$ sudo apt-get remove ircd-ircu 

Uninstall ircd-ircu including dependent package

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

$ sudo apt-get remove --auto-remove ircd-ircu 

Use Purging ircd-ircu

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

$ sudo apt-get purge ircd-ircu 

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 ircd-ircu 

See Also,