#!/usr/bin/octave-cli --persist
  
  filename = argv(){1};
  col = eval(argv(){2});
  mult = eval(argv(){3});
  
  if length(col) == length(mult)
      figure
      hold all
      grid on
      cc = 'bkcgmry';
      for i = [1:length(col)]
          data.freq = load(filename)(:,col(i)).*mult(i);
          data.rate = 1;
          [p, f] = pwelch(data.freq, [], 0.95, [], data.rate.*mult(i), 'onesided');
          semilogx(f, 10*log10(p), cc(mod(i, length(cc))))
          leg{i} = strcat(filename, ' col', num2str(col(i)));
          hold on
      end
      legend(leg)
      input("Press to continue...");
  end
  exit