determine the local
network mask, we use that; otherwise, we assume Class C (254 hosts).
subnet/NN Ping a different-sized local subnet: e.g., subnet/28 would ping a
4-bit subnet (the nearest 14 addresses). On systems where we can
determine the local network mask, we always use that.
A.B.C.D/NN Ping an arbitrary other IPv4 subnet. The address specifies the base
address, and the part after the slash is how wide the subnet is.
Typical values are /24 (for 254 addresses) and /28 (for 14 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.
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.)
INSTALLATION
For this program to be able to ping other hosts, it must have the ability to open ICMP
sockets, which is usually an action that requires additional privileges.
If your system has setcap(8) then this permission can be added with
setcap cap_net_raw=p sonar
Otherwise, the program must be setuid root in order to ping hosts. 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 use setcap or setuid on macOS systems, as unprivileged programs can
ping by using ICMP DGRAM sockets instead of ICMP RAW.
BUGS
Does not support IPv6.
SEE ALSO
X(1), xscreensaver(1), ping(8), ping6(8)
COPYRIGHT
Copyright © 2000-2021 by Jamie Zawinski <jwz@jwz.org>
Copyright © 1998 by Stephen Martin. <smartin@canada.com>
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.
AUTHORS
Stephen Martin <smartin@canada.com>, 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.