def update(*filenames)
    puts send_cmd("update "+filenames.map{|f| OptArg.quote(f)}.join(" "))
  end
def update(*filenames)
    puts send_cmd("update "+filenames.map{|f| OptArg.quote(f)}.join(" "))
  end
This command writes the current values of the fit parameters into
 the given file, formatted as an initial-value file (as described
 in the `fit`section).  This is useful for saving the current
 values for later use or for restarting a converged or stopped fit.