/usr/bin/nvidia-modprobe: unrecognized option: "-s"

I also faced issue after updating my driver to 455.45.01, above instructions works, This would also solve the issue, without adding PPA.

wget http://developer.download.nvidia.com/compute/cuda/repos/ubuntu1804/x86_64/nvidia-modprobe_455.45.01-0ubuntu1_amd64.deb

and then install with

sudo dpkg -i nvidia-modprobe_455.45.01-0ubuntu1_amd64.deb

I had exactly the same problem after recent update to 450.80.2. In my case the following got the issue resolved:

1. Add / enable PPA http://developer.download.nvidia.com/compute/cuda/repos/ubuntu1804/x86_64
2. sudo apt-get update
3. Optionally verify candidates are available: sudo apt-cache policy nvidia-modprobe
4. sudo apt-get install nvidia-modprobe=450.80.02-0ubuntu1
5. Remove / disable PPA if you do not intend using it soon again.

Here is what worked for me (basically it is Keivan's comment on the accepted answer, but downloading using https instead of http).

# Change 'nvidia-modprobe_470.42.01-0ubuntu1_amd64.deb' below to the latest version at the time you execute (see the link to find it)    
wget https://developer.download.nvidia.com/compute/cuda/repos/ubuntu1804/x86_64/nvidia-modprobe_470.42.01-0ubuntu1_amd64.deb

sudo dpkg -i nvidia-modprobe_470.42.01-0ubuntu1_amd64.deb