$ sudo apt-get update
$ sudo apt-get install elpa-aggressive-indent 

elpa-aggressive-indent is installed in your system.

Make ensure the elpa-aggressive-indent package were installed using the commands given below,

$ sudo dpkg-query -l | grep elpa-aggressive-indent *

You will get with elpa-aggressive-indent package name, version, architecture and description in a table

elpa-aggressive-indent package basic information: