$ sudo apt-get remove knot-host 

Uninstall knot-host including dependent package

If you would like to remove knot-host and it's dependent packages which are no longer needed from Ubuntu,

$ sudo apt-get remove --auto-remove knot-host 

Use Purging knot-host

If you use with purge options to knot-host package all the configuration and dependent packages will be removed.

$ sudo apt-get purge knot-host 

If you use purge options along with auto remove, will be removed everything regarding the package, It's really useful when you want to reinstall again.

$ sudo apt-get purge --auto-remove knot-host 

See Also,