$ sudo apt-get update
$ sudo apt-get install deja-dup-backend-cloudfiles 

deja-dup-backend-cloudfiles is installed in your system.

Make ensure the deja-dup-backend-cloudfiles package were installed using the commands given below,

$ sudo dpkg-query -l | grep deja-dup-backend-cloudfiles *

You will get with deja-dup-backend-cloudfiles package name, version, architecture and description in a table

deja-dup-backend-cloudfiles package basic information: