[ltp] OT: how to time a ping command?

[Eben King]

On Mon, 20 Sep 2004, André Wyrwa wrote:

> can anyone tell me how i can time a ping command? I can do a -c 1 -i 0
> to time one resulting positive, but if the server is not found the
> command never returns, so it seems i need to find a way to terminate it
> from outside after some time. But how (killall is to be avoided)?

from ping.1:

   -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.

I think that'll do what you want.

I implemented such a test once.  As either I did not know about that or it 
didn't exist at the time, what I did was something like

ping -c 1 somehost > ping_output &
sleep 1
kill %1
grep -q 'some_expr' ping_output && ip_up

although I'm sure there were some loops and a wait in there.

-- 
-eben    ebQenW1@EtaRmpTabYayU.rIr.OcoPm    home.tampabay.rr.com/hactar

      Hanlon's Razor: "Never attribute to malice that which can be 
    adequately explained by stupidity."  Derived from Robert Heinlein