If you want a really simple screen recorder in Ubuntu Linux or from any derivative of Ubuntu, such as Mint for example, you can install it by adding this PPA repository to your sources, by running the following Terminal commands:
Install Green Recorder on Ubuntu
$ sudo add-apt-repository ppa:mhsabbagh/greenproject $ sudo apt update $ sudo apt install green-recorder
It contains a really simple interface. It will ask you what format, the name of the recorded file, where to place the recording, the number of frames per second, and the quality of the video from a range starting with 1 being the best to 10 being the worst.
Visit the Green Recorder website.