$ sudo apt-get remove i3blocks 

Uninstall i3blocks including dependent package

If you would like to remove i3blocks and it's dependent packages which are no longer needed from Ubuntu,

$ sudo apt-get remove --auto-remove i3blocks 

Use Purging i3blocks

If you use with purge options to i3blocks package all the configuration and dependent packages will be removed.

$ sudo apt-get purge i3blocks 

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 i3blocks 

See Also,