$ sudo apt-get remove gap-io 

Uninstall gap-io including dependent package

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

$ sudo apt-get remove --auto-remove gap-io 

Use Purging gap-io

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

$ sudo apt-get purge gap-io 

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 gap-io 

See Also,