From: Joel VanderWerf <vjoel@...>
Date: 2006-11-20T12:38:48+09:00
Subject: Re: backticks asynchronous?

Jason Mayer wrote:
> Sorry, reading this email reminded me of my project.  Say I wanted to do a
> bunch of pings using backticks (you may have asked my stupid n00b questin
> about ``).  If I wanted to do a bunch of pings, which would take some small
> amount of time, would it be better(faster) to start new threads before 
> doing
> the `ping whatever`, or is there a better/different way?

Sure, why not use threads:

t0 = Time.now

threads = (1..10).map do |i|
   Thread.new do
     addr = "192.168.0.#{i}"
     [addr, `ping -w3 -nq #{addr}`]
   end
end

values = threads.map {|thread| thread.value}
t1 = Time.now
puts "Finished in #{t1 - t0} seconds"

require 'yaml'
y values.select {|addr, out| out !~ / 0 received/}

__END__

Output:

Finished in 3.011614 seconds
---
- - 192.168.0.1
   - |
     PING 192.168.0.1 (192.168.0.1) 56(84) bytes of data.

     --- 192.168.0.1 ping statistics ---
     3 packets transmitted, 3 received, 0% packet loss, time 2001ms
     rtt min/avg/max/mdev = 2.032/3.052/4.750/1.210 ms

...

-- 
       vjoel : Joel VanderWerf : path berkeley edu : 510 665 3407