$ sudo apt-get remove cmdtest 

Uninstall cmdtest including dependent package

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

$ sudo apt-get remove --auto-remove cmdtest 

Use Purging cmdtest

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

$ sudo apt-get purge cmdtest 

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 cmdtest 

See Also,