$ nvidia-settings -q RefreshRate

  Attribute 'RefreshRate' (stimpy:0.0; display device: TV-0): 60.32 Hz.
    'RefreshRate' is an integer attribute.
    'RefreshRate' is a read-only attribute.
    'RefreshRate' is display device specific.
    'RefreshRate' can use the following target types: X Screen, GPU.
  Attribute 'RefreshRate' (stimpy:0.0; display device: DFP-0): 59.97 Hz.
    'RefreshRate' is an integer attribute.
    'RefreshRate' is a read-only attribute.
    'RefreshRate' is display device specific.
    'RefreshRate' can use the following target types: X Screen, GPU.