Raspistill command not found on RPi 3B Ubuntu mate v18

Hi, I have encountered an issue regarding the raspistill command.

I have done sudo apt-get update and sudo apt-get upgrade respectively and also enabled the camera interface with sudo raspi-config.

When I wanted to test the camera with raspistill -v -o test.jpg it says command not found.

Any ideas how can I fix this problem? I had connected the camera to the Raspberry pi as well.