gistfile1.rb

    def YWSystemTools.runMultithreaded(commandArray)
        # runs commands on N processors at a time - can take more jobs & launches them sequentially.

        if commandArray.length > 1
            $log.info("#{commandArray.length} commands to run")
        elsif commandArray.length == 1
            $log.warn("only one command!")
        else
            raise ArgumentError, 'No commands to run!'
        end

        #determining how many procs to use
        threads = []                                                                                               
        numberOfProcessorsToUse = YWSystemTools.numberOfAvailableProcessors
        $log.info("Will use #{numberOfProcessorsToUse} processors")

        if numberOfProcessorsToUse == 1
            $log.warn("Not running multithreaded because there is only one processor")
        elsif numberOfProcessorsToUse == 0
            $log.warn("No processors available - will nevertheless use one")
            numberOfProcessorsToUse == 1
        end
        if (commandArray.length < numberOfProcessorsToUse) # we need less
            numberOfProcessorsToUse = commandArray.length
        end
        


        # we need one name per processor & have some margin
        ('proc00001'..'proc10000').entries[1..numberOfProcessorsToUse].each do |processor|
            threads << Thread.new(processor) do |threadid|                                                          
                until commandArray.empty?
                    commandToRun = commandArray.pop
                    $log.info('running:' + commandToRun)
##                    %x[#{commandToRun}] 
                    stdout = %x[#{commandToRun}]
                    print(stdout)
                end
            end
        end    

        # wait until all are done.
        threads.each { |aThread|  aThread.join }
    end