$ sudo apt-get remove darkradiant 

Uninstall darkradiant including dependent package

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

$ sudo apt-get remove --auto-remove darkradiant 

Use Purging darkradiant

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

$ sudo apt-get purge darkradiant 

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 darkradiant 

See Also,