class EventMachine::DeferrableChildProcess

from the child process.
#open calls its callbacks, passing the data returned
When the forked child terminates, the Deferrable that

command in a forked child process.
It also invokes EventMachine#popen to run the passed-in

returns an EventMachine::Deferrable object, without blocking.
string (including arguments if desired). #open immediately
#open takes a String argument containing an shell command
Sugars a common use-case involving forked child processes.

def self.open cmd
  EventMachine.popen( cmd, DeferrableChildProcess )
end