$ sudo apt-get update
$ sudo apt-get install libclhep2.1v5 

libclhep2.1v5 is installed in your system.

Make ensure the libclhep2.1v5 package were installed using the commands given below,

$ sudo dpkg-query -l | grep libclhep2.1v5 *

You will get with libclhep2.1v5 package name, version, architecture and description in a table

libclhep2.1v5 package basic information: