$ sudo apt-get remove aria2 

Uninstall aria2 including dependent package

If you would like to remove aria2 and it's dependent packages which are no longer needed from Ubuntu,

$ sudo apt-get remove --auto-remove aria2 

Use Purging aria2

If you use with purge options to aria2 package all the configuration and dependent packages will be removed.

$ sudo apt-get purge aria2 

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 aria2 

See Also,