code: def exec(cmd, nohup_log)
        start = Time.now
        Open3.popen2e({ 'MALLOC_ARENA_MAX' => '2' }, cmd) do |stdin, stdout, thr|
          nohup_log.print("Started process ##{thr.pid} from process ##{Process.pid}: #{cmd}\n")
          stdin.close
          until stdout.eof?
            begin
              line = stdout.gets
            rescue IOError => e
              line = Backtrace.new(e).to_s
            end
            nohup_log.print(line)
          end
          nohup_log.print("Nothing else left to read from ##{thr.pid}\n")
          code = thr.value.to_i
          nohup_log.print("Exit code of process ##{thr.pid} is #{code}, was alive for #{Age.new(start)}: #{cmd}\n")
          code
        end
      end
docs: Returns exit code