If you need to convert files from one markup format into another, Pandoc is your swiss-army knife.
The following code will upgrade Pandoc on Ubunutu to version 1.19.2.1.
Run pandoc -v to see which version you're currently using.
sudo wget https://github.com/jgm/pandoc/releases/download/1.19.2.1/pandoc-1.19.2.1-1-amd64.deb sudo dpkg -i pandoc-1.19.2.1-1-amd64.deb
Run pandoc -v to see the new version.
You should now see "pandoc 1.19.2.1".