What is the -w (deadline) flag in ping for? I cannot find a description of it in the ping man page; only for -W, which takes seconds as a parameter. What is the difference between them, and how can I set a ping timeout (if host is not responding) to 200ms?
What is the difference between ping -w and ping -W?
shell;ping;timeout
From man ping:   -w deadline          Specify a timeout, in seconds, before ping exits regardless of how many packets have been sent or received. In this case ping does not stop after count packet are sent, it waits either for deadline expire or until count probes are answered or for some error          notification from network.   -W timeout          Time to wait for a response, in seconds. The option affects only timeout in absense of any responses, otherwise ping waits for two RTTs.That is, -w sets the timeout for the entire program session. If you set -w 30, ping (the program) will exit after 30 seconds.-W on the other hand sets the timeout for a single ping. If you set -W 1, that particular ping attempt will time out.As for how to set an individual ping timeout of 200ms, I don't believe this can be done with iputils' version of ping. You might want to try directly programming with an ICMP library.